calcium carbonate (OTC)

Antacid

Take at onset of GI distress

Tums Regular, Tums Freshers (500 mg): Chew 2-4 tablets; not to exceed 15 tabs/24 hr

Tums Smoothies (750 mg): Chew 2-4 tablets; not to exceed 10 tabs/24 hr

Tums Extra (750 mg): Chew 2-4 tablets; not to exceed 9 tabs/24 hr

Tums Ultra (1000 mg): Chew 2-3 tablets; not to exceed 7 tabs/24 hr

Tums Chewy Delights (1177 mg): Chew and swallow 2-3 chews; not to exceed 10 chews/24 hr

Not to exceed 7 g/day

Calcium Supplementation

500 mg to 4 g PO qDay or divided q6-12hr with meals

Recommended Dietary Allowance

19-50 years: 1 g/day PO

Females

• >51 years: 1.2 g/day PO

Males

• 51-70 years: 1 g/day PO
• >71 years: 1.2 g/day PO

Dosing Considerations

Calcium carbonate (elemental calcium equivalent)

Approximately 40% of calcium carbonate is elemental calcium; 1000mg of calcium carbonate = 400 mg of elemental calcium

• 400 mg (161 mg)
• 500 mg (200 mg)
• 750 mg (300 mg)
• 1000 mg (400 mg)
• 1250 mg (500 mg)
• 1500 mg (600 mg)
• 1177 mg (470 mg)

Hyperphosphatemia (Orphan)

Treatment of hyperphosphatemia in patients with end-stage renal disease

Orphan indication sponsor

• R & D Laboratories, Inc; 4204 Glencoe Avenue; Marina Del Rey, CA 90292

Antacid

Children's Pepto

• <2 years (<11 kg): Safety and efficacy not established
• 2-5 years (12-21 kg): 400 mg (1 tablet) PO PRN; not to exceed 3 tablets/day
• 6-11 years (22-43 kg): 800 mg (2 tablets) PO PRN; not to exceed 6 tablets/day

Tums Kids

• <2 years (<11 kg): Safety and efficacy not established
• 2-4 years (11-21 kg): 375 mg (1/2 tablet) PO BID with meal
• >4 years (22-43 kg): 750 mg (1 tablet) PO TID with meal

Recommended Dietary Allowance

Dosage expressed as elemental calcium

0-6 months: 200 mg/day PO

7-12 months: 260 mg/day PO

1-3 years: 700 mg/day PO

4-8 years: 1000 mg/day PO

9-18 years: 1300 mg/day PO

Dosing Considerations

Calcium carbonate (elemental calcium equivalent)

• 400 mg (161 mg)
• 500 mg (200 mg)
• 750 mg (300 mg)
• 1000 mg (400 mg)
• 1250 mg (500 mg)
• 1500 mg (600 mg)
• 1177 mg (470 mg)

Contraindicated (1)

• ceftriaxone

  ceftriaxone, calcium carbonate. Other (see comment). Contraindicated. Comment: Do not use ANY calcium containing solutions (including Ringer or Harmann solutions) in combination with IV ceftriaxone; risk of potentially fatal particulate precipitation in lungs, kidneys. Separate by at least 48 hrs.

Serious - Use Alternative (21)

• atazanavir

  calcium carbonate will decrease the level or effect of atazanavir by increasing gastric pH. Applies only to oral form of both agents. Avoid or Use Alternate Drug. Atazanavir solubility decreases as pH increases. Reduced plasma concentrations of atazanavir are expected if antacids or buffered medications are coadministered. Administer atazanavir 2 hr before or 1 hr after these medications.

• baloxavir marboxil

  calcium carbonate will decrease the level or effect of baloxavir marboxil by cation binding in GI tract. Avoid or Use Alternate Drug. Baloxavir may bind to polyvalent cations resulting in decreased absorption. Studies in monkeys showed concurrent use with calcium, aluminum, or iron caused significantly decreased plasma levels. Human studies not conducted.

• dapsone

  calcium carbonate will decrease the level or effect of dapsone by increasing gastric pH. Applies only to oral form of both agents. Avoid or Use Alternate Drug.

• dasatinib

  calcium carbonate will decrease the level or effect of dasatinib by increasing gastric pH. Applies only to oral form of both agents. Avoid or Use Alternate Drug.

• demeclocycline

  calcium carbonate, demeclocycline. Either decreases levels of the other by inhibition of GI absorption. Applies only to oral form of both agents. Avoid or Use Alternate Drug. Separate by 2 hours.

• digoxin

  calcium carbonate will increase the level or effect of digoxin by increasing gastric pH. Applies only to oral form of both agents. Avoid or Use Alternate Drug.

• doxycycline

  calcium carbonate, doxycycline. Either decreases levels of the other by inhibition of GI absorption. Applies only to oral form of both agents. Avoid or Use Alternate Drug. Separate by 2 hours.

• eltrombopag

  calcium carbonate decreases levels of eltrombopag by inhibition of GI absorption. Applies only to oral form of both agents. Contraindicated. Separate by at least 4 hours.

• erdafitinib

  calcium carbonate, erdafitinib. Other (see comment). Avoid or Use Alternate Drug. Comment: Avoid coadministration during initial dosing adjustment period (ie, first 21 days). Increases in serum phosphate levels are a pharmacodynamic effect of FGFR inhibition. Serum phosphate binders may obscure decisions regarding initial dosage increase.

• indinavir

  calcium carbonate will decrease the level or effect of indinavir by increasing gastric pH. Applies only to oral form of both agents. Avoid or Use Alternate Drug.

• infigratinib

  calcium carbonate will decrease the level or effect of infigratinib by inhibition of GI absorption. Applies only to oral form of both agents. Avoid or Use Alternate Drug. If use with an acid-reducing agent cannot be avoided, administer infigratinib 2 hr before and after administration of a locally-acting antacid.

• ketoconazole

  calcium carbonate will decrease the level or effect of ketoconazole by increasing gastric pH. Applies only to oral form of both agents. Avoid or Use Alternate Drug.

• minocycline

  calcium carbonate, minocycline. Either decreases levels of the other by inhibition of GI absorption. Applies only to oral form of both agents. Avoid or Use Alternate Drug. Separate by 2 hours.

• nimodipine

  calcium carbonate will increase the level or effect of nimodipine by increasing gastric pH. Applies only to oral form of both agents. Avoid or Use Alternate Drug.

• nisoldipine

  calcium carbonate will increase the level or effect of nisoldipine by increasing gastric pH. Applies only to oral form of both agents. Avoid or Use Alternate Drug.

• nitrendipine

  calcium carbonate will increase the level or effect of nitrendipine by increasing gastric pH. Applies only to oral form of both agents. Avoid or Use Alternate Drug.

• oxytetracycline

  calcium carbonate, oxytetracycline. Either decreases levels of the other by inhibition of GI absorption. Applies only to oral form of both agents. Avoid or Use Alternate Drug. Separate by 2 hours.

• pazopanib

  calcium carbonate will decrease the level or effect of pazopanib by increasing gastric pH. Applies only to oral form of both agents. Avoid or Use Alternate Drug. Avoid coadministration of pazopanib with drugs that raise gastric pH; may use short-acting antacids in place of PPIs and H2 antagonists, but separate antacid and pazopanib dosing by several hours

• ponatinib

  calcium carbonate decreases levels of ponatinib by increasing gastric pH. Applies only to oral form of both agents. Avoid or Use Alternate Drug.

• sotorasib

  calcium carbonate will decrease the level or effect of sotorasib by inhibition of GI absorption. Applies only to oral form of both agents. Avoid or Use Alternate Drug. If use with an acid-reducing agent cannot be avoided, administer sotorasib 4 hr before or 10 hr after administration of a locally-acting antacid.

• tetracycline

  calcium carbonate, tetracycline. Either decreases levels of the other by inhibition of GI absorption. Applies only to oral form of both agents. Avoid or Use Alternate Drug. Separate by 2 hours.

Monitor Closely (135)

• acalabrutinib

  calcium carbonate decreases levels of acalabrutinib by increasing gastric pH. Applies only to oral form of both agents. Modify Therapy/Monitor Closely. Acalabrutinib solubility decreases with increasing gastric pH. Separate dosing by at least 2 hr between administration of antacids and acalabrutinib.

• acebutolol

  calcium carbonate decreases effects of acebutolol by unspecified interaction mechanism. Use Caution/Monitor.
  
  calcium carbonate decreases levels of acebutolol by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Separate by 2 hours.

• alendronate

  calcium carbonate decreases levels of alendronate by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Separate by 30 minutes.

• allopurinol

  calcium carbonate decreases levels of allopurinol by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Separate by 2 hours.

• amantadine

  calcium carbonate will increase the level or effect of amantadine by Other (see comment). Modify Therapy/Monitor Closely. Urine pH changes towards alkalinic conditions may lead to an accumulation of amantadine with a possible increase in adverse reactions. Monitor for adverse reactions of amantadine.

• amlodipine

  calcium carbonate decreases effects of amlodipine by pharmacodynamic antagonism. Use Caution/Monitor.

• atenolol

  calcium carbonate decreases effects of atenolol by unspecified interaction mechanism. Use Caution/Monitor.
  
  calcium carbonate decreases levels of atenolol by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Separate by 2 hours.

• azithromycin

  calcium carbonate decreases levels of azithromycin by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Separate by 2 hours.

• bearberry

  calcium carbonate will increase the level or effect of bearberry by passive renal tubular reabsorption - basic urine. Use Caution/Monitor.

• benazepril

  calcium carbonate decreases effects of benazepril by unspecified interaction mechanism. Use Caution/Monitor.

• benzphetamine

  calcium carbonate will increase the level or effect of benzphetamine by passive renal tubular reabsorption - basic urine. Use Caution/Monitor.

• betaxolol

  calcium carbonate decreases effects of betaxolol by unspecified interaction mechanism. Use Caution/Monitor.
  
  calcium carbonate decreases levels of betaxolol by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Separate by 2 hours.

• bictegravir

  calcium carbonate will decrease the level or effect of bictegravir by cation binding in GI tract. Modify Therapy/Monitor Closely. Bictegravir can be taken under fasting conditions 2 hr before antacids containing calcium. However, bictegravir and supplements containing calcium can be taken together with food. Routine administration of bictegravir (under fasting conditions) simultaneously with, or 2 hr after, calcium supplements or antacids containing calcium is not recommended.

• bisoprolol

  calcium carbonate decreases effects of bisoprolol by unspecified interaction mechanism. Use Caution/Monitor.
  
  calcium carbonate decreases levels of bisoprolol by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Separate by 2 hours.

• bosutinib

  calcium carbonate decreases levels of bosutinib by increasing gastric pH. Applies only to oral form of both agents. Use Caution/Monitor. Bosutinib displays pH-dependent solubility; may use short-acting antacids with administration separated by 2 hr.

• budesonide

  calcium carbonate decreases effects of budesonide by increasing gastric pH. Applies only to oral form of both agents. Modify Therapy/Monitor Closely. Enteric-coated budesonide dissolves at pH >5.5. Also, dissolution of extended-release budesonide tablets is pH dependent. Coadministration with drugs that increase gastric pH may cause these budesonide products to prematurely dissolve, and possibly affect release properties and absorption of the drug in the duodenum.

• cabotegravir

  calcium carbonate will decrease the level or effect of cabotegravir by cation binding in GI tract. Modify Therapy/Monitor Closely. Administer antacid products at least 2 hr before or 4 hr after taking oral cabotegravir.

• captopril

  calcium carbonate decreases effects of captopril by unspecified interaction mechanism. Use Caution/Monitor. Calcium carbonate may decrease absorption of captopril.

• carbonyl iron

  calcium carbonate will decrease the level or effect of carbonyl iron by increasing gastric pH. Applies only to oral form of both agents. Use Caution/Monitor.

• carvedilol

  calcium carbonate decreases effects of carvedilol by unspecified interaction mechanism. Use Caution/Monitor.
  
  calcium carbonate decreases levels of carvedilol by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Separate by 2 hours.

• cefdinir

  calcium carbonate will decrease the level or effect of cefdinir by increasing gastric pH. Applies only to oral form of both agents. Use Caution/Monitor.

• cefditoren

  calcium carbonate will decrease the level or effect of cefditoren by increasing gastric pH. Applies only to oral form of both agents. Use Caution/Monitor.

• cefpodoxime

  calcium carbonate will decrease the level or effect of cefpodoxime by increasing gastric pH. Applies only to oral form of both agents. Use Caution/Monitor.

• cefuroxime

  calcium carbonate will decrease the level or effect of cefuroxime by increasing gastric pH. Applies only to oral form of both agents. Use Caution/Monitor.

• celecoxib

  calcium carbonate decreases levels of celecoxib by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Separate by 2 hours.

• celiprolol

  calcium carbonate decreases effects of celiprolol by unspecified interaction mechanism. Use Caution/Monitor.
  
  calcium carbonate decreases levels of celiprolol by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Separate by 2 hours.

• chenodiol

  calcium carbonate decreases levels of chenodiol by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Separate by 2 hours.

• chloroquine

  calcium carbonate will decrease the level or effect of chloroquine by cation binding in GI tract. Use Caution/Monitor. Separate doses by at least 4 hr

• ciprofloxacin

  calcium carbonate decreases effects of ciprofloxacin by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Ciprofloxacin should be administered 2 hr before or 6 hr after calcium salts.

• clevidipine

  calcium carbonate decreases effects of clevidipine by pharmacodynamic antagonism. Use Caution/Monitor.

• crizotinib

  calcium carbonate decreases levels of crizotinib by increasing gastric pH. Applies only to oral form of both agents. Use Caution/Monitor. Drugs that elevate the gastric pH may decrease the solubility of crizotinib and subsequently reduce its bioavailability. However, no formal studies have been conducted. .

• cyclosporine

  calcium carbonate decreases levels of cyclosporine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Separate by 2 hours.

• dabrafenib

  calcium carbonate will decrease the level or effect of dabrafenib by increasing gastric pH. Applies only to oral form of both agents. Use Caution/Monitor. Drugs that alter upper GI tract pH (eg, PPIs, H2-blockers, antacids) may decrease dabrafenib solubility and reduce its bioavailability

• deferiprone

  calcium carbonate decreases levels of deferiprone by enhancing GI absorption. Applies only to oral form of both agents. Modify Therapy/Monitor Closely. Deferiprone may bind polyvalent cations (eg, iron, aluminum, and zinc), separate administration by at least 4 hr between deferiprone and other medications (eg, antacids), or supplements containing these polyvalent cations.

• deferoxamine

  deferoxamine decreases levels of calcium carbonate by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Deferoxamine chelates iron; its affinity for other minerals is unknown.

• delafloxacin

  calcium carbonate will decrease the level or effect of delafloxacin by cation binding in GI tract. Modify Therapy/Monitor Closely. Oral delafloxacin form chelates with alkaline earth and transition metal cations. Administer oral delafloxacin at least 2 hr before or 6 hr after these agents.

• dextroamphetamine

  calcium carbonate will increase the level or effect of dextroamphetamine by passive renal tubular reabsorption - basic urine. Use Caution/Monitor.

• digoxin

  calcium carbonate increases effects of digoxin by pharmacodynamic synergism. Use Caution/Monitor.

• diltiazem

  calcium carbonate decreases effects of diltiazem by pharmacodynamic antagonism. Use Caution/Monitor.

• dolutegravir

  calcium carbonate will decrease the level or effect of dolutegravir by cation binding in GI tract. Modify Therapy/Monitor Closely. Administer dolutegravir 2 hr (dolutegravir or abacavir/dolutegravir/lamivudine) or 4 hr (dolutegravir/rilpivirine) before or 6 hr after taking medications containing polyvalent cations.

• elvitegravir

  calcium carbonate will decrease the level or effect of elvitegravir by cation binding in GI tract. Modify Therapy/Monitor Closely. Elvitegravir plasma concentrations are lower with antacids due to the formation of ionic complexes in the GI tract and not due to changes in gastric pH; separate dose from antacid by at least 2 hr

• elvitegravir/cobicistat/emtricitabine/tenofovir DF

  calcium carbonate decreases levels of elvitegravir/cobicistat/emtricitabine/tenofovir DF by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Separate administration from antacids by 2 hr.

• enalapril

  calcium carbonate decreases effects of enalapril by unspecified interaction mechanism. Use Caution/Monitor.

• ephedrine

  calcium carbonate will increase the level or effect of ephedrine by passive renal tubular reabsorption - basic urine. Use Caution/Monitor.

• erythromycin base

  calcium carbonate increases levels of erythromycin base by unknown mechanism. Use Caution/Monitor.

• erythromycin ethylsuccinate

  calcium carbonate increases levels of erythromycin ethylsuccinate by unknown mechanism. Use Caution/Monitor.

• erythromycin lactobionate

  calcium carbonate increases levels of erythromycin lactobionate by unknown mechanism. Use Caution/Monitor.

• erythromycin stearate

  calcium carbonate increases levels of erythromycin stearate by unknown mechanism. Use Caution/Monitor.

• esmolol

  calcium carbonate decreases effects of esmolol by unspecified interaction mechanism. Use Caution/Monitor.
  
  calcium carbonate decreases levels of esmolol by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Separate by 2 hours.

• estramustine

  calcium carbonate decreases levels of estramustine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Patients should take estramustine with water at least 1h before or 2h after meals.

• etidronate

  calcium carbonate decreases levels of etidronate by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Separate by 30 minutes.

• felodipine

  calcium carbonate decreases effects of felodipine by pharmacodynamic antagonism. Use Caution/Monitor.

• ferric maltol

  calcium carbonate will decrease the level or effect of ferric maltol by increasing gastric pH. Applies only to oral form of both agents. Use Caution/Monitor.

• ferrous fumarate

  calcium carbonate will decrease the level or effect of ferrous fumarate by increasing gastric pH. Applies only to oral form of both agents. Use Caution/Monitor.

• ferrous gluconate

  calcium carbonate will decrease the level or effect of ferrous gluconate by increasing gastric pH. Applies only to oral form of both agents. Use Caution/Monitor.

• flecainide

  calcium carbonate will increase the level or effect of flecainide by passive renal tubular reabsorption - basic urine. Use Caution/Monitor.

• fosamprenavir

  calcium carbonate will decrease the level or effect of fosamprenavir by increasing gastric pH. Applies only to oral form of both agents. Use Caution/Monitor.

• fosinopril

  calcium carbonate decreases effects of fosinopril by unspecified interaction mechanism. Use Caution/Monitor.

• gabapentin

  calcium carbonate decreases levels of gabapentin by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Separate by 2 hours.

• gabapentin enacarbil

  calcium carbonate decreases levels of gabapentin enacarbil by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Separate by 2 hours.

• gefitinib

  calcium carbonate decreases levels of gefitinib by increasing gastric pH. Applies only to oral form of both agents. Use Caution/Monitor. Separate gefitinib and antacid doses by at least 6 hr.

• gemifloxacin

  calcium carbonate, gemifloxacin. Either decreases levels of the other by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Separate by 2 hours.

• glipizide

  calcium carbonate will increase the level or effect of glipizide by increasing gastric pH. Applies only to oral form of both agents. Use Caution/Monitor.

• glyburide

  calcium carbonate will increase the level or effect of glyburide by increasing gastric pH. Applies only to oral form of both agents. Use Caution/Monitor.

• ibandronate

  calcium carbonate decreases levels of ibandronate by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Separate by 30 minutes.

• imidapril

  calcium carbonate decreases effects of imidapril by unspecified interaction mechanism. Use Caution/Monitor.

• iron dextran complex

  calcium carbonate will decrease the level or effect of iron dextran complex by increasing gastric pH. Applies only to oral form of both agents. Use Caution/Monitor.

• iron sucrose

  calcium carbonate will decrease the level or effect of iron sucrose by increasing gastric pH. Applies only to oral form of both agents. Use Caution/Monitor.

• isoniazid

  calcium carbonate decreases levels of isoniazid by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Separate by 2 hours.

• isradipine

  calcium carbonate decreases effects of isradipine by pharmacodynamic antagonism. Use Caution/Monitor.

• itraconazole

  calcium carbonate will decrease the level or effect of itraconazole by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Administer acid neutralizing medicines at least 2 hours before or 2 hours after itraconazole.

• ketoconazole

  calcium carbonate decreases levels of ketoconazole by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Separate by 2 hours.

• labetalol

  calcium carbonate decreases effects of labetalol by unspecified interaction mechanism. Use Caution/Monitor.
  
  calcium carbonate decreases levels of labetalol by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Separate by 2 hours.

• lactulose

  calcium carbonate decreases effects of lactulose by pharmacodynamic antagonism. Use Caution/Monitor.

• lanthanum carbonate

  lanthanum carbonate, calcium carbonate. cation binding in GI tract. Use Caution/Monitor. Administer antacid at least 2 hours before or after lanthanum. .

• ledipasvir/sofosbuvir

  calcium carbonate decreases levels of ledipasvir/sofosbuvir by Other (see comment). Use Caution/Monitor. Comment: Ledipasvir solubility decreases as pH increases; drugs that increase gastric pH are expected to decrease levels of ledipasvir; separate antacid and ledipasivr/sofosbuvir administration by 4 hr.

• levofloxacin

  calcium carbonate, levofloxacin. Either decreases levels of the other by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Separate by 2 hours.

• levothyroxine

  calcium carbonate decreases levels of levothyroxine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Separate by 2 hours.

• lisdexamfetamine

  calcium carbonate will increase the level or effect of lisdexamfetamine by passive renal tubular reabsorption - basic urine. Use Caution/Monitor.

• lisinopril

  calcium carbonate decreases effects of lisinopril by unspecified interaction mechanism. Use Caution/Monitor.

• memantine

  calcium carbonate will increase the level or effect of memantine by passive renal tubular reabsorption - basic urine. Use Caution/Monitor.

• methscopolamine

  calcium carbonate decreases levels of methscopolamine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.

• methylphenidate

  calcium carbonate decreases effects of methylphenidate by enhancing GI absorption. Applies only to oral form of both agents. Modify Therapy/Monitor Closely. Since the characteristics of methylphenidate extended release capsules (Ritalin LA) are pH dependent, coadministration of antacids or acid suppressants could alter the release of methylphenidate. Consider separating the administration of the antacid and the methylphenidate extended-release capsules may be avoided.

• metoprolol

  calcium carbonate decreases effects of metoprolol by unspecified interaction mechanism. Use Caution/Monitor.
  
  calcium carbonate decreases levels of metoprolol by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Separate by 2 hours.

• mexiletine

  calcium carbonate will increase the level or effect of mexiletine by passive renal tubular reabsorption - basic urine. Use Caution/Monitor.

• moexipril

  calcium carbonate decreases effects of moexipril by unspecified interaction mechanism. Use Caution/Monitor.

• moxifloxacin

  calcium carbonate, moxifloxacin. Either decreases levels of the other by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Separate by 2 hours.

• mycophenolate

  calcium carbonate will decrease the level or effect of mycophenolate by increasing gastric pH. Applies only to oral form of both agents. Use Caution/Monitor.

• nadolol

  calcium carbonate decreases effects of nadolol by unspecified interaction mechanism. Use Caution/Monitor.
  
  calcium carbonate decreases levels of nadolol by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Separate by 2 hours.

• nebivolol

  calcium carbonate decreases effects of nebivolol by unspecified interaction mechanism. Use Caution/Monitor.
  
  calcium carbonate decreases levels of nebivolol by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Separate by 2 hours.

• neratinib

  calcium carbonate will decrease the level or effect of neratinib by increasing gastric pH. Applies only to oral form of both agents. Modify Therapy/Monitor Closely. Separate antacid and neratinib dosing by 3 hr.

• nicardipine

  calcium carbonate decreases effects of nicardipine by pharmacodynamic antagonism. Use Caution/Monitor.

• nifedipine

  calcium carbonate decreases effects of nifedipine by pharmacodynamic antagonism. Use Caution/Monitor.

• nilotinib

  calcium carbonate decreases levels of nilotinib by increasing gastric pH. Applies only to oral form of both agents. Modify Therapy/Monitor Closely. Avoid this interaction by administering antacids 2 hr after or 2 hr before nilotinib.

• nisoldipine

  calcium carbonate decreases effects of nisoldipine by pharmacodynamic antagonism. Use Caution/Monitor.

• nitrofurantoin

  calcium carbonate decreases levels of nitrofurantoin by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Separate by 2 hours.

• ofloxacin

  calcium carbonate, ofloxacin. Either decreases levels of the other by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Separate by 2 hours.

• omadacycline

  calcium carbonate will decrease the level or effect of omadacycline by inhibition of GI absorption. Applies only to oral form of both agents. Modify Therapy/Monitor Closely. Multivalent cation-containing products may impair absorption of tetracyclines, which may decrease its efficacy. Separate dosing of tetracyclines from these products.

• pamidronate

  calcium carbonate decreases levels of pamidronate by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Separate by 30 minutes.

• pancrelipase

  calcium carbonate decreases effects of pancrelipase by pharmacodynamic antagonism. Use Caution/Monitor. Antacids may negate beneficial effects of enzymes.

• penbutolol

  calcium carbonate decreases effects of penbutolol by unspecified interaction mechanism. Use Caution/Monitor.
  
  calcium carbonate decreases levels of penbutolol by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Separate by 2 hours.

• penicillamine

  calcium carbonate decreases levels of penicillamine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Separate by 2 hours.

• perindopril

  calcium carbonate decreases effects of perindopril by unspecified interaction mechanism. Use Caution/Monitor.

• pexidartinib

  calcium carbonate will decrease the level or effect of pexidartinib by inhibition of GI absorption. Applies only to oral form of both agents. Modify Therapy/Monitor Closely. Separate pexidartinib by 2 hr before or after taking a locally-acting antacid.

• pindolol

  calcium carbonate decreases effects of pindolol by unspecified interaction mechanism. Use Caution/Monitor.
  
  calcium carbonate decreases levels of pindolol by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Separate by 2 hours.

• polysaccharide iron

  calcium carbonate will decrease the level or effect of polysaccharide iron by increasing gastric pH. Applies only to oral form of both agents. Use Caution/Monitor.

• posaconazole

  calcium carbonate will decrease the level or effect of posaconazole by increasing gastric pH. Applies only to oral form of both agents. Use Caution/Monitor.

• potassium phosphates, IV

  calcium carbonate decreases effects of potassium phosphates, IV by cation binding in GI tract. Modify Therapy/Monitor Closely. Calcium decreases serum phosphate concentration by binding dietary phosphate. Use alternatives if available.

• propranolol

  calcium carbonate decreases effects of propranolol by unspecified interaction mechanism. Use Caution/Monitor.
  
  calcium carbonate decreases levels of propranolol by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Separate by 2 hours.

• quinapril

  calcium carbonate decreases effects of quinapril by unspecified interaction mechanism. Use Caution/Monitor.

• quinidine

  calcium carbonate will increase the level or effect of quinidine by passive renal tubular reabsorption - basic urine. Use Caution/Monitor. Elevated quinidine plasma levels, possibly with cardiac conduction disturbances and arrhythmias, may occur.

• ramipril

  calcium carbonate decreases effects of ramipril by unspecified interaction mechanism. Use Caution/Monitor.

• rifampin

  calcium carbonate will decrease the level or effect of rifampin by Other (see comment). Use Caution/Monitor. Concomitant antacid administration may reduce absorption of rifampin; daily doses of rifampin should be given at least 1 hr before ingestion of antacids

• rilpivirine

  calcium carbonate decreases levels of rilpivirine by increasing gastric pH. Applies only to oral form of both agents. Modify Therapy/Monitor Closely. Coadministration of antacids with rilpivirine may cause significant decreases in rilpivirine plasma concentrations because of increased gastric pH. If antacids must be administered, they should be given at least 2 hr before or at least 4 hr after rilpivirine. For the combination product dolutegravir/rilpivirine, antacids should be given at least 4 hr before or at least 6 hr afterwards.

• riociguat

  calcium carbonate decreases levels of riociguat by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Separate administration by at least 1 hour.

• risedronate

  calcium carbonate decreases levels of risedronate by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Separate by 30 minutes.

• rose hips

  calcium carbonate will decrease the level or effect of rose hips by increasing gastric pH. Applies only to oral form of both agents. Use Caution/Monitor.

• rosuvastatin

  calcium carbonate decreases levels of rosuvastatin by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Separate by 2 hours.

• sarecycline

  calcium carbonate will decrease the level or effect of sarecycline by inhibition of GI absorption. Applies only to oral form of both agents. Modify Therapy/Monitor Closely. Multivalent cation-containing products may impair absorption of tetracyclines, which may decrease its efficacy. Separate dosing of tetracyclines from these products.

• sodium phosphates, IV

  calcium carbonate decreases effects of sodium phosphates, IV by cation binding in GI tract. Modify Therapy/Monitor Closely. Calcium decreases serum phosphate concentration by binding dietary phosphate. Use alternatives if available.

• sodium sulfate/?magnesium sulfate/potassium chloride

  sodium sulfate/?magnesium sulfate/potassium chloride increases toxicity of calcium carbonate by Other (see comment). Use Caution/Monitor. Comment: Coadministration with medications that cause fluid and electrolyte abnormalities may increase the risk of adverse events of seizure, arrhythmias, and renal impairment.

• sodium sulfate/potassium sulfate/magnesium sulfate

  sodium sulfate/potassium sulfate/magnesium sulfate increases toxicity of calcium carbonate by Other (see comment). Use Caution/Monitor. Comment: Coadministration with medications that cause fluid and electrolyte abnormalities may increase the risk of adverse events of seizure, arrhythmias, and renal impairment.

• sofosbuvir/velpatasvir

  calcium carbonate will decrease the level or effect of sofosbuvir/velpatasvir by increasing gastric pH. Applies only to oral form of both agents. Modify Therapy/Monitor Closely. Velpatasvir solubility decreases as gastric pH increases (practically insoluble at pH >5). Separate administration of sofosbuvir/velpatasvir from antacids by at least 4 hr.

• sotalol

  calcium carbonate decreases effects of sotalol by unspecified interaction mechanism. Use Caution/Monitor.
  
  calcium carbonate decreases levels of sotalol by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Separate by 2 hours.

• squill

  calcium carbonate increases toxicity of squill by unspecified interaction mechanism. Use Caution/Monitor.

• strontium ranelate

  calcium carbonate decreases levels of strontium ranelate by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Applies to oral form of calcium. Separate by 2 hr.

• tiludronate

  calcium carbonate decreases levels of tiludronate by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Separate by 30 minutes.

• timolol

  calcium carbonate decreases effects of timolol by unspecified interaction mechanism. Use Caution/Monitor.
  
  calcium carbonate decreases levels of timolol by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Separate by 2 hours.

• tolbutamide

  calcium carbonate will increase the level or effect of tolbutamide by increasing gastric pH. Applies only to oral form of both agents. Use Caution/Monitor.

• trandolapril

  calcium carbonate decreases effects of trandolapril by unspecified interaction mechanism. Use Caution/Monitor.

• ursodiol

  calcium carbonate decreases effects of ursodiol by pharmacodynamic antagonism. Use Caution/Monitor.

• verapamil

  calcium carbonate decreases effects of verapamil by pharmacodynamic antagonism. Use Caution/Monitor.

• vismodegib

  calcium carbonate will decrease the level or effect of vismodegib by Other (see comment). Use Caution/Monitor. Drugs that increase gastric pH alter vismodegib solubility and therefore reduce bioavailability; effect on efficacy unknown

• vitamin D

  vitamin D, calcium carbonate. Other (see comment). Use Caution/Monitor. Comment: The concurrent use of vitamin D with calcium salts is generally beneficial; in some patients this combination may result in hypercalcemia.

• zoledronic acid

  calcium carbonate decreases levels of zoledronic acid by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Separate by 30 minutes.

Minor (64)

• amikacin

  amikacin decreases levels of calcium carbonate by inhibition of GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown.

• amiloride

  amiloride decreases levels of calcium carbonate by increasing renal clearance. Minor/Significance Unknown.

• aspirin

  calcium carbonate, aspirin. Mechanism: passive renal tubular reabsorption due to increased pH. Minor/Significance Unknown. Salicylate levels increased at moderate doses; salicylate levels decreased at large doses (d/t increased renal excretion of unchanged salicylic acid).

• aspirin rectal

  calcium carbonate, aspirin rectal. Mechanism: passive renal tubular reabsorption due to increased pH. Minor/Significance Unknown. Salicylate levels increased at moderate doses; salicylate levels decreased at large doses (d/t increased renal excretion of unchanged salicylic acid).

• aspirin/citric acid/sodium bicarbonate

  calcium carbonate, aspirin/citric acid/sodium bicarbonate. Mechanism: passive renal tubular reabsorption due to increased pH. Minor/Significance Unknown. Salicylate levels increased at moderate doses; salicylate levels decreased at large doses (d/t increased renal excretion of unchanged salicylic acid).

• balsalazide

  calcium carbonate, balsalazide. Mechanism: passive renal tubular reabsorption due to increased pH. Minor/Significance Unknown. Salicylate levels increased at moderate doses; salicylate levels decreased at large doses (d/t increased renal excretion of unchanged salicylic acid).

• bendroflumethiazide

  bendroflumethiazide increases levels of calcium carbonate by decreasing renal clearance. Minor/Significance Unknown. Risk of alkalosis, hypercalcemia.

• blessed thistle

  blessed thistle decreases effects of calcium carbonate by pharmacodynamic antagonism. Minor/Significance Unknown. Theoretical interaction.

• budesonide

  budesonide decreases levels of calcium carbonate by increasing elimination. Minor/Significance Unknown.

• bumetanide

  bumetanide decreases levels of calcium carbonate by increasing renal clearance. Minor/Significance Unknown.

• caffeine

  caffeine decreases levels of calcium carbonate by increasing renal clearance. Minor/Significance Unknown.

• calcitriol topical

  calcitriol topical increases levels of calcium carbonate by pharmacodynamic synergism. Minor/Significance Unknown. Topical calcitriol may lead to hypercalcemia.

• carbonyl iron

  calcium carbonate decreases levels of carbonyl iron by inhibition of GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown.
  
  carbonyl iron increases levels of calcium carbonate by enhancing GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown.

• chlorothiazide

  chlorothiazide increases levels of calcium carbonate by decreasing renal clearance. Minor/Significance Unknown. Risk of alkalosis, hypercalcemia.

• chlorthalidone

  chlorthalidone increases levels of calcium carbonate by decreasing renal clearance. Minor/Significance Unknown. Risk of alkalosis, hypercalcemia.

• choline magnesium trisalicylate

  calcium carbonate, choline magnesium trisalicylate. Mechanism: passive renal tubular reabsorption due to increased pH. Minor/Significance Unknown. Salicylate levels increased at moderate doses; salicylate levels decreased at large doses (d/t increased renal excretion of unchanged salicylic acid).

• chromium

  calcium carbonate decreases levels of chromium by inhibition of GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown. Separate by 2 hours.

• cortisone

  cortisone decreases levels of calcium carbonate by increasing elimination. Minor/Significance Unknown.

• cyclopenthiazide

  cyclopenthiazide increases levels of calcium carbonate by decreasing renal clearance. Minor/Significance Unknown. Risk of alkalosis, hypercalcemia.

• deflazacort

  deflazacort decreases levels of calcium carbonate by increasing elimination. Minor/Significance Unknown.

• devil's claw

  devil's claw decreases effects of calcium carbonate by pharmacodynamic antagonism. Minor/Significance Unknown.

• dexamethasone

  dexamethasone decreases levels of calcium carbonate by increasing elimination. Minor/Significance Unknown.

• diflunisal

  calcium carbonate, diflunisal. Mechanism: passive renal tubular reabsorption due to increased pH. Minor/Significance Unknown. Salicylate levels increased at moderate doses; salicylate levels decreased at large doses (d/t increased renal excretion of unchanged salicylic acid).

• drospirenone

  drospirenone decreases levels of calcium carbonate by increasing renal clearance. Minor/Significance Unknown.

• ethacrynic acid

  ethacrynic acid decreases levels of calcium carbonate by increasing renal clearance. Minor/Significance Unknown.

• ferric maltol

  ferric maltol increases levels of calcium carbonate by enhancing GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown.
  
  calcium carbonate decreases levels of ferric maltol by inhibition of GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown.

• ferrous fumarate

  calcium carbonate decreases levels of ferrous fumarate by inhibition of GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown.
  
  ferrous fumarate increases levels of calcium carbonate by enhancing GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown.

• ferrous gluconate

  ferrous gluconate increases levels of calcium carbonate by enhancing GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown.
  
  calcium carbonate decreases levels of ferrous gluconate by inhibition of GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown.

• ferrous sulfate

  ferrous sulfate increases levels of calcium carbonate by enhancing GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown.

• fludrocortisone

  fludrocortisone decreases levels of calcium carbonate by increasing elimination. Minor/Significance Unknown.

• furosemide

  furosemide decreases levels of calcium carbonate by increasing renal clearance. Minor/Significance Unknown.

• gentamicin

  gentamicin decreases levels of calcium carbonate by inhibition of GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown.

• hydrochlorothiazide

  hydrochlorothiazide increases levels of calcium carbonate by decreasing renal clearance. Minor/Significance Unknown. Risk of alkalosis, hypercalcemia.

• hydrocortisone

  hydrocortisone decreases levels of calcium carbonate by increasing elimination. Minor/Significance Unknown.

• indapamide

  indapamide increases levels of calcium carbonate by decreasing renal clearance. Minor/Significance Unknown. Risk of alkalosis, hypercalcemia.

• iron dextran complex

  calcium carbonate decreases levels of iron dextran complex by inhibition of GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown.
  
  iron dextran complex increases levels of calcium carbonate by enhancing GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown.

• iron sucrose

  calcium carbonate decreases levels of iron sucrose by inhibition of GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown.
  
  iron sucrose increases levels of calcium carbonate by enhancing GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown.

• isoniazid

  isoniazid decreases levels of calcium carbonate by inhibition of GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown.

• isotretinoin

  isotretinoin increases levels of calcium carbonate by enhancing GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown.

• lily of the valley

  calcium carbonate increases effects of lily of the valley by unspecified interaction mechanism. Minor/Significance Unknown.

• manganese

  calcium carbonate, manganese. Either decreases levels of the other by inhibition of GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown. Separate by 2 hours.

• mesalamine

  calcium carbonate, mesalamine. Mechanism: passive renal tubular reabsorption due to increased pH. Minor/Significance Unknown. Salicylate levels increased at moderate doses; salicylate levels decreased at large doses (d/t increased renal excretion of unchanged salicylic acid).

• methyclothiazide

  methyclothiazide increases levels of calcium carbonate by decreasing renal clearance. Minor/Significance Unknown. Risk of alkalosis, hypercalcemia.

• methylprednisolone

  methylprednisolone decreases levels of calcium carbonate by increasing elimination. Minor/Significance Unknown.

• metolazone

  metolazone increases levels of calcium carbonate by decreasing renal clearance. Minor/Significance Unknown. Risk of alkalosis, hypercalcemia.

• neomycin PO

  neomycin PO decreases levels of calcium carbonate by inhibition of GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown.

• paromomycin

  paromomycin decreases levels of calcium carbonate by inhibition of GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown.

• polysaccharide iron

  calcium carbonate decreases levels of polysaccharide iron by inhibition of GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown.
  
  polysaccharide iron increases levels of calcium carbonate by enhancing GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown.

• prednisolone

  prednisolone decreases levels of calcium carbonate by increasing elimination. Minor/Significance Unknown.

• prednisone

  prednisone decreases levels of calcium carbonate by increasing elimination. Minor/Significance Unknown.

• rose hips

  calcium carbonate decreases levels of rose hips by inhibition of GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown.
  
  rose hips increases levels of calcium carbonate by enhancing GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown.

• salicylates (non-asa)

  calcium carbonate, salicylates (non-asa). Mechanism: passive renal tubular reabsorption due to increased pH. Minor/Significance Unknown. Salicylate levels increased at moderate doses; salicylate levels decreased at large doses (d/t increased renal excretion of unchanged salicylic acid).

• salsalate

  calcium carbonate, salsalate. Mechanism: passive renal tubular reabsorption due to increased pH. Minor/Significance Unknown. Salicylate levels increased at moderate doses; salicylate levels decreased at large doses (d/t increased renal excretion of unchanged salicylic acid).

• shark cartilage

  calcium carbonate, shark cartilage. pharmacodynamic synergism. Minor/Significance Unknown. May lead to hypercalcemia (theoretical).

• sodium polystyrene sulfonate

  sodium polystyrene sulfonate increases levels of calcium carbonate by decreasing renal clearance. Minor/Significance Unknown. Risk of alkalosis.

• spironolactone

  spironolactone decreases levels of calcium carbonate by increasing renal clearance. Minor/Significance Unknown.

• streptomycin

  streptomycin decreases levels of calcium carbonate by inhibition of GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown.

• sulfasalazine

  calcium carbonate, sulfasalazine. Mechanism: passive renal tubular reabsorption due to increased pH. Minor/Significance Unknown. Salicylate levels increased at moderate doses; salicylate levels decreased at large doses (d/t increased renal excretion of unchanged salicylic acid).

• teriparatide

  teriparatide increases levels of calcium carbonate by pharmacodynamic synergism. Minor/Significance Unknown.

• tobramycin

  tobramycin decreases levels of calcium carbonate by inhibition of GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown.

• torsemide

  torsemide decreases levels of calcium carbonate by increasing renal clearance. Minor/Significance Unknown.

• triamcinolone acetonide injectable suspension

  triamcinolone acetonide injectable suspension decreases levels of calcium carbonate by increasing elimination. Minor/Significance Unknown.

• triamterene

  triamterene decreases levels of calcium carbonate by increasing renal clearance. Minor/Significance Unknown.

• willow bark

  calcium carbonate, willow bark. Mechanism: passive renal tubular reabsorption due to increased pH. Minor/Significance Unknown. Salicylate levels increased at moderate doses; salicylate levels decreased at large doses (d/t increased renal excretion of unchanged salicylic acid).

• acalabrutinib

  Monitor Closely (1)calcium carbonate decreases levels of acalabrutinib by increasing gastric pH. Applies only to oral form of both agents. Modify Therapy/Monitor Closely. Acalabrutinib solubility decreases with increasing gastric pH. Separate dosing by at least 2 hr between administration of antacids and acalabrutinib.

• acebutolol

  Monitor Closely (2)calcium carbonate decreases effects of acebutolol by unspecified interaction mechanism. Use Caution/Monitor.
  
  calcium carbonate decreases levels of acebutolol by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Separate by 2 hours.

• alendronate

  Monitor Closely (1)calcium carbonate decreases levels of alendronate by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Separate by 30 minutes.

• allopurinol

  Monitor Closely (1)calcium carbonate decreases levels of allopurinol by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Separate by 2 hours.

• amantadine

  Monitor Closely (1)calcium carbonate will increase the level or effect of amantadine by Other (see comment). Modify Therapy/Monitor Closely. Urine pH changes towards alkalinic conditions may lead to an accumulation of amantadine with a possible increase in adverse reactions. Monitor for adverse reactions of amantadine.

• amikacin

  Minor (1)amikacin decreases levels of calcium carbonate by inhibition of GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown.

• amiloride

  Minor (1)amiloride decreases levels of calcium carbonate by increasing renal clearance. Minor/Significance Unknown.

• amlodipine

  Monitor Closely (1)calcium carbonate decreases effects of amlodipine by pharmacodynamic antagonism. Use Caution/Monitor.

• aspirin

  Minor (1)calcium carbonate, aspirin. Mechanism: passive renal tubular reabsorption due to increased pH. Minor/Significance Unknown. Salicylate levels increased at moderate doses; salicylate levels decreased at large doses (d/t increased renal excretion of unchanged salicylic acid).

• aspirin rectal

  Minor (1)calcium carbonate, aspirin rectal. Mechanism: passive renal tubular reabsorption due to increased pH. Minor/Significance Unknown. Salicylate levels increased at moderate doses; salicylate levels decreased at large doses (d/t increased renal excretion of unchanged salicylic acid).

• aspirin/citric acid/sodium bicarbonate

  Minor (1)calcium carbonate, aspirin/citric acid/sodium bicarbonate. Mechanism: passive renal tubular reabsorption due to increased pH. Minor/Significance Unknown. Salicylate levels increased at moderate doses; salicylate levels decreased at large doses (d/t increased renal excretion of unchanged salicylic acid).

• atazanavir

  Serious - Use Alternative (1)calcium carbonate will decrease the level or effect of atazanavir by increasing gastric pH. Applies only to oral form of both agents. Avoid or Use Alternate Drug. Atazanavir solubility decreases as pH increases. Reduced plasma concentrations of atazanavir are expected if antacids or buffered medications are coadministered. Administer atazanavir 2 hr before or 1 hr after these medications.

• atenolol

  Monitor Closely (2)calcium carbonate decreases effects of atenolol by unspecified interaction mechanism. Use Caution/Monitor.
  
  calcium carbonate decreases levels of atenolol by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Separate by 2 hours.

• azithromycin

  Monitor Closely (1)calcium carbonate decreases levels of azithromycin by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Separate by 2 hours.

• baloxavir marboxil

  Serious - Use Alternative (1)calcium carbonate will decrease the level or effect of baloxavir marboxil by cation binding in GI tract. Avoid or Use Alternate Drug. Baloxavir may bind to polyvalent cations resulting in decreased absorption. Studies in monkeys showed concurrent use with calcium, aluminum, or iron caused significantly decreased plasma levels. Human studies not conducted.

• balsalazide

  Minor (1)calcium carbonate, balsalazide. Mechanism: passive renal tubular reabsorption due to increased pH. Minor/Significance Unknown. Salicylate levels increased at moderate doses; salicylate levels decreased at large doses (d/t increased renal excretion of unchanged salicylic acid).

• bearberry

  Monitor Closely (1)calcium carbonate will increase the level or effect of bearberry by passive renal tubular reabsorption - basic urine. Use Caution/Monitor.

• benazepril

  Monitor Closely (1)calcium carbonate decreases effects of benazepril by unspecified interaction mechanism. Use Caution/Monitor.

• bendroflumethiazide

  Minor (1)bendroflumethiazide increases levels of calcium carbonate by decreasing renal clearance. Minor/Significance Unknown. Risk of alkalosis, hypercalcemia.

• benzphetamine

  Monitor Closely (1)calcium carbonate will increase the level or effect of benzphetamine by passive renal tubular reabsorption - basic urine. Use Caution/Monitor.

• betaxolol

  Monitor Closely (2)calcium carbonate decreases effects of betaxolol by unspecified interaction mechanism. Use Caution/Monitor.
  
  calcium carbonate decreases levels of betaxolol by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Separate by 2 hours.

• bictegravir

  Monitor Closely (1)calcium carbonate will decrease the level or effect of bictegravir by cation binding in GI tract. Modify Therapy/Monitor Closely. Bictegravir can be taken under fasting conditions 2 hr before antacids containing calcium. However, bictegravir and supplements containing calcium can be taken together with food. Routine administration of bictegravir (under fasting conditions) simultaneously with, or 2 hr after, calcium supplements or antacids containing calcium is not recommended.

• bisoprolol

  Monitor Closely (2)calcium carbonate decreases effects of bisoprolol by unspecified interaction mechanism. Use Caution/Monitor.
  
  calcium carbonate decreases levels of bisoprolol by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Separate by 2 hours.

• blessed thistle

  Minor (1)blessed thistle decreases effects of calcium carbonate by pharmacodynamic antagonism. Minor/Significance Unknown. Theoretical interaction.

• bosutinib

  Monitor Closely (1)calcium carbonate decreases levels of bosutinib by increasing gastric pH. Applies only to oral form of both agents. Use Caution/Monitor. Bosutinib displays pH-dependent solubility; may use short-acting antacids with administration separated by 2 hr.

• budesonide

  Monitor Closely (1)calcium carbonate decreases effects of budesonide by increasing gastric pH. Applies only to oral form of both agents. Modify Therapy/Monitor Closely. Enteric-coated budesonide dissolves at pH >5.5. Also, dissolution of extended-release budesonide tablets is pH dependent. Coadministration with drugs that increase gastric pH may cause these budesonide products to prematurely dissolve, and possibly affect release properties and absorption of the drug in the duodenum.Minor (1)budesonide decreases levels of calcium carbonate by increasing elimination. Minor/Significance Unknown.

• bumetanide

  Minor (1)bumetanide decreases levels of calcium carbonate by increasing renal clearance. Minor/Significance Unknown.

• cabotegravir

  Monitor Closely (1)calcium carbonate will decrease the level or effect of cabotegravir by cation binding in GI tract. Modify Therapy/Monitor Closely. Administer antacid products at least 2 hr before or 4 hr after taking oral cabotegravir.

• caffeine

  Minor (1)caffeine decreases levels of calcium carbonate by increasing renal clearance. Minor/Significance Unknown.

• calcitriol topical

  Minor (1)calcitriol topical increases levels of calcium carbonate by pharmacodynamic synergism. Minor/Significance Unknown. Topical calcitriol may lead to hypercalcemia.

• captopril

  Monitor Closely (1)calcium carbonate decreases effects of captopril by unspecified interaction mechanism. Use Caution/Monitor. Calcium carbonate may decrease absorption of captopril.

• carbonyl iron

  Monitor Closely (1)calcium carbonate will decrease the level or effect of carbonyl iron by increasing gastric pH. Applies only to oral form of both agents. Use Caution/Monitor.Minor (2)calcium carbonate decreases levels of carbonyl iron by inhibition of GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown.
  
  carbonyl iron increases levels of calcium carbonate by enhancing GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown.

• carvedilol

  Monitor Closely (2)calcium carbonate decreases effects of carvedilol by unspecified interaction mechanism. Use Caution/Monitor.
  
  calcium carbonate decreases levels of carvedilol by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Separate by 2 hours.

• cefdinir

  Monitor Closely (1)calcium carbonate will decrease the level or effect of cefdinir by increasing gastric pH. Applies only to oral form of both agents. Use Caution/Monitor.

• cefditoren

  Monitor Closely (1)calcium carbonate will decrease the level or effect of cefditoren by increasing gastric pH. Applies only to oral form of both agents. Use Caution/Monitor.

• cefpodoxime

  Monitor Closely (1)calcium carbonate will decrease the level or effect of cefpodoxime by increasing gastric pH. Applies only to oral form of both agents. Use Caution/Monitor.

• ceftriaxone

  Contraindicated (1)ceftriaxone, calcium carbonate. Other (see comment). Contraindicated. Comment: Do not use ANY calcium containing solutions (including Ringer or Harmann solutions) in combination with IV ceftriaxone; risk of potentially fatal particulate precipitation in lungs, kidneys. Separate by at least 48 hrs.

• cefuroxime

  Monitor Closely (1)calcium carbonate will decrease the level or effect of cefuroxime by increasing gastric pH. Applies only to oral form of both agents. Use Caution/Monitor.

• celecoxib

  Monitor Closely (1)calcium carbonate decreases levels of celecoxib by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Separate by 2 hours.

• celiprolol

  Monitor Closely (2)calcium carbonate decreases effects of celiprolol by unspecified interaction mechanism. Use Caution/Monitor.
  
  calcium carbonate decreases levels of celiprolol by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Separate by 2 hours.

• chenodiol

  Monitor Closely (1)calcium carbonate decreases levels of chenodiol by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Separate by 2 hours.

• chloroquine

  Monitor Closely (1)calcium carbonate will decrease the level or effect of chloroquine by cation binding in GI tract. Use Caution/Monitor. Separate doses by at least 4 hr

• chlorothiazide

  Minor (1)chlorothiazide increases levels of calcium carbonate by decreasing renal clearance. Minor/Significance Unknown. Risk of alkalosis, hypercalcemia.

• chlorthalidone

  Minor (1)chlorthalidone increases levels of calcium carbonate by decreasing renal clearance. Minor/Significance Unknown. Risk of alkalosis, hypercalcemia.

• choline magnesium trisalicylate

  Minor (1)calcium carbonate, choline magnesium trisalicylate. Mechanism: passive renal tubular reabsorption due to increased pH. Minor/Significance Unknown. Salicylate levels increased at moderate doses; salicylate levels decreased at large doses (d/t increased renal excretion of unchanged salicylic acid).

• chromium

  Minor (1)calcium carbonate decreases levels of chromium by inhibition of GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown. Separate by 2 hours.

• ciprofloxacin

  Monitor Closely (1)calcium carbonate decreases effects of ciprofloxacin by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Ciprofloxacin should be administered 2 hr before or 6 hr after calcium salts.

• clevidipine

  Monitor Closely (1)calcium carbonate decreases effects of clevidipine by pharmacodynamic antagonism. Use Caution/Monitor.

• cortisone

  Minor (1)cortisone decreases levels of calcium carbonate by increasing elimination. Minor/Significance Unknown.

• crizotinib

  Monitor Closely (1)calcium carbonate decreases levels of crizotinib by increasing gastric pH. Applies only to oral form of both agents. Use Caution/Monitor. Drugs that elevate the gastric pH may decrease the solubility of crizotinib and subsequently reduce its bioavailability. However, no formal studies have been conducted. .

• cyclopenthiazide

  Minor (1)cyclopenthiazide increases levels of calcium carbonate by decreasing renal clearance. Minor/Significance Unknown. Risk of alkalosis, hypercalcemia.

• cyclosporine

  Monitor Closely (1)calcium carbonate decreases levels of cyclosporine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Separate by 2 hours.

• dabrafenib

  Monitor Closely (1)calcium carbonate will decrease the level or effect of dabrafenib by increasing gastric pH. Applies only to oral form of both agents. Use Caution/Monitor. Drugs that alter upper GI tract pH (eg, PPIs, H2-blockers, antacids) may decrease dabrafenib solubility and reduce its bioavailability

• dapsone

  Serious - Use Alternative (1)calcium carbonate will decrease the level or effect of dapsone by increasing gastric pH. Applies only to oral form of both agents. Avoid or Use Alternate Drug.

• dasatinib

  Serious - Use Alternative (1)calcium carbonate will decrease the level or effect of dasatinib by increasing gastric pH. Applies only to oral form of both agents. Avoid or Use Alternate Drug.

• deferiprone

  Monitor Closely (1)calcium carbonate decreases levels of deferiprone by enhancing GI absorption. Applies only to oral form of both agents. Modify Therapy/Monitor Closely. Deferiprone may bind polyvalent cations (eg, iron, aluminum, and zinc), separate administration by at least 4 hr between deferiprone and other medications (eg, antacids), or supplements containing these polyvalent cations.

• deferoxamine

  Monitor Closely (1)deferoxamine decreases levels of calcium carbonate by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Deferoxamine chelates iron; its affinity for other minerals is unknown.

• deflazacort

  Minor (1)deflazacort decreases levels of calcium carbonate by increasing elimination. Minor/Significance Unknown.

• delafloxacin

  Monitor Closely (1)calcium carbonate will decrease the level or effect of delafloxacin by cation binding in GI tract. Modify Therapy/Monitor Closely. Oral delafloxacin form chelates with alkaline earth and transition metal cations. Administer oral delafloxacin at least 2 hr before or 6 hr after these agents.

• demeclocycline

  Serious - Use Alternative (1)calcium carbonate, demeclocycline. Either decreases levels of the other by inhibition of GI absorption. Applies only to oral form of both agents. Avoid or Use Alternate Drug. Separate by 2 hours.

• devil's claw

  Minor (1)devil's claw decreases effects of calcium carbonate by pharmacodynamic antagonism. Minor/Significance Unknown.

• dexamethasone

  Minor (1)dexamethasone decreases levels of calcium carbonate by increasing elimination. Minor/Significance Unknown.

• dextroamphetamine

  Monitor Closely (1)calcium carbonate will increase the level or effect of dextroamphetamine by passive renal tubular reabsorption - basic urine. Use Caution/Monitor.

• diflunisal

  Minor (1)calcium carbonate, diflunisal. Mechanism: passive renal tubular reabsorption due to increased pH. Minor/Significance Unknown. Salicylate levels increased at moderate doses; salicylate levels decreased at large doses (d/t increased renal excretion of unchanged salicylic acid).

• digoxin

  Monitor Closely (1)calcium carbonate increases effects of digoxin by pharmacodynamic synergism. Use Caution/Monitor.Serious - Use Alternative (1)calcium carbonate will increase the level or effect of digoxin by increasing gastric pH. Applies only to oral form of both agents. Avoid or Use Alternate Drug.

• diltiazem

  Monitor Closely (1)calcium carbonate decreases effects of diltiazem by pharmacodynamic antagonism. Use Caution/Monitor.

• dolutegravir

  Monitor Closely (1)calcium carbonate will decrease the level or effect of dolutegravir by cation binding in GI tract. Modify Therapy/Monitor Closely. Administer dolutegravir 2 hr (dolutegravir or abacavir/dolutegravir/lamivudine) or 4 hr (dolutegravir/rilpivirine) before or 6 hr after taking medications containing polyvalent cations.

• doxycycline

  Serious - Use Alternative (1)calcium carbonate, doxycycline. Either decreases levels of the other by inhibition of GI absorption. Applies only to oral form of both agents. Avoid or Use Alternate Drug. Separate by 2 hours.

• drospirenone

  Minor (1)drospirenone decreases levels of calcium carbonate by increasing renal clearance. Minor/Significance Unknown.

• eltrombopag

  Serious - Use Alternative (1)calcium carbonate decreases levels of eltrombopag by inhibition of GI absorption. Applies only to oral form of both agents. Contraindicated. Separate by at least 4 hours.

• elvitegravir

  Monitor Closely (1)calcium carbonate will decrease the level or effect of elvitegravir by cation binding in GI tract. Modify Therapy/Monitor Closely. Elvitegravir plasma concentrations are lower with antacids due to the formation of ionic complexes in the GI tract and not due to changes in gastric pH; separate dose from antacid by at least 2 hr

• elvitegravir/cobicistat/emtricitabine/tenofovir DF

  Monitor Closely (1)calcium carbonate decreases levels of elvitegravir/cobicistat/emtricitabine/tenofovir DF by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Separate administration from antacids by 2 hr.

• enalapril

  Monitor Closely (1)calcium carbonate decreases effects of enalapril by unspecified interaction mechanism. Use Caution/Monitor.

• ephedrine

  Monitor Closely (1)calcium carbonate will increase the level or effect of ephedrine by passive renal tubular reabsorption - basic urine. Use Caution/Monitor.

• erdafitinib

  Serious - Use Alternative (1)calcium carbonate, erdafitinib. Other (see comment). Avoid or Use Alternate Drug. Comment: Avoid coadministration during initial dosing adjustment period (ie, first 21 days). Increases in serum phosphate levels are a pharmacodynamic effect of FGFR inhibition. Serum phosphate binders may obscure decisions regarding initial dosage increase.

• erythromycin base

  Monitor Closely (1)calcium carbonate increases levels of erythromycin base by unknown mechanism. Use Caution/Monitor.

• erythromycin ethylsuccinate

  Monitor Closely (1)calcium carbonate increases levels of erythromycin ethylsuccinate by unknown mechanism. Use Caution/Monitor.

• erythromycin lactobionate

  Monitor Closely (1)calcium carbonate increases levels of erythromycin lactobionate by unknown mechanism. Use Caution/Monitor.

• erythromycin stearate

  Monitor Closely (1)calcium carbonate increases levels of erythromycin stearate by unknown mechanism. Use Caution/Monitor.

• esmolol

  Monitor Closely (2)calcium carbonate decreases effects of esmolol by unspecified interaction mechanism. Use Caution/Monitor.
  
  calcium carbonate decreases levels of esmolol by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Separate by 2 hours.

• estramustine

  Monitor Closely (1)calcium carbonate decreases levels of estramustine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Patients should take estramustine with water at least 1h before or 2h after meals.

• ethacrynic acid

  Minor (1)ethacrynic acid decreases levels of calcium carbonate by increasing renal clearance. Minor/Significance Unknown.

• etidronate

  Monitor Closely (1)calcium carbonate decreases levels of etidronate by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Separate by 30 minutes.

• felodipine

  Monitor Closely (1)calcium carbonate decreases effects of felodipine by pharmacodynamic antagonism. Use Caution/Monitor.

• ferric maltol

  Monitor Closely (1)calcium carbonate will decrease the level or effect of ferric maltol by increasing gastric pH. Applies only to oral form of both agents. Use Caution/Monitor.Minor (2)ferric maltol increases levels of calcium carbonate by enhancing GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown.
  
  calcium carbonate decreases levels of ferric maltol by inhibition of GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown.

• ferrous fumarate

  Monitor Closely (1)calcium carbonate will decrease the level or effect of ferrous fumarate by increasing gastric pH. Applies only to oral form of both agents. Use Caution/Monitor.Minor (2)calcium carbonate decreases levels of ferrous fumarate by inhibition of GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown.
  
  ferrous fumarate increases levels of calcium carbonate by enhancing GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown.

• ferrous gluconate

  Monitor Closely (1)calcium carbonate will decrease the level or effect of ferrous gluconate by increasing gastric pH. Applies only to oral form of both agents. Use Caution/Monitor.Minor (2)ferrous gluconate increases levels of calcium carbonate by enhancing GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown.
  
  calcium carbonate decreases levels of ferrous gluconate by inhibition of GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown.

• ferrous sulfate

  Minor (1)ferrous sulfate increases levels of calcium carbonate by enhancing GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown.

• flecainide

  Monitor Closely (1)calcium carbonate will increase the level or effect of flecainide by passive renal tubular reabsorption - basic urine. Use Caution/Monitor.

• fludrocortisone

  Minor (1)fludrocortisone decreases levels of calcium carbonate by increasing elimination. Minor/Significance Unknown.

• fosamprenavir

  Monitor Closely (1)calcium carbonate will decrease the level or effect of fosamprenavir by increasing gastric pH. Applies only to oral form of both agents. Use Caution/Monitor.

• fosinopril

  Monitor Closely (1)calcium carbonate decreases effects of fosinopril by unspecified interaction mechanism. Use Caution/Monitor.

• furosemide

  Minor (1)furosemide decreases levels of calcium carbonate by increasing renal clearance. Minor/Significance Unknown.

• gabapentin

  Monitor Closely (1)calcium carbonate decreases levels of gabapentin by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Separate by 2 hours.

• gabapentin enacarbil

  Monitor Closely (1)calcium carbonate decreases levels of gabapentin enacarbil by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Separate by 2 hours.

• gefitinib

  Monitor Closely (1)calcium carbonate decreases levels of gefitinib by increasing gastric pH. Applies only to oral form of both agents. Use Caution/Monitor. Separate gefitinib and antacid doses by at least 6 hr.

• gemifloxacin

  Monitor Closely (1)calcium carbonate, gemifloxacin. Either decreases levels of the other by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Separate by 2 hours.

• gentamicin

  Minor (1)gentamicin decreases levels of calcium carbonate by inhibition of GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown.

• glipizide

  Monitor Closely (1)calcium carbonate will increase the level or effect of glipizide by increasing gastric pH. Applies only to oral form of both agents. Use Caution/Monitor.

• glyburide

  Monitor Closely (1)calcium carbonate will increase the level or effect of glyburide by increasing gastric pH. Applies only to oral form of both agents. Use Caution/Monitor.

• hydrochlorothiazide

  Minor (1)hydrochlorothiazide increases levels of calcium carbonate by decreasing renal clearance. Minor/Significance Unknown. Risk of alkalosis, hypercalcemia.

• hydrocortisone

  Minor (1)hydrocortisone decreases levels of calcium carbonate by increasing elimination. Minor/Significance Unknown.

• ibandronate

  Monitor Closely (1)calcium carbonate decreases levels of ibandronate by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Separate by 30 minutes.

• imidapril

  Monitor Closely (1)calcium carbonate decreases effects of imidapril by unspecified interaction mechanism. Use Caution/Monitor.

• indapamide

  Minor (1)indapamide increases levels of calcium carbonate by decreasing renal clearance. Minor/Significance Unknown. Risk of alkalosis, hypercalcemia.

• indinavir

  Serious - Use Alternative (1)calcium carbonate will decrease the level or effect of indinavir by increasing gastric pH. Applies only to oral form of both agents. Avoid or Use Alternate Drug.

• infigratinib

  Serious - Use Alternative (1)calcium carbonate will decrease the level or effect of infigratinib by inhibition of GI absorption. Applies only to oral form of both agents. Avoid or Use Alternate Drug. If use with an acid-reducing agent cannot be avoided, administer infigratinib 2 hr before and after administration of a locally-acting antacid.

• iron dextran complex

  Monitor Closely (1)calcium carbonate will decrease the level or effect of iron dextran complex by increasing gastric pH. Applies only to oral form of both agents. Use Caution/Monitor.Minor (2)calcium carbonate decreases levels of iron dextran complex by inhibition of GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown.
  
  iron dextran complex increases levels of calcium carbonate by enhancing GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown.

• iron sucrose

  Monitor Closely (1)calcium carbonate will decrease the level or effect of iron sucrose by increasing gastric pH. Applies only to oral form of both agents. Use Caution/Monitor.Minor (2)calcium carbonate decreases levels of iron sucrose by inhibition of GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown.
  
  iron sucrose increases levels of calcium carbonate by enhancing GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown.

• isoniazid

  Monitor Closely (1)calcium carbonate decreases levels of isoniazid by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Separate by 2 hours.Minor (1)isoniazid decreases levels of calcium carbonate by inhibition of GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown.

• isotretinoin

  Minor (1)isotretinoin increases levels of calcium carbonate by enhancing GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown.

• isradipine

  Monitor Closely (1)calcium carbonate decreases effects of isradipine by pharmacodynamic antagonism. Use Caution/Monitor.

• itraconazole

  Monitor Closely (1)calcium carbonate will decrease the level or effect of itraconazole by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Administer acid neutralizing medicines at least 2 hours before or 2 hours after itraconazole.

• ketoconazole

  Monitor Closely (1)calcium carbonate decreases levels of ketoconazole by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Separate by 2 hours.Serious - Use Alternative (1)calcium carbonate will decrease the level or effect of ketoconazole by increasing gastric pH. Applies only to oral form of both agents. Avoid or Use Alternate Drug.

• labetalol

  Monitor Closely (2)calcium carbonate decreases effects of labetalol by unspecified interaction mechanism. Use Caution/Monitor.
  
  calcium carbonate decreases levels of labetalol by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Separate by 2 hours.

• lactulose

  Monitor Closely (1)calcium carbonate decreases effects of lactulose by pharmacodynamic antagonism. Use Caution/Monitor.

• lanthanum carbonate

  Monitor Closely (1)lanthanum carbonate, calcium carbonate. cation binding in GI tract. Use Caution/Monitor. Administer antacid at least 2 hours before or after lanthanum. .

• ledipasvir/sofosbuvir

  Monitor Closely (1)calcium carbonate decreases levels of ledipasvir/sofosbuvir by Other (see comment). Use Caution/Monitor. Comment: Ledipasvir solubility decreases as pH increases; drugs that increase gastric pH are expected to decrease levels of ledipasvir; separate antacid and ledipasivr/sofosbuvir administration by 4 hr.

• levofloxacin

  Monitor Closely (1)calcium carbonate, levofloxacin. Either decreases levels of the other by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Separate by 2 hours.

• levothyroxine

  Monitor Closely (1)calcium carbonate decreases levels of levothyroxine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Separate by 2 hours.

• lily of the valley

  Minor (1)calcium carbonate increases effects of lily of the valley by unspecified interaction mechanism. Minor/Significance Unknown.

• lisdexamfetamine

  Monitor Closely (1)calcium carbonate will increase the level or effect of lisdexamfetamine by passive renal tubular reabsorption - basic urine. Use Caution/Monitor.

• lisinopril

  Monitor Closely (1)calcium carbonate decreases effects of lisinopril by unspecified interaction mechanism. Use Caution/Monitor.

• manganese

  Minor (1)calcium carbonate, manganese. Either decreases levels of the other by inhibition of GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown. Separate by 2 hours.

• memantine

  Monitor Closely (1)calcium carbonate will increase the level or effect of memantine by passive renal tubular reabsorption - basic urine. Use Caution/Monitor.

• mesalamine

  Minor (1)calcium carbonate, mesalamine. Mechanism: passive renal tubular reabsorption due to increased pH. Minor/Significance Unknown. Salicylate levels increased at moderate doses; salicylate levels decreased at large doses (d/t increased renal excretion of unchanged salicylic acid).

• methscopolamine

  Monitor Closely (1)calcium carbonate decreases levels of methscopolamine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor.

• methyclothiazide

  Minor (1)methyclothiazide increases levels of calcium carbonate by decreasing renal clearance. Minor/Significance Unknown. Risk of alkalosis, hypercalcemia.

• methylphenidate

  Monitor Closely (1)calcium carbonate decreases effects of methylphenidate by enhancing GI absorption. Applies only to oral form of both agents. Modify Therapy/Monitor Closely. Since the characteristics of methylphenidate extended release capsules (Ritalin LA) are pH dependent, coadministration of antacids or acid suppressants could alter the release of methylphenidate. Consider separating the administration of the antacid and the methylphenidate extended-release capsules may be avoided.

• methylprednisolone

  Minor (1)methylprednisolone decreases levels of calcium carbonate by increasing elimination. Minor/Significance Unknown.

• metolazone

  Minor (1)metolazone increases levels of calcium carbonate by decreasing renal clearance. Minor/Significance Unknown. Risk of alkalosis, hypercalcemia.

• metoprolol

  Monitor Closely (2)calcium carbonate decreases effects of metoprolol by unspecified interaction mechanism. Use Caution/Monitor.
  
  calcium carbonate decreases levels of metoprolol by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Separate by 2 hours.

• mexiletine

  Monitor Closely (1)calcium carbonate will increase the level or effect of mexiletine by passive renal tubular reabsorption - basic urine. Use Caution/Monitor.

• minocycline

  Serious - Use Alternative (1)calcium carbonate, minocycline. Either decreases levels of the other by inhibition of GI absorption. Applies only to oral form of both agents. Avoid or Use Alternate Drug. Separate by 2 hours.

• moexipril

  Monitor Closely (1)calcium carbonate decreases effects of moexipril by unspecified interaction mechanism. Use Caution/Monitor.

• moxifloxacin

  Monitor Closely (1)calcium carbonate, moxifloxacin. Either decreases levels of the other by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Separate by 2 hours.

• mycophenolate

  Monitor Closely (1)calcium carbonate will decrease the level or effect of mycophenolate by increasing gastric pH. Applies only to oral form of both agents. Use Caution/Monitor.

• nadolol

  Monitor Closely (2)calcium carbonate decreases effects of nadolol by unspecified interaction mechanism. Use Caution/Monitor.
  
  calcium carbonate decreases levels of nadolol by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Separate by 2 hours.

• nebivolol

  Monitor Closely (2)calcium carbonate decreases effects of nebivolol by unspecified interaction mechanism. Use Caution/Monitor.
  
  calcium carbonate decreases levels of nebivolol by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Separate by 2 hours.

• neomycin PO

  Minor (1)neomycin PO decreases levels of calcium carbonate by inhibition of GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown.

• neratinib

  Monitor Closely (1)calcium carbonate will decrease the level or effect of neratinib by increasing gastric pH. Applies only to oral form of both agents. Modify Therapy/Monitor Closely. Separate antacid and neratinib dosing by 3 hr.

• nicardipine

  Monitor Closely (1)calcium carbonate decreases effects of nicardipine by pharmacodynamic antagonism. Use Caution/Monitor.

• nifedipine

  Monitor Closely (1)calcium carbonate decreases effects of nifedipine by pharmacodynamic antagonism. Use Caution/Monitor.

• nilotinib

  Monitor Closely (1)calcium carbonate decreases levels of nilotinib by increasing gastric pH. Applies only to oral form of both agents. Modify Therapy/Monitor Closely. Avoid this interaction by administering antacids 2 hr after or 2 hr before nilotinib.

• nimodipine

  Serious - Use Alternative (1)calcium carbonate will increase the level or effect of nimodipine by increasing gastric pH. Applies only to oral form of both agents. Avoid or Use Alternate Drug.

• nisoldipine

  Monitor Closely (1)calcium carbonate decreases effects of nisoldipine by pharmacodynamic antagonism. Use Caution/Monitor.Serious - Use Alternative (1)calcium carbonate will increase the level or effect of nisoldipine by increasing gastric pH. Applies only to oral form of both agents. Avoid or Use Alternate Drug.

• nitrendipine

  Serious - Use Alternative (1)calcium carbonate will increase the level or effect of nitrendipine by increasing gastric pH. Applies only to oral form of both agents. Avoid or Use Alternate Drug.

• nitrofurantoin

  Monitor Closely (1)calcium carbonate decreases levels of nitrofurantoin by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Separate by 2 hours.

• ofloxacin

  Monitor Closely (1)calcium carbonate, ofloxacin. Either decreases levels of the other by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Separate by 2 hours.

• omadacycline

  Monitor Closely (1)calcium carbonate will decrease the level or effect of omadacycline by inhibition of GI absorption. Applies only to oral form of both agents. Modify Therapy/Monitor Closely. Multivalent cation-containing products may impair absorption of tetracyclines, which may decrease its efficacy. Separate dosing of tetracyclines from these products.

• oxytetracycline

  Serious - Use Alternative (1)calcium carbonate, oxytetracycline. Either decreases levels of the other by inhibition of GI absorption. Applies only to oral form of both agents. Avoid or Use Alternate Drug. Separate by 2 hours.

• pamidronate

  Monitor Closely (1)calcium carbonate decreases levels of pamidronate by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Separate by 30 minutes.

• pancrelipase

  Monitor Closely (1)calcium carbonate decreases effects of pancrelipase by pharmacodynamic antagonism. Use Caution/Monitor. Antacids may negate beneficial effects of enzymes.

• paromomycin

  Minor (1)paromomycin decreases levels of calcium carbonate by inhibition of GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown.

• pazopanib

  Serious - Use Alternative (1)calcium carbonate will decrease the level or effect of pazopanib by increasing gastric pH. Applies only to oral form of both agents. Avoid or Use Alternate Drug. Avoid coadministration of pazopanib with drugs that raise gastric pH; may use short-acting antacids in place of PPIs and H2 antagonists, but separate antacid and pazopanib dosing by several hours

• penbutolol

  Monitor Closely (2)calcium carbonate decreases effects of penbutolol by unspecified interaction mechanism. Use Caution/Monitor.
  
  calcium carbonate decreases levels of penbutolol by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Separate by 2 hours.

• penicillamine

  Monitor Closely (1)calcium carbonate decreases levels of penicillamine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Separate by 2 hours.

• perindopril

  Monitor Closely (1)calcium carbonate decreases effects of perindopril by unspecified interaction mechanism. Use Caution/Monitor.

• pexidartinib

  Monitor Closely (1)calcium carbonate will decrease the level or effect of pexidartinib by inhibition of GI absorption. Applies only to oral form of both agents. Modify Therapy/Monitor Closely. Separate pexidartinib by 2 hr before or after taking a locally-acting antacid.

• pindolol

  Monitor Closely (2)calcium carbonate decreases effects of pindolol by unspecified interaction mechanism. Use Caution/Monitor.
  
  calcium carbonate decreases levels of pindolol by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Separate by 2 hours.

• polysaccharide iron

  Monitor Closely (1)calcium carbonate will decrease the level or effect of polysaccharide iron by increasing gastric pH. Applies only to oral form of both agents. Use Caution/Monitor.Minor (2)calcium carbonate decreases levels of polysaccharide iron by inhibition of GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown.
  
  polysaccharide iron increases levels of calcium carbonate by enhancing GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown.

• ponatinib

  Serious - Use Alternative (1)calcium carbonate decreases levels of ponatinib by increasing gastric pH. Applies only to oral form of both agents. Avoid or Use Alternate Drug.

• posaconazole

  Monitor Closely (1)calcium carbonate will decrease the level or effect of posaconazole by increasing gastric pH. Applies only to oral form of both agents. Use Caution/Monitor.

• potassium phosphates, IV

  Monitor Closely (1)calcium carbonate decreases effects of potassium phosphates, IV by cation binding in GI tract. Modify Therapy/Monitor Closely. Calcium decreases serum phosphate concentration by binding dietary phosphate. Use alternatives if available.

• prednisolone

  Minor (1)prednisolone decreases levels of calcium carbonate by increasing elimination. Minor/Significance Unknown.

• prednisone

  Minor (1)prednisone decreases levels of calcium carbonate by increasing elimination. Minor/Significance Unknown.

• propranolol

  Monitor Closely (2)calcium carbonate decreases effects of propranolol by unspecified interaction mechanism. Use Caution/Monitor.
  
  calcium carbonate decreases levels of propranolol by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Separate by 2 hours.

• quinapril

  Monitor Closely (1)calcium carbonate decreases effects of quinapril by unspecified interaction mechanism. Use Caution/Monitor.

• quinidine

  Monitor Closely (1)calcium carbonate will increase the level or effect of quinidine by passive renal tubular reabsorption - basic urine. Use Caution/Monitor. Elevated quinidine plasma levels, possibly with cardiac conduction disturbances and arrhythmias, may occur.

• ramipril

  Monitor Closely (1)calcium carbonate decreases effects of ramipril by unspecified interaction mechanism. Use Caution/Monitor.

• rifampin

  Monitor Closely (1)calcium carbonate will decrease the level or effect of rifampin by Other (see comment). Use Caution/Monitor. Concomitant antacid administration may reduce absorption of rifampin; daily doses of rifampin should be given at least 1 hr before ingestion of antacids

• rilpivirine

  Monitor Closely (1)calcium carbonate decreases levels of rilpivirine by increasing gastric pH. Applies only to oral form of both agents. Modify Therapy/Monitor Closely. Coadministration of antacids with rilpivirine may cause significant decreases in rilpivirine plasma concentrations because of increased gastric pH. If antacids must be administered, they should be given at least 2 hr before or at least 4 hr after rilpivirine. For the combination product dolutegravir/rilpivirine, antacids should be given at least 4 hr before or at least 6 hr afterwards.

• riociguat

  Monitor Closely (1)calcium carbonate decreases levels of riociguat by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Separate administration by at least 1 hour.

• risedronate

  Monitor Closely (1)calcium carbonate decreases levels of risedronate by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Separate by 30 minutes.

• rose hips

  Monitor Closely (1)calcium carbonate will decrease the level or effect of rose hips by increasing gastric pH. Applies only to oral form of both agents. Use Caution/Monitor.Minor (2)calcium carbonate decreases levels of rose hips by inhibition of GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown.
  
  rose hips increases levels of calcium carbonate by enhancing GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown.

• rosuvastatin

  Monitor Closely (1)calcium carbonate decreases levels of rosuvastatin by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Separate by 2 hours.

• salicylates (non-asa)

  Minor (1)calcium carbonate, salicylates (non-asa). Mechanism: passive renal tubular reabsorption due to increased pH. Minor/Significance Unknown. Salicylate levels increased at moderate doses; salicylate levels decreased at large doses (d/t increased renal excretion of unchanged salicylic acid).

• salsalate

  Minor (1)calcium carbonate, salsalate. Mechanism: passive renal tubular reabsorption due to increased pH. Minor/Significance Unknown. Salicylate levels increased at moderate doses; salicylate levels decreased at large doses (d/t increased renal excretion of unchanged salicylic acid).

• sarecycline

  Monitor Closely (1)calcium carbonate will decrease the level or effect of sarecycline by inhibition of GI absorption. Applies only to oral form of both agents. Modify Therapy/Monitor Closely. Multivalent cation-containing products may impair absorption of tetracyclines, which may decrease its efficacy. Separate dosing of tetracyclines from these products.

• shark cartilage

  Minor (1)calcium carbonate, shark cartilage. pharmacodynamic synergism. Minor/Significance Unknown. May lead to hypercalcemia (theoretical).

• sodium phosphates, IV

  Monitor Closely (1)calcium carbonate decreases effects of sodium phosphates, IV by cation binding in GI tract. Modify Therapy/Monitor Closely. Calcium decreases serum phosphate concentration by binding dietary phosphate. Use alternatives if available.

• sodium polystyrene sulfonate

  Minor (1)sodium polystyrene sulfonate increases levels of calcium carbonate by decreasing renal clearance. Minor/Significance Unknown. Risk of alkalosis.

• sodium sulfate/?magnesium sulfate/potassium chloride

  Monitor Closely (1)sodium sulfate/?magnesium sulfate/potassium chloride increases toxicity of calcium carbonate by Other (see comment). Use Caution/Monitor. Comment: Coadministration with medications that cause fluid and electrolyte abnormalities may increase the risk of adverse events of seizure, arrhythmias, and renal impairment.

• sodium sulfate/potassium sulfate/magnesium sulfate

  Monitor Closely (1)sodium sulfate/potassium sulfate/magnesium sulfate increases toxicity of calcium carbonate by Other (see comment). Use Caution/Monitor. Comment: Coadministration with medications that cause fluid and electrolyte abnormalities may increase the risk of adverse events of seizure, arrhythmias, and renal impairment.

• sofosbuvir/velpatasvir

  Monitor Closely (1)calcium carbonate will decrease the level or effect of sofosbuvir/velpatasvir by increasing gastric pH. Applies only to oral form of both agents. Modify Therapy/Monitor Closely. Velpatasvir solubility decreases as gastric pH increases (practically insoluble at pH >5). Separate administration of sofosbuvir/velpatasvir from antacids by at least 4 hr.

• sotalol

  Monitor Closely (2)calcium carbonate decreases effects of sotalol by unspecified interaction mechanism. Use Caution/Monitor.
  
  calcium carbonate decreases levels of sotalol by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Separate by 2 hours.

• sotorasib

  Serious - Use Alternative (1)calcium carbonate will decrease the level or effect of sotorasib by inhibition of GI absorption. Applies only to oral form of both agents. Avoid or Use Alternate Drug. If use with an acid-reducing agent cannot be avoided, administer sotorasib 4 hr before or 10 hr after administration of a locally-acting antacid.

• spironolactone

  Minor (1)spironolactone decreases levels of calcium carbonate by increasing renal clearance. Minor/Significance Unknown.

• squill

  Monitor Closely (1)calcium carbonate increases toxicity of squill by unspecified interaction mechanism. Use Caution/Monitor.

• streptomycin

  Minor (1)streptomycin decreases levels of calcium carbonate by inhibition of GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown.

• strontium ranelate

  Monitor Closely (1)calcium carbonate decreases levels of strontium ranelate by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Applies to oral form of calcium. Separate by 2 hr.

• sulfasalazine

  Minor (1)calcium carbonate, sulfasalazine. Mechanism: passive renal tubular reabsorption due to increased pH. Minor/Significance Unknown. Salicylate levels increased at moderate doses; salicylate levels decreased at large doses (d/t increased renal excretion of unchanged salicylic acid).

• teriparatide

  Minor (1)teriparatide increases levels of calcium carbonate by pharmacodynamic synergism. Minor/Significance Unknown.

• tetracycline

  Serious - Use Alternative (1)calcium carbonate, tetracycline. Either decreases levels of the other by inhibition of GI absorption. Applies only to oral form of both agents. Avoid or Use Alternate Drug. Separate by 2 hours.

• tiludronate

  Monitor Closely (1)calcium carbonate decreases levels of tiludronate by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Separate by 30 minutes.

• timolol

  Monitor Closely (2)calcium carbonate decreases effects of timolol by unspecified interaction mechanism. Use Caution/Monitor.
  
  calcium carbonate decreases levels of timolol by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Separate by 2 hours.

• tobramycin

  Minor (1)tobramycin decreases levels of calcium carbonate by inhibition of GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown.

• tolbutamide

  Monitor Closely (1)calcium carbonate will increase the level or effect of tolbutamide by increasing gastric pH. Applies only to oral form of both agents. Use Caution/Monitor.

• torsemide

  Minor (1)torsemide decreases levels of calcium carbonate by increasing renal clearance. Minor/Significance Unknown.

• trandolapril

  Monitor Closely (1)calcium carbonate decreases effects of trandolapril by unspecified interaction mechanism. Use Caution/Monitor.

• triamcinolone acetonide injectable suspension

  Minor (1)triamcinolone acetonide injectable suspension decreases levels of calcium carbonate by increasing elimination. Minor/Significance Unknown.

• triamterene

  Minor (1)triamterene decreases levels of calcium carbonate by increasing renal clearance. Minor/Significance Unknown.

• ursodiol

  Monitor Closely (1)calcium carbonate decreases effects of ursodiol by pharmacodynamic antagonism. Use Caution/Monitor.

• verapamil

  Monitor Closely (1)calcium carbonate decreases effects of verapamil by pharmacodynamic antagonism. Use Caution/Monitor.

• vismodegib

  Monitor Closely (1)calcium carbonate will decrease the level or effect of vismodegib by Other (see comment). Use Caution/Monitor. Drugs that increase gastric pH alter vismodegib solubility and therefore reduce bioavailability; effect on efficacy unknown

• vitamin D

  Monitor Closely (1)vitamin D, calcium carbonate. Other (see comment). Use Caution/Monitor. Comment: The concurrent use of vitamin D with calcium salts is generally beneficial; in some patients this combination may result in hypercalcemia.

• willow bark

  Minor (1)calcium carbonate, willow bark. Mechanism: passive renal tubular reabsorption due to increased pH. Minor/Significance Unknown. Salicylate levels increased at moderate doses; salicylate levels decreased at large doses (d/t increased renal excretion of unchanged salicylic acid).

• zoledronic acid

  Monitor Closely (1)calcium carbonate decreases levels of zoledronic acid by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Separate by 30 minutes.