Dosing & Uses
Dosage Forms & Strengths
capsule
- 250mg
Acute Pain
Initial 500 mg PO once, THEN
250 mg PO q6hr PRN usually not to exceed 7 days
Primary Dysmenorrhea
Initial 500 mg PO once, THEN
250 mg PO q6hr PRN usually not to exceed 3 days
Administration
Take with food or 8-12 oz water to avoid GI effects
For dysmenorrhea, start with onset of bleeding & pain
Other Indications & Uses
Off-label: Vascular headache
Dosage Forms & Strengths
capsule
- 250mg
Acute Pain
<14 years old: Not recommended
≥14 years old: Initial 500 mg PO once, THEN
250 mg PO q6hr PRN usually not to exceed 7 days
Primary Dysmenorrhea
<14 years old: Not recommended
≥14 years old: Initial 500 mg PO once, THEN
250 mg PO q6hr PRN usually not to exceed 3 days
Acute pain
Initial 500 mg PO once, THEN
250 mg PO q6hr PRN usually not to exceed 7 days
Interactions
Interaction Checker
No Results
Contraindicated
Serious - Use Alternative
Significant - Monitor Closely
Minor
Contraindicated (0)
Serious - Use Alternative (22)
- aminolevulinic acid oral
aminolevulinic acid oral, mefenamic acid. Either increases toxicity of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Avoid administering other phototoxic drugs with aminolevulinic acid oral for 24 hr during perioperative period.
- aminolevulinic acid topical
mefenamic acid, aminolevulinic acid topical. Either increases toxicity of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Each drug may increase the photosensitizing effect of the other.
- apixaban
mefenamic acid and apixaban both increase anticoagulation. Avoid or Use Alternate Drug.
- baricitinib
mefenamic acid will increase the level or effect of baricitinib by decreasing elimination. Avoid or Use Alternate Drug. Coadministration of baricitinib with strong organic anion transporter 3 (OAT3) inhibitors is not recommended.
- benazepril
mefenamic acid, benazepril. pharmacodynamic antagonism. Avoid or Use Alternate Drug. Coadministration may result in a significant decrease in renal function. NSAIDs may diminish the antihypertensive effect of ACE inhibitors. The mechanism of these interactions is likely related to the ability of NSAIDs to reduce the synthesis of vasodilating renal prostaglandins.
- captopril
mefenamic acid, captopril. pharmacodynamic antagonism. Avoid or Use Alternate Drug. Coadministration may result in a significant decrease in renal function. NSAIDs may diminish the antihypertensive effect of ACE inhibitors. The mechanism of these interactions is likely related to the ability of NSAIDs to reduce the synthesis of vasodilating renal prostaglandins.
- enalapril
mefenamic acid, enalapril. pharmacodynamic antagonism. Avoid or Use Alternate Drug. Coadministration may result in a significant decrease in renal function. NSAIDs may diminish the antihypertensive effect of ACE inhibitors. The mechanism of these interactions is likely related to the ability of NSAIDs to reduce the synthesis of vasodilating renal prostaglandins.
- erdafitinib
mefenamic acid will increase the level or effect of erdafitinib by affecting hepatic enzyme CYP2C9/10 metabolism. Avoid or Use Alternate Drug. If unable to avoid coadministration with strong CYP2C9 inhibitors, monitor closely for adverse reactions and consider decreasing dose accordingly. If strong CYP2C9 inhibitor is discontinued, consider increasing erdafitinib dose in the absence of any drug-related toxicities.
- fosinopril
mefenamic acid, fosinopril. pharmacodynamic antagonism. Avoid or Use Alternate Drug. Coadministration may result in a significant decrease in renal function. NSAIDs may diminish the antihypertensive effect of ACE inhibitors. The mechanism of these interactions is likely related to the ability of NSAIDs to reduce the synthesis of vasodilating renal prostaglandins.
- ketorolac
mefenamic acid, ketorolac. Either increases toxicity of the other by pharmacodynamic synergism. Contraindicated.
- ketorolac intranasal
mefenamic acid, ketorolac intranasal. Either increases toxicity of the other by pharmacodynamic synergism. Contraindicated.
- lisinopril
mefenamic acid, lisinopril. pharmacodynamic antagonism. Avoid or Use Alternate Drug. Coadministration may result in a significant decrease in renal function. NSAIDs may diminish the antihypertensive effect of ACE inhibitors. The mechanism of these interactions is likely related to the ability of NSAIDs to reduce the synthesis of vasodilating renal prostaglandins.
- methotrexate
mefenamic acid increases levels of methotrexate by decreasing renal clearance. Avoid or Use Alternate Drug. Concomitant administration of NSAIDs with high dose methotrexate has been reported to elevate and prolong serum methotrexate levels, resulting in deaths from severe hematologic and GI toxicity. NSAIDs may reduce tubular secretion of methotrexate and enhance toxicity. .
- methyl aminolevulinate
mefenamic acid, methyl aminolevulinate. Either increases toxicity of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Each drug may increase the photosensitizing effect of the other.
- moexipril
mefenamic acid, moexipril. pharmacodynamic antagonism. Avoid or Use Alternate Drug. Coadministration may result in a significant decrease in renal function. NSAIDs may diminish the antihypertensive effect of ACE inhibitors. The mechanism of these interactions is likely related to the ability of NSAIDs to reduce the synthesis of vasodilating renal prostaglandins.
- pemetrexed
mefenamic acid increases levels of pemetrexed by unspecified interaction mechanism. Avoid or Use Alternate Drug. Interrupt dosing in all patients taking NSAIDs with long elimination half-lives for at least 5d before, the day of, and 2d following pemetrexed administration. If coadministration of an NSAID is necessary, closely monitor patients for toxicity, especially myelosuppression, renal toxicity, and GI toxicity.
- perindopril
mefenamic acid, perindopril. pharmacodynamic antagonism. Avoid or Use Alternate Drug. Coadministration may result in a significant decrease in renal function. NSAIDs may diminish the antihypertensive effect of ACE inhibitors. The mechanism of these interactions is likely related to the ability of NSAIDs to reduce the synthesis of vasodilating renal prostaglandins.
- quinapril
mefenamic acid, quinapril. pharmacodynamic antagonism. Avoid or Use Alternate Drug. Coadministration may result in a significant decrease in renal function. NSAIDs may diminish the antihypertensive effect of ACE inhibitors. The mechanism of these interactions is likely related to the ability of NSAIDs to reduce the synthesis of vasodilating renal prostaglandins.
- ramipril
mefenamic acid, ramipril. pharmacodynamic antagonism. Avoid or Use Alternate Drug. Coadministration may result in a significant decrease in renal function. NSAIDs may diminish the antihypertensive effect of ACE inhibitors. The mechanism of these interactions is likely related to the ability of NSAIDs to reduce the synthesis of vasodilating renal prostaglandins.
- siponimod
mefenamic acid will increase the level or effect of siponimod by affecting hepatic enzyme CYP2C9/10 metabolism. Avoid or Use Alternate Drug. Coadministration of siponimod with drugs that cause moderate CYP2C9 AND a moderate or strong CYP3A4 inhibition is not recommended. Caution if siponimod coadministered with moderate CYP2C9 inhibitors alone.
- tacrolimus
mefenamic acid, tacrolimus. Either increases toxicity of the other by Other (see comment). Avoid or Use Alternate Drug. Comment: Concomitant administration increases risk of nephrotoxicity.
- trandolapril
mefenamic acid, trandolapril. pharmacodynamic antagonism. Avoid or Use Alternate Drug. Coadministration may result in a significant decrease in renal function. NSAIDs may diminish the antihypertensive effect of ACE inhibitors. The mechanism of these interactions is likely related to the ability of NSAIDs to reduce the synthesis of vasodilating renal prostaglandins.
Monitor Closely (241)
- acebutolol
acebutolol and mefenamic acid both increase serum potassium. Use Caution/Monitor.
mefenamic acid decreases effects of acebutolol by pharmacodynamic antagonism. Use Caution/Monitor. Long term (>1 wk) NSAID use. NSAIDs decrease prostaglandin synthesis. - aceclofenac
aceclofenac and mefenamic acid both increase anticoagulation. Use Caution/Monitor.
aceclofenac and mefenamic acid both increase serum potassium. Use Caution/Monitor. - acemetacin
acemetacin and mefenamic acid both increase anticoagulation. Use Caution/Monitor.
acemetacin and mefenamic acid both increase serum potassium. Use Caution/Monitor. - agrimony
mefenamic acid and agrimony both increase anticoagulation. Use Caution/Monitor.
- albuterol
mefenamic acid increases and albuterol decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- alfalfa
mefenamic acid and alfalfa both increase anticoagulation. Use Caution/Monitor.
- alfuzosin
mefenamic acid decreases effects of alfuzosin by pharmacodynamic antagonism. Use Caution/Monitor. NSAIDs decrease prostaglandin synthesis.
- aliskiren
mefenamic acid will decrease the level or effect of aliskiren by Other (see comment). Use Caution/Monitor. In patients who are elderly, volume-depleted (including those on diuretic therapy), or with compromised renal function, coadministration of NSAIDs with drugs that affect RAAS may increase the risk of renal impairment (including acute renal failure) and cause loss of antihypertensive effect. Monitor renal function periodically.
- alteplase
mefenamic acid and alteplase both increase anticoagulation. Use Caution/Monitor. Potential for increased risk of bleeding, caution is advised.
- American ginseng
mefenamic acid and American ginseng both increase anticoagulation. Use Caution/Monitor.
- amiloride
amiloride and mefenamic acid both increase serum potassium. Modify Therapy/Monitor Closely.
- antithrombin alfa
antithrombin alfa and mefenamic acid both increase anticoagulation. Modify Therapy/Monitor Closely.
- antithrombin III
antithrombin III and mefenamic acid both increase anticoagulation. Modify Therapy/Monitor Closely.
- arformoterol
mefenamic acid increases and arformoterol decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- argatroban
argatroban and mefenamic acid both increase anticoagulation. Modify Therapy/Monitor Closely.
- asenapine
mefenamic acid decreases effects of asenapine by pharmacodynamic antagonism. Use Caution/Monitor. NSAIDs decrease prostaglandin synthesis.
- aspirin
aspirin and mefenamic acid both increase anticoagulation. Use Caution/Monitor.
aspirin and mefenamic acid both increase serum potassium. Use Caution/Monitor. - aspirin rectal
aspirin rectal and mefenamic acid both increase anticoagulation. Use Caution/Monitor.
aspirin rectal and mefenamic acid both increase serum potassium. Use Caution/Monitor. - aspirin/citric acid/sodium bicarbonate
aspirin/citric acid/sodium bicarbonate and mefenamic acid both increase anticoagulation. Use Caution/Monitor.
aspirin/citric acid/sodium bicarbonate and mefenamic acid both increase serum potassium. Use Caution/Monitor. - atenolol
atenolol and mefenamic acid both increase serum potassium. Use Caution/Monitor.
mefenamic acid decreases effects of atenolol by pharmacodynamic antagonism. Use Caution/Monitor. Long term (>1 wk) NSAID use. NSAIDs decrease prostaglandin synthesis. - azficel-T
azficel-T, mefenamic acid. Other (see comment). Use Caution/Monitor. Comment: Patients taking NSAIDS may experience increased bruising or bleeding at biopsy and/or injection sites. Concomitant use of NSAIDs is not recommended.
- azilsartan
mefenamic acid, azilsartan. Either increases toxicity of the other by Other (see comment). Use Caution/Monitor. Comment: May result in renal function deterioration, particularly in elderly or volume depleted individuals.
mefenamic acid decreases effects of azilsartan by pharmacodynamic antagonism. Modify Therapy/Monitor Closely. NSAIDs decrease synthesis of vasodilating renal prostaglandins, and thus affect fluid homeostasis and may diminish antihypertensive effect. - bemiparin
bemiparin and mefenamic acid both increase anticoagulation. Modify Therapy/Monitor Closely.
- benazepril
benazepril, mefenamic acid. Either increases toxicity of the other by Other (see comment). Use Caution/Monitor. Comment: May result in renal function deterioration, particularly in elderly or volume depleted individuals.
- bendroflumethiazide
mefenamic acid increases and bendroflumethiazide decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- betaxolol
betaxolol and mefenamic acid both increase serum potassium. Use Caution/Monitor.
mefenamic acid decreases effects of betaxolol by pharmacodynamic antagonism. Use Caution/Monitor. Long term (>1 wk) NSAID use. NSAIDs decrease prostaglandin synthesis. - betrixaban
mefenamic acid, betrixaban. Either increases levels of the other by anticoagulation. Use Caution/Monitor.
- bimatoprost
bimatoprost, mefenamic acid. unspecified interaction mechanism. Use Caution/Monitor. There are conflicting reports from studies of either increased or decreased IOP when ophthalmic prostaglandins are coadministered with NSAIDs (either systemic or ophthalmic).
- bisoprolol
bisoprolol and mefenamic acid both increase serum potassium. Use Caution/Monitor.
mefenamic acid decreases effects of bisoprolol by pharmacodynamic antagonism. Use Caution/Monitor. Long term (>1 wk) NSAID use. NSAIDs decrease prostaglandin synthesis. - bivalirudin
bivalirudin and mefenamic acid both increase anticoagulation. Modify Therapy/Monitor Closely.
- budesonide
mefenamic acid, budesonide. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of GI ulceration.
- bumetanide
mefenamic acid increases and bumetanide decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
mefenamic acid decreases effects of bumetanide by pharmacodynamic antagonism. Use Caution/Monitor. NSAIDs decrease prostaglandin synthesis. - candesartan
candesartan and mefenamic acid both increase serum potassium. Use Caution/Monitor.
mefenamic acid decreases effects of candesartan by pharmacodynamic antagonism. Modify Therapy/Monitor Closely. NSAIDs decrease synthesis of vasodilating renal prostaglandins, and thus affect fluid homeostasis and may diminish antihypertensive effect.
candesartan, mefenamic acid. Either increases toxicity of the other by Other (see comment). Use Caution/Monitor. Comment: May result in renal function deterioration, particularly in elderly or volume depleted individuals. - captopril
captopril, mefenamic acid. Either increases toxicity of the other by Other (see comment). Use Caution/Monitor. Comment: May result in renal function deterioration, particularly in elderly or volume depleted individuals.
- carbenoxolone
mefenamic acid increases and carbenoxolone decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- carvedilol
carvedilol and mefenamic acid both increase serum potassium. Use Caution/Monitor.
mefenamic acid decreases effects of carvedilol by pharmacodynamic antagonism. Use Caution/Monitor. Long term (>1 wk) NSAID use. NSAIDs decrease prostaglandin synthesis. - celecoxib
celecoxib and mefenamic acid both increase anticoagulation. Use Caution/Monitor.
celecoxib and mefenamic acid both increase serum potassium. Use Caution/Monitor. - celiprolol
celiprolol and mefenamic acid both increase serum potassium. Use Caution/Monitor.
mefenamic acid decreases effects of celiprolol by pharmacodynamic antagonism. Use Caution/Monitor. Long term (>1 wk) NSAID use. NSAIDs decrease prostaglandin synthesis. - chlorothiazide
mefenamic acid increases and chlorothiazide decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- chlorpropamide
mefenamic acid increases effects of chlorpropamide by unknown mechanism. Use Caution/Monitor. Risk of hypoglycemia.
- chlorthalidone
mefenamic acid increases and chlorthalidone decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- choline magnesium trisalicylate
mefenamic acid and choline magnesium trisalicylate both increase anticoagulation. Use Caution/Monitor.
mefenamic acid and choline magnesium trisalicylate both increase serum potassium. Use Caution/Monitor. - cinnamon
mefenamic acid and cinnamon both increase anticoagulation. Use Caution/Monitor.
- ciprofloxacin
mefenamic acid, ciprofloxacin. Other (see comment). Modify Therapy/Monitor Closely. Comment: Mechanism: unknown. Increased risk of CNS stimulation and seizures with high doses of fluoroquinolones.
- citalopram
citalopram, mefenamic acid. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of upper GI bleeding. If possible, avoid concurrent use.
- clomipramine
clomipramine, mefenamic acid. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of upper GI bleeding. Clomipramine inhib. serotonin uptake by platelets.
- clopidogrel
clopidogrel, mefenamic acid. Either increases effects of the other by pharmacodynamic synergism. Modify Therapy/Monitor Closely. Clopidogrel and NSAIDs both inhibit platelet aggregation.
- cordyceps
mefenamic acid and cordyceps both increase anticoagulation. Use Caution/Monitor.
- cortisone
mefenamic acid, cortisone. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of GI ulceration.
- cyclopenthiazide
mefenamic acid increases and cyclopenthiazide decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- cyclosporine
mefenamic acid, cyclosporine. Either increases toxicity of the other by nephrotoxicity and/or ototoxicity. Modify Therapy/Monitor Closely.
- dabigatran
dabigatran and mefenamic acid both increase anticoagulation. Use Caution/Monitor. Caution is advised, both drugs have the potential to cause bleeding. Concomitant use may increase risk of bleeding.
- dalteparin
dalteparin and mefenamic acid both increase anticoagulation. Modify Therapy/Monitor Closely.
- deferasirox
deferasirox, mefenamic acid. Other (see comment). Use Caution/Monitor. Comment: Combination may increase GI bleeding, ulceration and irritation. Use with caution.
- defibrotide
defibrotide increases effects of mefenamic acid by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor. Defibrotide may enhance effects of platelet inhibitors.
- deflazacort
mefenamic acid, deflazacort. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of GI ulceration.
- dexamethasone
mefenamic acid, dexamethasone. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of GI ulceration.
- diclofenac
diclofenac and mefenamic acid both increase anticoagulation. Use Caution/Monitor.
diclofenac and mefenamic acid both increase serum potassium. Use Caution/Monitor. - diflunisal
diflunisal and mefenamic acid both increase anticoagulation. Use Caution/Monitor.
diflunisal and mefenamic acid both increase serum potassium. Use Caution/Monitor. - digoxin
mefenamic acid and digoxin both increase serum potassium. Use Caution/Monitor.
- dobutamine
mefenamic acid increases and dobutamine decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- dong quai
mefenamic acid and dong quai both increase anticoagulation. Use Caution/Monitor.
- dopexamine
mefenamic acid increases and dopexamine decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- doxazosin
mefenamic acid decreases effects of doxazosin by pharmacodynamic antagonism. Use Caution/Monitor. NSAIDs decrease prostaglandin synthesis.
- dronabinol
mefenamic acid will increase the level or effect of dronabinol by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor. Dronabinol is a CYP2C9 substrate.
- drospirenone
drospirenone and mefenamic acid both increase serum potassium. Modify Therapy/Monitor Closely.
- duloxetine
duloxetine, mefenamic acid. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of upper GI bleeding. SSRIs inhib. serotonin uptake by platelets.
- edoxaban
edoxaban, mefenamic acid. Either increases toxicity of the other by anticoagulation. Modify Therapy/Monitor Closely. Both drugs have the potential to cause bleeding, monitor closely. Promptly evaluate any signs or symptoms of blood loss.
- eltrombopag
eltrombopag increases levels of mefenamic acid by decreasing metabolism. Use Caution/Monitor. UGT inhibition; significance of interaction unclear.
- eluxadoline
mefenamic acid increases levels of eluxadoline by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor. As a precautionary measure due to incomplete information on the metabolism of eluxadoline, use caution when coadministered with strong CYP2C9/10 inhibitors.
- elvitegravir/cobicistat/emtricitabine/tenofovir DF
elvitegravir/cobicistat/emtricitabine/tenofovir DF, mefenamic acid. Either increases toxicity of the other by decreasing renal clearance. Modify Therapy/Monitor Closely. Toxicity may result from coadministration of emtricitabine and tenofovir with other drugs that are also primarily excreted by glomerular filtration and/or active tubular secretion including high-dose or multiple-dose NSAIDs; alternatives to NSAIDs should be considered.
- emtricitabine
emtricitabine, mefenamic acid. Either increases levels of the other by decreasing renal clearance. Modify Therapy/Monitor Closely. Toxicity may result from coadministration of emtricitabine with other drugs that are also primarily excreted by glomerular filtration and/or active tubular secretion including high-dose or multiple-dose NSAIDs; alternatives to NSAIDs should be considered.
- enalapril
enalapril, mefenamic acid. Either increases toxicity of the other by Other (see comment). Use Caution/Monitor. Comment: May result in renal function deterioration, particularly in elderly or volume depleted individuals.
- enoxaparin
enoxaparin and mefenamic acid both increase anticoagulation. Modify Therapy/Monitor Closely.
- ephedrine
mefenamic acid increases and ephedrine decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- epinephrine
mefenamic acid increases and epinephrine decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- epinephrine racemic
mefenamic acid increases and epinephrine racemic decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- epoprostenol
mefenamic acid and epoprostenol both increase anticoagulation. Use Caution/Monitor.
- eprosartan
eprosartan and mefenamic acid both increase serum potassium. Use Caution/Monitor.
mefenamic acid decreases effects of eprosartan by pharmacodynamic antagonism. Modify Therapy/Monitor Closely. NSAIDs decrease synthesis of vasodilating renal prostaglandins, and thus affect fluid homeostasis and may diminish antihypertensive effect.
eprosartan, mefenamic acid. Either increases toxicity of the other by Other (see comment). Use Caution/Monitor. Comment: May result in renal function deterioration, particularly in elderly or volume depleted individuals. - escitalopram
escitalopram, mefenamic acid. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of upper GI bleeding. SSRIs inhib. serotonin uptake by platelets.
- esmolol
esmolol and mefenamic acid both increase serum potassium. Use Caution/Monitor.
mefenamic acid decreases effects of esmolol by pharmacodynamic antagonism. Use Caution/Monitor. Long term (>1 wk) NSAID use. NSAIDs decrease prostaglandin synthesis. - ethacrynic acid
mefenamic acid increases and ethacrynic acid decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- etodolac
etodolac and mefenamic acid both increase anticoagulation. Use Caution/Monitor.
etodolac and mefenamic acid both increase serum potassium. Use Caution/Monitor. - fennel
mefenamic acid and fennel both increase anticoagulation. Use Caution/Monitor.
- fenoprofen
fenoprofen and mefenamic acid both increase anticoagulation. Use Caution/Monitor.
fenoprofen and mefenamic acid both increase serum potassium. Use Caution/Monitor. - feverfew
mefenamic acid and feverfew both increase anticoagulation. Use Caution/Monitor.
- fish oil triglycerides
fish oil triglycerides will increase the level or effect of mefenamic acid by anticoagulation. Use Caution/Monitor. Prolonged bleeding reported in patients taking antiplatelet agents or anticoagulants and oral omega-3 fatty acids. Periodically monitor bleeding time in patients receiving fish oil triglycerides and concomitant antiplatelet agents or anticoagulants.
- fludrocortisone
mefenamic acid, fludrocortisone. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of GI ulceration.
- fluoxetine
fluoxetine, mefenamic acid. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of upper GI bleeding. SSRIs inhib. serotonin uptake by platelets.
- flurbiprofen
flurbiprofen and mefenamic acid both increase anticoagulation. Use Caution/Monitor.
flurbiprofen and mefenamic acid both increase serum potassium. Use Caution/Monitor. - fluvoxamine
fluvoxamine, mefenamic acid. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of upper GI bleeding SSRIs inhib. serotonin uptake by platelets.
- fondaparinux
fondaparinux and mefenamic acid both increase anticoagulation. Modify Therapy/Monitor Closely.
- formoterol
mefenamic acid increases and formoterol decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- forskolin
mefenamic acid and forskolin both increase anticoagulation. Use Caution/Monitor.
- fosinopril
fosinopril, mefenamic acid. Either increases toxicity of the other by Other (see comment). Use Caution/Monitor. Comment: May result in renal function deterioration, particularly in elderly or volume depleted individuals.
- furosemide
mefenamic acid increases and furosemide decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- garlic
mefenamic acid and garlic both increase anticoagulation. Use Caution/Monitor.
- gemifloxacin
gemifloxacin, mefenamic acid. Other (see comment). Modify Therapy/Monitor Closely. Comment: Increased risk of CNS stimulation and seizures with high doses of fluoroquinolones.
- gentamicin
mefenamic acid increases and gentamicin decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- ginger
mefenamic acid and ginger both increase anticoagulation. Use Caution/Monitor.
- ginkgo biloba
mefenamic acid and ginkgo biloba both increase anticoagulation. Use Caution/Monitor.
- glimepiride
mefenamic acid increases effects of glimepiride by unknown mechanism. Use Caution/Monitor. Risk of hypoglycemia.
- glipizide
mefenamic acid increases effects of glipizide by unknown mechanism. Use Caution/Monitor. Risk of hypoglycemia.
- glyburide
mefenamic acid increases effects of glyburide by unknown mechanism. Use Caution/Monitor. Risk of hypoglycemia.
mefenamic acid increases levels of glyburide by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor. Strong CYP2C9 inhibitors may decrease glyburide metabolism. - green tea
green tea, mefenamic acid. Other (see comment). Use Caution/Monitor. Comment: Combination may increase risk of bleeding.
- heparin
heparin and mefenamic acid both increase anticoagulation. Modify Therapy/Monitor Closely.
- horse chestnut seed
mefenamic acid and horse chestnut seed both increase anticoagulation. Use Caution/Monitor.
- hydralazine
mefenamic acid decreases effects of hydralazine by pharmacodynamic antagonism. Use Caution/Monitor. NSAIDs decrease prostaglandin synthesis.
- hydrochlorothiazide
mefenamic acid increases and hydrochlorothiazide decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- hydrocortisone
mefenamic acid, hydrocortisone. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of GI ulceration.
- ibrutinib
ibrutinib will increase the level or effect of mefenamic acid by anticoagulation. Use Caution/Monitor. Ibrutinib may increase the risk of hemorrhage in patients receiving antiplatelet or anticoagulant therapies and monitor for signs of bleeding.
- ibuprofen
ibuprofen and mefenamic acid both increase anticoagulation. Use Caution/Monitor.
ibuprofen and mefenamic acid both increase serum potassium. Use Caution/Monitor. - ibuprofen IV
ibuprofen IV and mefenamic acid both increase anticoagulation. Use Caution/Monitor.
ibuprofen IV and mefenamic acid both increase serum potassium. Use Caution/Monitor. - imatinib
imatinib, mefenamic acid. Either increases toxicity of the other by Other (see comment). Modify Therapy/Monitor Closely. Comment: Imatinib may cause thrombocytopenia; bleeding risk increased when imatinib is coadministered with anticoagulants, NSAIDs, platelet inhibitors, and thrombolytic agents.
- indapamide
mefenamic acid increases and indapamide decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- indomethacin
indomethacin and mefenamic acid both increase anticoagulation. Use Caution/Monitor.
indomethacin and mefenamic acid both increase serum potassium. Use Caution/Monitor. - irbesartan
irbesartan and mefenamic acid both increase serum potassium. Use Caution/Monitor.
mefenamic acid decreases effects of irbesartan by pharmacodynamic antagonism. Modify Therapy/Monitor Closely. NSAIDs decrease synthesis of vasodilating renal prostaglandins, and thus affect fluid homeostasis and may diminish antihypertensive effect.
irbesartan, mefenamic acid. Either increases toxicity of the other by Other (see comment). Use Caution/Monitor. Comment: May result in renal function deterioration, particularly in elderly or volume depleted individuals. - isoproterenol
mefenamic acid increases and isoproterenol decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- ketoprofen
ketoprofen and mefenamic acid both increase anticoagulation. Use Caution/Monitor.
ketoprofen and mefenamic acid both increase serum potassium. Use Caution/Monitor. - ketorolac
ketorolac and mefenamic acid both increase anticoagulation. Use Caution/Monitor.
ketorolac and mefenamic acid both increase serum potassium. Use Caution/Monitor. - ketorolac intranasal
ketorolac intranasal and mefenamic acid both increase anticoagulation. Use Caution/Monitor.
ketorolac intranasal and mefenamic acid both increase serum potassium. Use Caution/Monitor. - labetalol
labetalol and mefenamic acid both increase serum potassium. Use Caution/Monitor.
mefenamic acid decreases effects of labetalol by pharmacodynamic antagonism. Use Caution/Monitor. Long term (>1 wk) NSAID use. NSAIDs decrease prostaglandin synthesis. - lacosamide
mefenamic acid increases levels of lacosamide by affecting hepatic enzyme CYP2C9/10 metabolism. Modify Therapy/Monitor Closely. Consider decreasing lacosamide dose when coadministered with strong CYP2C9 inhibitors.
- latanoprost
latanoprost, mefenamic acid. unspecified interaction mechanism. Use Caution/Monitor. There are conflicting reports from studies of either increased or decreased IOP when ophthalmic prostaglandins are coadministered with NSAIDs (either systemic or ophthalmic).
- latanoprostene bunod ophthalmic
latanoprostene bunod ophthalmic, mefenamic acid. unspecified interaction mechanism. Use Caution/Monitor. There are conflicting reports from studies of either increased or decreased IOP when ophthalmic prostaglandins are coadministered with NSAIDs (either systemic or ophthalmic).
- lesinurad
mefenamic acid will increase the level or effect of lesinurad by affecting hepatic enzyme CYP2C9/10 metabolism. Modify Therapy/Monitor Closely.
- levalbuterol
mefenamic acid increases and levalbuterol decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- levofloxacin
levofloxacin, mefenamic acid. Other (see comment). Modify Therapy/Monitor Closely. Comment: Risk of CNS stimulation/seizure. Mechanism: Displacement of GABA from receptors in brain.
- levomilnacipran
levomilnacipran, mefenamic acid. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. SNRIs may further impair platelet activity in patients taking antiplatelet or anticoagulant drugs.
- lisinopril
lisinopril, mefenamic acid. Either increases toxicity of the other by Other (see comment). Use Caution/Monitor. Comment: May result in renal function deterioration, particularly in elderly or volume depleted individuals.
- lithium
mefenamic acid increases levels of lithium by decreasing renal clearance. Use Caution/Monitor.
- lornoxicam
lornoxicam and mefenamic acid both increase anticoagulation. Use Caution/Monitor.
lornoxicam and mefenamic acid both increase serum potassium. Use Caution/Monitor. - losartan
losartan and mefenamic acid both increase serum potassium. Use Caution/Monitor.
mefenamic acid decreases effects of losartan by pharmacodynamic antagonism. Modify Therapy/Monitor Closely. NSAIDs decrease synthesis of vasodilating renal prostaglandins, and thus affect fluid homeostasis and may diminish antihypertensive effect.
losartan, mefenamic acid. Either increases toxicity of the other by Other (see comment). Use Caution/Monitor. Comment: May result in renal function deterioration, particularly in elderly or volume depleted individuals. - meclofenamate
meclofenamate and mefenamic acid both increase anticoagulation. Use Caution/Monitor.
meclofenamate and mefenamic acid both increase serum potassium. Use Caution/Monitor. - melatonin
melatonin increases effects of mefenamic acid by anticoagulation. Use Caution/Monitor. Melatonin may decrease prothrombin time.
- meloxicam
mefenamic acid and meloxicam both increase anticoagulation. Use Caution/Monitor.
mefenamic acid and meloxicam both increase serum potassium. Use Caution/Monitor. - mesalamine
mesalamine, mefenamic acid. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Additive nephrotoxicity.
- metaproterenol
mefenamic acid increases and metaproterenol decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- methyclothiazide
mefenamic acid increases and methyclothiazide decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor. .
- methylprednisolone
mefenamic acid, methylprednisolone. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of GI ulceration.
- metolazone
mefenamic acid increases and metolazone decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- metoprolol
metoprolol and mefenamic acid both increase serum potassium. Use Caution/Monitor.
mefenamic acid decreases effects of metoprolol by pharmacodynamic antagonism. Use Caution/Monitor. Long term (>1 wk) NSAID use. NSAIDs decrease prostaglandin synthesis. - milnacipran
milnacipran, mefenamic acid. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of upper GI bleeding. SSRIs inhib. serotonin uptake by platelets.
- mistletoe
mefenamic acid increases and mistletoe decreases anticoagulation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- moexipril
moexipril, mefenamic acid. Either increases toxicity of the other by Other (see comment). Use Caution/Monitor. Comment: May result in renal function deterioration, particularly in elderly or volume depleted individuals.
- moxifloxacin
moxifloxacin, mefenamic acid. Other (see comment). Modify Therapy/Monitor Closely. Comment: Increased risk of CNS stimulation and seizures with high doses of fluoroquinolones.
- moxisylyte
mefenamic acid decreases effects of moxisylyte by pharmacodynamic antagonism. Use Caution/Monitor. NSAIDs decrease prostaglandin synthesis.
- mycophenolate
mefenamic acid will increase the level or effect of mycophenolate by acidic (anionic) drug competition for renal tubular clearance. Use Caution/Monitor.
- nabumetone
mefenamic acid and nabumetone both increase anticoagulation. Use Caution/Monitor.
mefenamic acid and nabumetone both increase serum potassium. Use Caution/Monitor. - nadolol
nadolol and mefenamic acid both increase serum potassium. Use Caution/Monitor.
mefenamic acid decreases effects of nadolol by pharmacodynamic antagonism. Use Caution/Monitor. Long term (>1 wk) NSAID use. NSAIDs decrease prostaglandin synthesis. - naproxen
mefenamic acid and naproxen both increase anticoagulation. Use Caution/Monitor.
mefenamic acid and naproxen both increase serum potassium. Use Caution/Monitor. - nebivolol
nebivolol and mefenamic acid both increase serum potassium. Use Caution/Monitor.
mefenamic acid decreases effects of nebivolol by pharmacodynamic antagonism. Use Caution/Monitor. Long term (>1 wk) NSAID use. NSAIDs decrease prostaglandin synthesis. - nefazodone
nefazodone, mefenamic acid. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of upper GI bleeding. SSRIs inhib. serotonin uptake by platelets.
- nettle
mefenamic acid increases and nettle decreases anticoagulation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- norepinephrine
mefenamic acid increases and norepinephrine decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- olmesartan
olmesartan and mefenamic acid both increase serum potassium. Use Caution/Monitor.
mefenamic acid decreases effects of olmesartan by pharmacodynamic antagonism. Modify Therapy/Monitor Closely. NSAIDs decrease synthesis of vasodilating renal prostaglandins, and thus affect fluid homeostasis and may diminish antihypertensive effect.
olmesartan, mefenamic acid. Either increases toxicity of the other by Other (see comment). Use Caution/Monitor. Comment: May result in renal function deterioration, particularly in elderly or volume depleted individuals. - ospemifene
mefenamic acid increases levels of ospemifene by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor.
mefenamic acid, ospemifene. Either increases levels of the other by plasma protein binding competition. Modify Therapy/Monitor Closely. - oxaprozin
mefenamic acid and oxaprozin both increase anticoagulation. Use Caution/Monitor.
mefenamic acid and oxaprozin both increase serum potassium. Use Caution/Monitor. - panax ginseng
mefenamic acid and panax ginseng both increase anticoagulation. Use Caution/Monitor.
- parecoxib
mefenamic acid and parecoxib both increase anticoagulation. Use Caution/Monitor.
mefenamic acid and parecoxib both increase serum potassium. Use Caution/Monitor. - paroxetine
paroxetine, mefenamic acid. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of upper GI bleeding. SSRIs inhib. serotonin uptake by platelets.
- pau d'arco
mefenamic acid and pau d'arco both increase anticoagulation. Use Caution/Monitor.
- pegaspargase
pegaspargase increases effects of mefenamic acid by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of bleeding events.
- penbutolol
penbutolol and mefenamic acid both increase serum potassium. Use Caution/Monitor.
mefenamic acid decreases effects of penbutolol by pharmacodynamic antagonism. Use Caution/Monitor. Long term (>1 wk) NSAID use. NSAIDs decrease prostaglandin synthesis. - perindopril
perindopril, mefenamic acid. Either increases toxicity of the other by Other (see comment). Use Caution/Monitor. Comment: May result in renal function deterioration, particularly in elderly or volume depleted individuals.
- phenindione
phenindione and mefenamic acid both increase anticoagulation. Modify Therapy/Monitor Closely.
- phenoxybenzamine
mefenamic acid decreases effects of phenoxybenzamine by pharmacodynamic antagonism. Use Caution/Monitor. NSAIDs decrease prostaglandin synthesis.
- phentolamine
mefenamic acid decreases effects of phentolamine by pharmacodynamic antagonism. Use Caution/Monitor. NSAIDs decrease prostaglandin synthesis.
- phytoestrogens
mefenamic acid and phytoestrogens both increase anticoagulation. Use Caution/Monitor.
- pindolol
pindolol and mefenamic acid both increase serum potassium. Use Caution/Monitor.
mefenamic acid decreases effects of pindolol by pharmacodynamic antagonism. Use Caution/Monitor. Long term (>1 wk) NSAID use. NSAIDs decrease prostaglandin synthesis. - pirbuterol
mefenamic acid increases and pirbuterol decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- piroxicam
mefenamic acid and piroxicam both increase anticoagulation. Use Caution/Monitor.
mefenamic acid and piroxicam both increase serum potassium. Use Caution/Monitor. - pivmecillinam
pivmecillinam, mefenamic acid. Either increases levels of the other by plasma protein binding competition. Use Caution/Monitor.
pivmecillinam, mefenamic acid. Either increases levels of the other by decreasing renal clearance. Use Caution/Monitor. - potassium acid phosphate
mefenamic acid and potassium acid phosphate both increase serum potassium. Modify Therapy/Monitor Closely.
- potassium chloride
mefenamic acid and potassium chloride both increase serum potassium. Modify Therapy/Monitor Closely.
- potassium citrate
mefenamic acid and potassium citrate both increase serum potassium. Modify Therapy/Monitor Closely.
- potassium iodide
potassium iodide and mefenamic acid both increase serum potassium. Use Caution/Monitor.
- pralatrexate
mefenamic acid increases levels of pralatrexate by decreasing renal clearance. Use Caution/Monitor. NSAIDs may delay pralatrexate clearance, increasing drug exposure. Adjust the pralatrexate dose as needed.
- prasugrel
mefenamic acid, prasugrel. Either increases effects of the other by anticoagulation. Use Caution/Monitor. Chronic use of NSAIDs with prasugrel may increase bleeding risk.
- prazosin
mefenamic acid decreases effects of prazosin by pharmacodynamic antagonism. Use Caution/Monitor. NSAIDs decrease prostaglandin synthesis.
- prednisolone
mefenamic acid, prednisolone. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of GI ulceration.
- prednisone
mefenamic acid, prednisone. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of GI ulceration.
- probenecid
mefenamic acid will increase the level or effect of probenecid by acidic (anionic) drug competition for renal tubular clearance. Use Caution/Monitor.
- propranolol
propranolol and mefenamic acid both increase serum potassium. Use Caution/Monitor.
mefenamic acid decreases effects of propranolol by pharmacodynamic antagonism. Use Caution/Monitor. Long term (>1 wk) NSAID use. NSAIDs decrease prostaglandin synthesis. - protamine
protamine and mefenamic acid both increase anticoagulation. Modify Therapy/Monitor Closely.
- quinapril
quinapril, mefenamic acid. Either increases toxicity of the other by Other (see comment). Use Caution/Monitor. Comment: May result in renal function deterioration, particularly in elderly or volume depleted individuals.
- ramipril
ramipril, mefenamic acid. Either increases toxicity of the other by Other (see comment). Use Caution/Monitor. Comment: May result in renal function deterioration, particularly in elderly or volume depleted individuals.
- reishi
mefenamic acid and reishi both increase anticoagulation. Use Caution/Monitor.
- reteplase
mefenamic acid and reteplase both increase anticoagulation. Use Caution/Monitor. Potential for increased risk of bleeding, caution is advised.
- rivaroxaban
rivaroxaban, mefenamic acid. Other (see comment). Use Caution/Monitor. Comment: NSAIDs are known to increase bleeding. Bleeding risk may be increased when NSAIDs are used concomitantly with rivaroxaban. Monitor for signs/symptoms of blood loss.
- rivastigmine
rivastigmine increases toxicity of mefenamic acid by pharmacodynamic synergism. Use Caution/Monitor. Monitor patients for symptoms of active or occult gastrointestinal bleeding.
- sacubitril/valsartan
sacubitril/valsartan and mefenamic acid both increase serum potassium. Use Caution/Monitor.
sacubitril/valsartan, mefenamic acid. Either increases toxicity of the other by Other (see comment). Use Caution/Monitor. Comment: May result in renal function deterioration, particularly in elderly or volume depleted individuals.
mefenamic acid decreases effects of sacubitril/valsartan by pharmacodynamic antagonism. Modify Therapy/Monitor Closely. NSAIDs decrease synthesis of vasodilating renal prostaglandins, and thus affect fluid homeostasis and may diminish antihypertensive effect. - salicylates (non-asa)
mefenamic acid and salicylates (non-asa) both increase anticoagulation. Use Caution/Monitor.
mefenamic acid and salicylates (non-asa) both increase serum potassium. Use Caution/Monitor. - salmeterol
mefenamic acid increases and salmeterol decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- salsalate
mefenamic acid and salsalate both increase anticoagulation. Use Caution/Monitor.
mefenamic acid and salsalate both increase serum potassium. Use Caution/Monitor. - saw palmetto
saw palmetto increases toxicity of mefenamic acid by unspecified interaction mechanism. Use Caution/Monitor. May increase risk of bleeding.
- sertraline
sertraline, mefenamic acid. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of upper GI bleeding. SSRIs inhib. serotonin uptake by platelets.
- Siberian ginseng
mefenamic acid and Siberian ginseng both increase anticoagulation. Use Caution/Monitor.
- silodosin
mefenamic acid decreases effects of silodosin by pharmacodynamic antagonism. Use Caution/Monitor. NSAIDs decrease prostaglandin synthesis.
- sodium picosulfate/magnesium oxide/anhydrous citric acid
mefenamic acid, sodium picosulfate/magnesium oxide/anhydrous citric acid. Either increases toxicity of the other by Other (see comment). Use Caution/Monitor. Comment: May be associated with fluid and electrolyte imbalances.
- sodium sulfate/?magnesium sulfate/potassium chloride
sodium sulfate/?magnesium sulfate/potassium chloride increases toxicity of mefenamic acid 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 mefenamic acid 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/polyethylene glycol
mefenamic acid, sodium sulfate/potassium sulfate/magnesium sulfate/polyethylene glycol. Other (see comment). Use Caution/Monitor. Comment: Caution when bowel preps are used with drugs that cause SIADH or NSAIDs; increased risk for water retention or electrolyte imbalance.
- sotalol
sotalol and mefenamic acid both increase serum potassium. Use Caution/Monitor.
mefenamic acid decreases effects of sotalol by pharmacodynamic antagonism. Use Caution/Monitor. Long term (>1 wk) NSAID use. NSAIDs decrease prostaglandin synthesis. - sparsentan
mefenamic acid and sparsentan both increase nephrotoxicity and/or ototoxicity. Use Caution/Monitor. Coadministration of NSAIDS, including selective COX-2 inhibitors, may result in deterioration of kidney function (eg, possible kidney failure). Monitor for signs of worsening renal function with concomitant use with NSAIDs.
- spironolactone
spironolactone and mefenamic acid both increase serum potassium. Modify Therapy/Monitor Closely.
- succinylcholine
mefenamic acid and succinylcholine both increase serum potassium. Use Caution/Monitor.
- sulfasalazine
mefenamic acid and sulfasalazine both increase anticoagulation. Use Caution/Monitor.
mefenamic acid and sulfasalazine both increase serum potassium. Use Caution/Monitor. - sulindac
mefenamic acid and sulindac both increase anticoagulation. Use Caution/Monitor.
mefenamic acid and sulindac both increase serum potassium. Use Caution/Monitor. - tafluprost
tafluprost, mefenamic acid. unspecified interaction mechanism. Use Caution/Monitor. There are conflicting reports from studies of either increased or decreased IOP when ophthalmic prostaglandins are coadministered with NSAIDs (either systemic or ophthalmic).
- telmisartan
telmisartan and mefenamic acid both increase serum potassium. Use Caution/Monitor.
mefenamic acid decreases effects of telmisartan by pharmacodynamic antagonism. Modify Therapy/Monitor Closely. NSAIDs decrease synthesis of vasodilating renal prostaglandins, and thus affect fluid homeostasis and may diminish antihypertensive effect.
telmisartan, mefenamic acid. Either increases toxicity of the other by Other (see comment). Use Caution/Monitor. Comment: May result in renal function deterioration, particularly in elderly or volume depleted individuals. - temocillin
temocillin, mefenamic acid. Either increases levels of the other by plasma protein binding competition. Use Caution/Monitor.
temocillin, mefenamic acid. Either increases levels of the other by decreasing renal clearance. Use Caution/Monitor. - tenecteplase
mefenamic acid and tenecteplase both increase anticoagulation. Use Caution/Monitor. Potential for increased risk of bleeding, caution is advised.
- tenofovir DF
tenofovir DF, mefenamic acid. Either increases levels of the other by decreasing renal clearance. Modify Therapy/Monitor Closely. Toxicity may result from coadministration of tenofovir DF with other drugs that are also primarily excreted by glomerular filtration and/or active tubular secretion including high-dose or multiple-dose NSAIDs; alternatives to NSAIDs should be considered.
- terazosin
mefenamic acid decreases effects of terazosin by pharmacodynamic antagonism. Use Caution/Monitor. NSAIDs decrease prostaglandin synthesis.
- terbinafine
mefenamic acid will increase the level or effect of terbinafine by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor.
- terbutaline
mefenamic acid increases and terbutaline decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- ticagrelor
ticagrelor, mefenamic acid. Either increases effects of the other by anticoagulation. Use Caution/Monitor. Increased risk of bleeding with use of ticagrelor and chronic NSAID use. .
- ticarcillin
ticarcillin, mefenamic acid. Either increases levels of the other by plasma protein binding competition. Use Caution/Monitor.
ticarcillin, mefenamic acid. Either increases levels of the other by decreasing renal clearance. Use Caution/Monitor. - timolol
timolol and mefenamic acid both increase serum potassium. Use Caution/Monitor.
mefenamic acid decreases effects of timolol by pharmacodynamic antagonism. Use Caution/Monitor. Long term (>1 wk) NSAID use. NSAIDs decrease prostaglandin synthesis. - tobramycin inhaled
tobramycin inhaled and mefenamic acid both increase nephrotoxicity and/or ototoxicity. Modify Therapy/Monitor Closely. Avoid concurrent or sequential use to decrease risk for ototoxicity
- tolazamide
mefenamic acid increases effects of tolazamide by unknown mechanism. Use Caution/Monitor. Risk of hypoglycemia.
- tolbutamide
mefenamic acid increases effects of tolbutamide by unknown mechanism. Use Caution/Monitor. Risk of hypoglycemia.
- tolfenamic acid
mefenamic acid and tolfenamic acid both increase anticoagulation. Use Caution/Monitor.
mefenamic acid and tolfenamic acid both increase serum potassium. Use Caution/Monitor. - tolmetin
mefenamic acid and tolmetin both increase anticoagulation. Use Caution/Monitor.
mefenamic acid and tolmetin both increase serum potassium. Use Caution/Monitor. - tolvaptan
mefenamic acid and tolvaptan both increase serum potassium. Use Caution/Monitor.
- torsemide
mefenamic acid increases and torsemide decreases serum potassium. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- trandolapril
trandolapril, mefenamic acid. Either increases toxicity of the other by Other (see comment). Use Caution/Monitor. Comment: May result in renal function deterioration, particularly in elderly or volume depleted individuals.
- travoprost ophthalmic
travoprost ophthalmic, mefenamic acid. unspecified interaction mechanism. Use Caution/Monitor. There are conflicting reports from studies of either increased or decreased IOP when ophthalmic prostaglandins are coadministered with NSAIDs (either systemic or ophthalmic).
- trazodone
trazodone, mefenamic acid. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of upper GI bleeding. SSRIs inhib. serotonin uptake by platelets.
- triamcinolone acetonide injectable suspension
mefenamic acid, triamcinolone acetonide injectable suspension. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Concomitant use of NSAIDS and corticosteroids increases the risk of gastrointestinal side effects. .
- triamterene
triamterene and mefenamic acid both increase serum potassium. Modify Therapy/Monitor Closely.
- valsartan
valsartan and mefenamic acid both increase serum potassium. Use Caution/Monitor.
mefenamic acid decreases effects of valsartan by pharmacodynamic antagonism. Modify Therapy/Monitor Closely. NSAIDs decrease synthesis of vasodilating renal prostaglandins, and thus affect fluid homeostasis and may diminish antihypertensive effect.
valsartan, mefenamic acid. Either increases toxicity of the other by Other (see comment). Use Caution/Monitor. Comment: May result in renal function deterioration, particularly in elderly or volume depleted individuals. - venlafaxine
venlafaxine, mefenamic acid. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of upper GI bleeding. SSRIs inhib. serotonin uptake by platelets.
- vitamin K1 (phytonadione)
mefenamic acid increases and vitamin K1 (phytonadione) decreases anticoagulation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- voclosporin
voclosporin, mefenamic acid. Either increases toxicity of the other by nephrotoxicity and/or ototoxicity. Modify Therapy/Monitor Closely. Coadministration with drugs associated with nephrotoxicity may increase the risk for acute and/or chronic nephrotoxicity.
- vorapaxar
mefenamic acid, vorapaxar. Either increases effects of the other by pharmacodynamic synergism. Use Caution/Monitor. Additive antiplatelet effect may occur.
- vortioxetine
mefenamic acid, vortioxetine. Either increases effects of the other by anticoagulation. Use Caution/Monitor.
- warfarin
mefenamic acid, warfarin. Either increases effects of the other by pharmacodynamic synergism. Modify Therapy/Monitor Closely. Drugs with antiplatelet properties may increase anticoagulation effect of warfarin.
- zanubrutinib
mefenamic acid, zanubrutinib. Either increases effects of the other by anticoagulation. Modify Therapy/Monitor Closely. Zanubrutinib-induced cytopenias increases risk of hemorrhage. Coadministration of zanubritinib with antiplatelets or anticoagulants may further increase this risk.
- zotepine
mefenamic acid decreases effects of zotepine by pharmacodynamic antagonism. Use Caution/Monitor. NSAIDs decrease prostaglandin synthesis.
Minor (76)
- aceclofenac
aceclofenac will increase the level or effect of mefenamic acid by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.
- acemetacin
acemetacin will increase the level or effect of mefenamic acid by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.
- acyclovir
mefenamic acid will increase the level or effect of acyclovir by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.
- alendronate
mefenamic acid, alendronate. Either increases toxicity of the other by pharmacodynamic synergism. Minor/Significance Unknown. Increased risk of GI ulceration.
- amikacin
mefenamic acid increases levels of amikacin by decreasing renal clearance. Minor/Significance Unknown. Interaction mainly occurs in preterm infants.
- aminohippurate sodium
mefenamic acid will increase the level or effect of aminohippurate sodium by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.
- anamu
mefenamic acid and anamu both increase anticoagulation. Minor/Significance Unknown.
- aspirin
aspirin will increase the level or effect of mefenamic acid by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.
- aspirin rectal
aspirin rectal will increase the level or effect of mefenamic acid by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.
- aspirin/citric acid/sodium bicarbonate
aspirin/citric acid/sodium bicarbonate will increase the level or effect of mefenamic acid by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.
- balsalazide
mefenamic acid will increase the level or effect of balsalazide by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.
- bendroflumethiazide
bendroflumethiazide will increase the level or effect of mefenamic acid by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.
- cefadroxil
cefadroxil will increase the level or effect of mefenamic acid by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.
- cefamandole
cefamandole will increase the level or effect of mefenamic acid by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.
- cefpirome
cefpirome will increase the level or effect of mefenamic acid by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.
- ceftibuten
ceftibuten will increase the level or effect of mefenamic acid by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.
- celecoxib
celecoxib will increase the level or effect of mefenamic acid by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.
- cephalexin
cephalexin will increase the level or effect of mefenamic acid by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.
- chlorothiazide
chlorothiazide will increase the level or effect of mefenamic acid by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.
- chlorpropamide
mefenamic acid will increase the level or effect of chlorpropamide by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.
- chlorthalidone
chlorthalidone will increase the level or effect of mefenamic acid by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.
- choline magnesium trisalicylate
mefenamic acid will increase the level or effect of choline magnesium trisalicylate by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.
- creatine
creatine, mefenamic acid. Mechanism: pharmacodynamic synergism. Minor/Significance Unknown. (Theoretical interaction) Combination may have additive nephrotoxic effects.
- cyclopenthiazide
cyclopenthiazide will increase the level or effect of mefenamic acid by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.
- danshen
mefenamic acid and danshen both increase anticoagulation. Minor/Significance Unknown.
- devil's claw
mefenamic acid and devil's claw both increase anticoagulation. Minor/Significance Unknown.
- diclofenac
diclofenac will increase the level or effect of mefenamic acid by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.
- diclofenac topical
diclofenac topical, mefenamic acid. Either increases effects of the other by pharmacodynamic synergism. Minor/Significance Unknown. Although low, there is systemic exposure to diclofenac topical; theoretically, concomitant administration with systemic NSAIDS or aspirin may result in increased NSAID adverse effects.
- diflunisal
diflunisal will increase the level or effect of mefenamic acid by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.
- entecavir
mefenamic acid, entecavir. Either increases effects of the other by decreasing renal clearance. Minor/Significance Unknown. Coadministration with drugs that reduce renal function or compete for active tubular secretion may increase serum concentrations of either entecavir or the coadministered drug.
- eplerenone
mefenamic acid decreases effects of eplerenone by pharmacodynamic antagonism. Minor/Significance Unknown. NSAIDs decrease prostaglandin synthesis.
- etodolac
etodolac will increase the level or effect of mefenamic acid by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.
- fenoprofen
fenoprofen will increase the level or effect of mefenamic acid by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.
- feverfew
mefenamic acid decreases effects of feverfew by pharmacodynamic antagonism. Minor/Significance Unknown.
- flurbiprofen
flurbiprofen will increase the level or effect of mefenamic acid by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.
- furosemide
mefenamic acid decreases effects of furosemide by pharmacodynamic antagonism. Minor/Significance Unknown. NSAIDs decrease prostaglandin synthesis.
- ganciclovir
mefenamic acid will increase the level or effect of ganciclovir by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.
- gentamicin
mefenamic acid increases levels of gentamicin by decreasing renal clearance. Minor/Significance Unknown. Interaction mainly occurs in preterm infants.
- hydrochlorothiazide
hydrochlorothiazide will increase the level or effect of mefenamic acid by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.
- ibuprofen
ibuprofen will increase the level or effect of mefenamic acid by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.
- ibuprofen IV
ibuprofen IV will increase the level or effect of mefenamic acid by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.
- imidapril
mefenamic acid decreases effects of imidapril by pharmacodynamic antagonism. Minor/Significance Unknown. NSAIDs decrease prostaglandin synthesis.
- indapamide
indapamide will increase the level or effect of mefenamic acid by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.
- indomethacin
indomethacin will increase the level or effect of mefenamic acid by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.
- ketoprofen
ketoprofen will increase the level or effect of mefenamic acid by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.
- ketorolac
ketorolac will increase the level or effect of mefenamic acid by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.
- ketorolac intranasal
ketorolac intranasal will increase the level or effect of mefenamic acid by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.
- lornoxicam
lornoxicam will increase the level or effect of mefenamic acid by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.
- meclofenamate
meclofenamate will increase the level or effect of mefenamic acid by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.
- meloxicam
mefenamic acid will increase the level or effect of meloxicam by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.
- mesalamine
mefenamic acid will increase the level or effect of mesalamine by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.
- methyclothiazide
methyclothiazide will increase the level or effect of mefenamic acid by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.
- metolazone
metolazone will increase the level or effect of mefenamic acid by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.
- nabumetone
mefenamic acid will increase the level or effect of nabumetone by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.
- naproxen
mefenamic acid will increase the level or effect of naproxen by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.
- neomycin PO
mefenamic acid increases levels of neomycin PO by decreasing renal clearance. Minor/Significance Unknown. Interaction mainly occurs in preterm infants.
- nitazoxanide
nitazoxanide, mefenamic acid. Either increases levels of the other by Mechanism: plasma protein binding competition. Minor/Significance Unknown.
- noni juice
mefenamic acid and noni juice both increase serum potassium. Minor/Significance Unknown.
- ofloxacin
ofloxacin, mefenamic acid. Other (see comment). Minor/Significance Unknown. Comment: Risk of CNS stimulation/seizure. Mechanism: Displacement of GABA from receptors in brain.
- oxaprozin
mefenamic acid will increase the level or effect of oxaprozin by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.
- parecoxib
mefenamic acid will increase the level or effect of parecoxib by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.
- paromomycin
mefenamic acid increases levels of paromomycin by decreasing renal clearance. Minor/Significance Unknown. Interaction mainly occurs in preterm infants.
- piroxicam
mefenamic acid will increase the level or effect of piroxicam by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.
- rose hips
rose hips will increase the level or effect of mefenamic acid by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.
- salicylates (non-asa)
mefenamic acid will increase the level or effect of salicylates (non-asa) by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.
- salsalate
mefenamic acid will increase the level or effect of salsalate by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.
- streptomycin
mefenamic acid increases levels of streptomycin by decreasing renal clearance. Minor/Significance Unknown. Interaction mainly occurs in preterm infants.
- sulfasalazine
mefenamic acid will increase the level or effect of sulfasalazine by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.
- sulindac
mefenamic acid will increase the level or effect of sulindac by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.
- tobramycin
mefenamic acid increases levels of tobramycin by decreasing renal clearance. Minor/Significance Unknown. Interaction mainly occurs in preterm infants.
- tolfenamic acid
mefenamic acid will increase the level or effect of tolfenamic acid by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.
- tolmetin
mefenamic acid will increase the level or effect of tolmetin by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.
- triamterene
triamterene, mefenamic acid. Other (see comment). Minor/Significance Unknown. Comment: Risk of acute renal failure. Mechanism: NSAIDs decrease prostaglandin synthesis, which normally protect against nephrotoxicity.
mefenamic acid increases toxicity of triamterene by pharmacodynamic antagonism. Minor/Significance Unknown. NSAIDs decrease prostaglandin synthesis, increasing the risk of nephrotoxicity. - valganciclovir
mefenamic acid will increase the level or effect of valganciclovir by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.
- vancomycin
mefenamic acid increases levels of vancomycin by decreasing renal clearance. Minor/Significance Unknown. Interaction mainly occurs in neonates.
- willow bark
mefenamic acid will increase the level or effect of willow bark by acidic (anionic) drug competition for renal tubular clearance. Minor/Significance Unknown.
Adverse Effects
>10%
Borderline elevations of one or more LFTs (<15%)
1-10%
Abdominal pain
Anorexia
Diarrhea
Nausea
Pyrosis
Gastritis
Flatulence
Constipation
Steatorrhea
Upper GI ulcers, gross bleeding/perforation (1% of patients treated for 3-6 mth and 2-4% of those treated for 1 yo)
<1%
Leukopenia
Eosinophilia
Thrombocytopenic purpura
Agranulocytosis
Pancytopenia
Bone marrow hypoplasia
Renal failure (including papillary necrosis & acute interstitial nephritis)
Acute interstitial nephritis has been associated with hematuria, proteinuria, & nephrotic syndrome
Warnings
Black Box Warnings
Cardiovascular risk
- NSAIDs may increase risk of serious cardiovascular thrombotic events, myocardial infarction (MI), & stroke, which can be fatal
- Risk may increase with duration of use
- Patients with risk factors for or existing cardiovascular disease may be at greater risk
- NSAIDs are contraindicated for perioperative pain in the setting of coronary artery bypass graft (CABG) surgery (increased risk of MI & stroke)
Gastrointestinal risk
- NSAIDs increase risk of serious GI adverse events including bleeding, ulceration, & perforation of the stomach or intestines, which can be fatal
- GI adverse events may occur at any time during use & without warning symptoms
- Elderly patients are at greater risk for serious GI events
Contraindications
Hypersensitivity, ASA allergy, history of aspirin triad, GI tract ulcer/inflammation, CABG, renal dz, late pregnancy (may cause premature closure of ductus arteriosus)
Cautions
Use caution in anemia, bronchospasm, cardiac disease, CHF, HTN, SLE, fluid retention, hepatic/renal impairment, bleeding diathesis
If severe diarrhea occurs, reduce dose or temporarily discontinue drug
Therapy may cause premature closure of ductus arteriosus; avoid use in pregnant women starting at 30 weeks of gestation (third trimester)
Mefenamic acid cannot be expected to substitute for corticosteroids or to treat corticosteroid insufficiency; abrupt discontinuation of corticosteroids may lead to disease exacerbation; patients on prolonged corticosteroid therapy should have therapy tapered slowly if a decision is made to discontinue corticosteroid
Drug associated with anaphylactic reactions in patients with and without known hypersensitivity to mefenamic acid and in patients with aspirin-sensitive asthma
Therapy can lead to new onset of hypertension or worsening of preexisting hypertension, either of which may contribute to increased incidence of CV events; patients taking angiotensin-converting enzyme (ACE) inhibitors, thiazides diuretics, or loop diuretics may have impaired response to these therapies when taking this medication; monitor blood pressure during initiation of treatment and throughout course of therapy
Increases in serum potassium concentration, including hyperkalemia, reported with use, even in some patients without renal impairment; in patients with normal renal function, these effects have been attributed to a hyporeninemic-hypoaldosteronism state
Exacerbation of asthma-related to aspirin sensitivity
- A subpopulation of patients with asthma may have aspirin-sensitive asthma which may include chronic rhinosinusitis complicated by nasal polyps; severe, potentially fatal bronchospasm and/or intolerance to aspirin and other NSAIDs
- Because cross-reactivity between aspirin and other NSAIDs has been reported in aspirin-sensitive patients, therapy is contraindicated in patients with this sensitivity
- When drug is used in patients with pre-existing asthma (without known aspirin sensitivity), monitor patients for changes in signs and symptoms of asthma
Cardiovascular thrombotic events
- Relative increase in serious CV thrombotic events over baseline conferred by NSAID use appears to be similar in those with and without known CV disease or risk factors for CV disease; however, patients with known CV disease or risk factors had higher absolute incidence of excess serious CV thrombotic events, due to their increased baseline rate
- Some observational studies found that increased risk of serious CV thrombotic events began as early as the first weeks of treatment; increase in CV thrombotic risk has been observed most consistently at higher doses
- To minimize the potential risk for an adverse CV event in NSAID-treated patients, use the lowest effective dose for the shortest duration possible
- Physicians and patients should remain alert for development of such events throughout entire treatment course, even in absence of previous CV symptoms
- Patients should be informed about the symptoms of serious CV events and the steps to take if they occur
- There is no consistent evidence that concurrent use of aspirin mitigates increased risk of serious CV thrombotic events associated with NSAID use; the concurrent use of aspirin and an NSAID, such as mefenamic acid, increases risk of serious gastrointestinal (GI) event
Postmyocardial infarction patients
- Observational studies conducted in the Danish National Registry have demonstrated that patients treated with NSAIDs in the post-MI period were at increased risk of reinfarction, CV-related death, and all-cause mortality beginning in first week of treatment
- Avoid use of mefenamic acid in patients with a recent MI unless benefits are expected to outweigh risk of recurrent CV thrombotic events; if mefenamic acid is used in patients with a recent MI, monitor patients for signs of cardiac ischemia
Hepatotoxicity
- Elevations of ALT or AST (three or more times the upper limit of normal [ULN]) reported
- Rare, sometimes fatal, cases of severe hepatic injury, including fulminant hepatitis, liver necrosis, and hepatic failure reported
- Elevations of ALT or AST (less than three times ULN) may occur
- Inform patients of warning signs and symptoms of hepatotoxicity (eg, nausea, fatigue, lethargy, diarrhea, pruritus, jaundice, right upper quadrant tenderness, and "flu-like" symptoms)
- If clinical signs and symptoms consistent with liver disease develop, or if systemic manifestations occur (eg, eosinophilia, rash, etc.), discontinue therapy immediately, and perform a clinical evaluation of the patient
Renal toxicity
- Long-term administration of NSAIDs has resulted in renal papillary necrosis and other renal injury
- Renal toxicity also seen in patients in whom renal prostaglandins have a compensatory role in the maintenance of renal perfusion; in these patients, administration of an NSAID may cause a dose-dependent reduction in prostaglandin formation and, secondarily, in renal blood flow, which may precipitate overt renal decompensation
- Patients at greatest risk of this reaction are those with impaired renal function, dehydration, hypovolemia, heart failure, liver dysfunction, those taking diuretics and ACE inhibitors or ARBs, and the elderly
- Discontinuation of therapy is usually followed by recovery to pretreatment state; no information is available from controlled clinical studies regarding use of mefenamic acid in patients with advanced renal disease
- The renal effects of mefenamic acid may hasten progression of renal dysfunction in patients with pre-existing renal disease; correct volume status in dehydrated or hypovolemic patients prior to initiating mefenamic acid
- Monitor renal function in patients with renal or hepatic impairment, heart failure, dehydration, or hypovolemia during use of mefenamic acid
- Avoid use of mefenamic acid in patients with advanced renal disease unless benefits are expected to outweigh risk of worsening renal function
- If mefenamic acid is used in patients with advanced renal disease, monitor patients for signs of worsening renal function
Serious skin reactions
- Therapy can cause serious skin adverse reactions such as drug reaction with eosinophilia and systemic symptoms exfoliative dermatitis (DRESS), Stevens-Johnson Syndrome (SJS), and toxic epidermal necrolysis (TEN), which can be fatal
- Drug Reaction reported in patients taking NSAIDs; some of these events have been fatal or life-threatening; DRESS typically, although not exclusively, presents with fever, rash, lymphadenopathy, and/or facial swelling
- Other clinical manifestations may include hepatitis, nephritis, hematological abnormalities, myocarditis, or myositis; sometimes symptoms of DRESS may resemble an acute viral infection
- Eosinophilia is often present; because this disorder is variable in its presentation, other organ systems not noted here may be involved
- Early manifestations of hypersensitivity, such as fever or lymphadenopathy, may be present even though rash is not evident; if such signs or symptoms are present, discontinue therapy and evaluate the patient immediately
- These serious events may occur without warning; inform patients about the signs and symptoms of serious skin reactions and to discontinue use of mefenamic acid at first appearance of skin rash or any other sign of hypersensitivity
- Therapy is contraindicated in patients with previous serious skin reactions to NSAIDs
Hematologic toxicity
- Anemia has occurred in NSAID-treated patients; this may be due to occult or gross blood loss, fluid retention, or an incompletely described effect on erythropoiesis
- If a patient has any signs or symptoms of anemia, monitor hemoglobin or hematocrit; therapy may increase risk of bleeding events
- Co-morbid conditions such as coagulation disorders or concomitant use of warfarin, other anticoagulants, antiplatelet agents (eg, aspirin), serotonin reuptake inhibitors (SSRIs) and serotonin/norepinephrine reuptake inhibitors (SNRIs) may increase this risk; monitor for signs of bleeding
Heart Failure(HF) risk
- NSAIDS have the potential to trigger HF by prostaglandin inhibition that leads to sodium and water retention, increased systemic vascular resistance, and blunted response to diuretics
- Fluid retention and edema may occur
- Therapy may blunt CV effects of several therapeutic agents used to treat medical conditions (eg, diuretics, ACE inhibitors, or angiotensin receptor blockers)
- Avoid therapy in patients with severe heart failure unless benefits are expected to outweigh risk of worsening heart failure; if drug is used in patients with severe heart failure, monitor patients for signs of worsening heart failure
- NSAIDS should be avoided or withdrawn whenever possible
- AHA/ACC Heart Failure Guidelines; Circulation. 2016; 134
Risk factors for GI bleeding, ulceration, and perforation
- Even short-term NSAID therapy is not without risk
- Patients with a prior history of peptic ulcer disease and/or GI bleeding who used NSAIDs reported to ahve 10-fold increased risk for developing a GI bleed compared to patients without these risk factors
- Other factors that increase the risk for GI bleeding in patients treated with NSAIDs include longer duration of NSAID therapy, concomitant use of oral corticosteroids, aspirin, anticoagulants, or selective serotonin reuptake inhibitors (SSRIs); smoking, use of alcohol, older age, and poor general health status
- Most postmarketing reports of fatal GI events have occurred in elderly or debilitated patients; patients with advanced liver disease and/or coagulopathy are at increased risk for GI bleeding
-
Strategies to minimize GI risks in NSAID-treated patients
- Use lowest effective dosage for the shortest possible duration
- Avoid administration of more than one NSAID at a time
- Avoid use in patients at higher risk unless benefits are expected to outweigh increased risk of bleeding
- For such patients, as well as those with active GI bleeding, consider alternate therapies other than NSAIDs
- Remain alert for signs and symptoms of GI ulceration and bleeding during NSAID therapy
- If a serious GI adverse event is suspected, promptly initiate evaluation and treatment, and discontinue mefenamic acid until a serious GI adverse event is ruled out
- In the setting of concomitant use of low-dose aspirin for cardiac prophylaxis, monitor patients more closely for evidence of GI bleeding
Pregnancy & Lactation
Pregnancy
Use of NSAIDs can cause premature closure of fetal ductus arteriosus and fetal renal dysfunction leading to oligohydramnios and, in some cases, neonatal renal impairment
Because of these risks, limit dose and duration to between about 20 and 30 weeks of gestation, and avoid use at about 30 weeks of gestation and later in pregnancy
Use of NSAIDs, including mefenamic acid, at about 30 weeks gestation or later in pregnancy increases risk of premature closure of the fetal ductus arteriosus.
Data from observational studies regarding other potential embryofetal risks of NSAID use in women in first or second trimesters of pregnancy are inconclusive; based on animal data, prostaglandins have been shown to have important role in endometrial vascular permeability, blastocyst implantation, and decidualization
Animal data
- In animal studies, administration of prostaglandin synthesis inhibitors such as mefenamic acid, resulted in increased pre- and post-implantation loss
- Prostaglandins also have been shown to have important role in fetal kidney development; in published animal studies, prostaglandin synthesis inhibitors have been reported to impair kidney development when administered at clinically relevant doses
- Avoid use of NSAIDs in women at about 30 weeks gestation and later in pregnancy, because NSAIDs can cause premature closure of fetal ductus arteriosus
- If an NSAID is necessary at about 20 weeks gestation or later in pregnancy, limit use to lowest effective dose and shortest duration possible; if mefenamic acid treatment extends beyond 48 hours, consider monitoring with ultrasound for oligohydramnios; if oligohydramnios occurs, discontinue drug and follow up according to clinical practice
Labor and delivery
- In rat studies with NSAIDs, as with other drugs known to inhibit prostaglandin synthesis, an increased incidence of dystocia, delayed parturition, decreased pup survival occurred and increased the incidence of stillbirth’ the effects of mefenamic acid on labor and delivery in pregnant women are unknown
Infertility
- Based on the mechanism of action, use of prostaglandin-mediated NSAIDs, including mefenamic acid may delay or prevent rupture of ovarian follicles, which has been associated with reversible infertility in some women
- Published animal studies have shown that administration of prostaglandin synthesis inhibitors has potential to disrupt prostaglandin in mediated follicular rupture required for ovulation; small studies in women treated with NSAIDs have also shown a reversible delay in ovulation; consider withdrawal of NSAIDs, including mefenamic acid, in women who have difficulties conceiving or who are undergoing investigation of infertility.
Lactation
Trace amounts of mefenamic acid may be present in breast milk and transmitted to nursing infant; because of potential for serious adverse reactions in nursing infants from mefenamic acid, a decision should be made whether to discontinue nursing or to discontinue the drug, taking into account importance of drug to mother
Pregnancy Categories
A: Generally acceptable. Controlled studies in pregnant women show no evidence of fetal risk.
B: May be acceptable. Either animal studies show no risk but human studies not available or animal studies showed minor risks and human studies done and showed no risk. C: Use with caution if benefits outweigh risks. Animal studies show risk and human studies not available or neither animal nor human studies done. D: Use in LIFE-THREATENING emergencies when no safer drug available. Positive evidence of human fetal risk. X: Do not use in pregnancy. Risks involved outweigh potential benefits. Safer alternatives exist. NA: Information not available.Pharmacology
Mechanism of Action
Inhibits synthesis of prostaglandins in body tissues by inhibiting at least 2 cyclooxygenase isoenzymes, cyclooxygenase-1 (COX-1) and -2 (COX-2)
May inhibit chemotaxis, may alter lymphocyte activity, decrease proinflammatory cytokine activity, and may inhibit neutrophil aggregation. These effects may contribute to its anti-inflammatory activity
Pharmacokinetics
Half-life: 2 hr
Onset: Rapid
Peak Plasma Time: 2-4 hr (1 g dose); reached by the second day of administration (1 g dose, 4x daily)
Peak Plasma Concentration: 10 mcg/mL (1 g dose); 20 mcg/mL (1 g dose, 4x daily)
Protein Bound: Extensive
Metabolism: Hepatic oxidation/conjugation
Metabolites: 3'-hydroxymethyl and 3'-carboxyl acid metabolites and their glucuronic acid conjugates
Enzymes inhibited: Cyclooxygenase
Excretion: urine 66% (single dose); feces 20-25%
Dialyzable: No
Images
| BRAND | FORM. | UNIT PRICE | PILL IMAGE |
|---|---|---|---|
| mefenamic acid oral - | 250 mg capsule |  | |
| mefenamic acid oral - | 250 mg capsule |  | |
| mefenamic acid oral - | 250 mg capsule |  | |
| mefenamic acid oral - | 250 mg capsule |  |
Copyright © 2010 First DataBank, Inc.
Patient Handout
mefenamic acid oral
MEFENAMIC ACID - ORAL
(MEF-e-NAM-ik AS-id)
COMMON BRAND NAME(S): Ponstel
WARNING: Nonsteroidal anti-inflammatory drugs (including mefenamic acid) may rarely increase the risk of a heart attack or stroke. This effect can happen at any time while taking this drug but is more likely if you take it for a long time. The risk may be greater in older adults or if you have heart disease or increased risk for heart disease (for example, due to smoking, family history of heart disease, or conditions such as high blood pressure or diabetes). Do not take this drug right before or after heart bypass surgery (CABG).Also, this drug may rarely cause serious (rarely fatal) bleeding from the stomach or intestines. This effect can occur without warning symptoms at any time while taking this drug. Older adults may be at higher risk for this effect.Stop taking mefenamic acid and get medical help right away if you notice any of these rare but serious side effects: stomach/abdominal pain that doesn't go away, black/tarry stools, vomit that looks like coffee grounds, chest/jaw/left arm pain, shortness of breath, unusual sweating, confusion, weakness on one side of the body, trouble speaking, sudden vision changes.Talk to your doctor or pharmacist about the benefits and risks of taking this drug.
USES: See also Warning section.Mefenamic acid is used for the short-term relief of mild to moderate pain from various conditions such as headache, dental pain, menstrual cramps, and muscle aches.Mefenamic acid is known as a nonsteroidal anti-inflammatory drug (NSAID). It works by blocking your body's production of certain natural substances that cause inflammation. This effect helps to decrease swelling, pain, or fever.
HOW TO USE: Read the Medication Guide provided by your pharmacist before you start taking mefenamic acid and each time you get a refill. If you have any questions, ask your doctor or pharmacist.Take this medication by mouth as directed by your doctor, usually 4 times a day. Take this medication with a full glass of water (8 ounces/240 milliliters) unless your doctor directs you otherwise. Do not lie down for at least 10 minutes after taking this medication. If stomach upset occurs while taking this medication, take it with food or milk. Do not take mefenamic acid with antacids unless directed by your doctor. Certain antacids may change the amount of mefenamic acid absorbed by the body.The dosage and length of treatment are based on your medical condition and response to treatment. To reduce your risk of stomach bleeding and other side effects, take this medication at the lowest effective dose for the shortest possible time. Do not increase your dose or use this drug more often or for longer than prescribed. This medication usually should not be taken for more than 7 days at a time. Discuss the risks and benefits with your doctor or pharmacist.If you are taking this drug "as needed" (not on a regular schedule), remember that pain medications work best if they are used as the first signs of pain occur. If you wait until the pain has worsened, the medicine may not work as well.If you are using this medication for painful periods, take your first dose as soon as your period starts, or pain begins. Usually, you will only need to take it for the first 2 to 3 days of your period.Tell your doctor if your condition lasts or gets worse.
SIDE EFFECTS: See also Warning section.Upset stomach, nausea, diarrhea, dizziness, drowsiness, or blurred vision may occur. If any of these effects last or get worse, tell your doctor or pharmacist promptly.Remember that this medication has been prescribed because your doctor has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects.This medication may raise your blood pressure. Check your blood pressure regularly and tell your doctor if the results are high.Tell your doctor right away if you have any serious side effects, including: headache that is severe or doesn't go away, hearing changes (such as ringing in the ears), mental/mood changes, easy bleeding/bruising, difficult/painful swallowing, symptoms of heart failure (such as swelling ankles/feet, unusual tiredness, unusual/sudden weight gain).Get medical help right away if you have any very serious side effects, including: signs of kidney problems (such as change in the amount of urine, pink/bloody urine), unexplained stiff neck.Mefenamic acid may rarely cause serious (possibly fatal) liver disease. Get medical help right away if you have any symptoms of liver damage, including: nausea/vomiting that doesn't stop, loss of appetite, stomach/abdominal pain, yellowing eyes/skin, dark urine.A very serious allergic reaction to this drug is rare. However, get medical help right away if you notice any symptoms of a serious allergic reaction, including: fever, swollen lymph nodes, rash, itching/swelling (especially of the face/tongue/throat), severe dizziness, trouble breathing.This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist.In the US -Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088 or at www.fda.gov/medwatch.In Canada - Call your doctor for medical advice about side effects. You may report side effects to Health Canada at 1-866-234-2345.
PRECAUTIONS: See also Warning section.Before taking mefenamic acid, tell your doctor or pharmacist if you are allergic to it; or to aspirin or other NSAIDs (such as ibuprofen, naproxen, celecoxib); or if you have any other allergies. This product may contain inactive ingredients, which can cause allergic reactions or other problems. Talk to your pharmacist for more details.Before using this medication, tell your doctor or pharmacist your medical history, especially of: asthma (including a history of worsening breathing after taking aspirin or other NSAIDs), bleeding/clotting problems, blood disorders (such as anemia), growths in the nose (nasal polyps), heart disease (such as previous heart attack), high blood fat levels (cholesterol/triglyceride), high blood pressure, liver disease, stroke, swelling (edema, fluid retention), stomach/intestinal/esophagus problems (such as bleeding, heartburn, ulcers).Kidney problems can sometimes occur with the use of NSAID medications, including mefenamic acid. Problems are more likely to occur if you are dehydrated, have heart failure or kidney disease, are an older adult, or if you take certain medications (see also Drug Interactions section). Drink plenty of fluids as directed by your doctor to prevent dehydration and tell your doctor right away if you have pink/bloody urine or any unusual change in the amount of urine.This drug may make you dizzy, drowsy, or cause blurred vision. Alcohol or marijuana (cannabis) can worsen these effects. Do not drive, use machinery, or do anything that needs alertness or clear vision until you can do it safely. Limit alcoholic beverages. Talk to your doctor if you are using marijuana (cannabis).This medicine may cause stomach bleeding. Daily use of alcohol and tobacco, especially when combined with this medicine, may increase your risk for stomach bleeding. Limit alcohol and stop smoking. Ask your doctor or pharmacist about how much alcohol you may safely drink.This medication may make you more sensitive to the sun. Limit your time in the sun. Avoid tanning booths and sunlamps. Use sunscreen and wear protective clothing when outdoors. Tell your doctor right away if you get sunburned or have skin blisters/redness.Before having surgery, tell your doctor or dentist about all the products you use (including prescription drugs, nonprescription drugs, and herbal products).Older adults may be at greater risk for stomach/intestinal bleeding, kidney problems, heart attack, and stroke while using this drug.Before using this medication, women of childbearing age should talk with their doctor(s) about the benefits and risks. Tell your doctor if you are pregnant or if you plan to become pregnant. This medication may harm an unborn baby and cause problems with normal labor/delivery. It is not recommended for use in pregnancy from 20 weeks until delivery. If your doctor decides that you need to use this medication between 20 and 30 weeks of pregnancy, you should use the lowest effective dose for the shortest possible time. You should not use this medication after 30 weeks of pregnancy.This drug passes into breast milk. Consult your doctor before breast-feeding.
DRUG INTERACTIONS: Drug interactions may change how your medications work or increase your risk for serious side effects. This document does not contain all possible drug interactions. Keep a list of all the products you use (including prescription/nonprescription drugs and herbal products) and share it with your doctor and pharmacist. Do not start, stop, or change the dosage of any medicines without your doctor's approval.Some products that may interact with this drug are: aliskiren, ACE inhibitors (such as benazepril, lisinopril), angiotensin II receptor blockers (such as losartan, valsartan), cidofovir, corticosteroids (such as dexamethasone, prednisone), lithium, methotrexate, "water pills" (diuretics such as furosemide).This medication may increase the risk of bleeding when taken with other drugs that also may cause bleeding. Examples include anti-platelet drugs such as clopidogrel, "blood thinners" such as dabigatran/enoxaparin/warfarin, among others.Check all prescription and nonprescription medicine labels carefully since many medications contain pain relievers/fever reducers (aspirin, NSAIDs such as ibuprofen, ketorolac, naproxen). These drugs are similar to mefenamic acid and may increase your risk of side effects if taken together. However, if your doctor has directed you to take low-dose aspirin to prevent heart attack or stroke (usually 81-162 milligrams a day), you should keep taking the aspirin unless your doctor instructs you otherwise. Ask your doctor or pharmacist for more details.This medication may interfere with certain lab tests (such as urine bile test), possibly causing false test results. Make sure lab personnel and all your doctors know you use this drug.
OVERDOSE: If someone has overdosed and has serious symptoms such as passing out or trouble breathing, call 911. Otherwise, call a poison control center right away. US residents can call their local poison control center at 1-800-222-1222. Canada residents can call a provincial poison control center. Symptoms of overdose may include: severe stomach pain, slow/shallow breathing, extreme drowsiness.
NOTES: Do not share this medication with others.Lab and/or medical tests (such as complete blood count, liver/kidney function, blood pressure) may be done while you are using this medication. Keep all medical and lab appointments. Consult your doctor for more details.
MISSED DOSE: If you are taking this drug on a regular schedule (not just "as needed") and you miss a dose, take it as soon as you remember. If it is near the time of the next dose, skip the missed dose. Take your next dose at the regular time. Do not double the dose to catch up.
STORAGE: Store at room temperature in a tightly closed container away from light and moisture. Do not store in the bathroom. Keep all medications away from children and pets.Do not flush medications down the toilet or pour them into a drain unless instructed to do so. Properly discard this product when it is expired or no longer needed. Consult your pharmacist or local waste disposal company.
Information last revised June 2022. Copyright(c) 2023 First Databank, Inc.
IMPORTANT: HOW TO USE THIS INFORMATION: This is a summary and does NOT have all possible information about this product. This information does not assure that this product is safe, effective, or appropriate for you. This information is not individual medical advice and does not substitute for the advice of your health care professional. Always ask your health care professional for complete information about this product and your specific health needs.
Formulary
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