Dosing & Uses
Dosage Forms & Strengths
(tablet)
- 25 mg
Parkinson's Disease
For use with carbidopa-levodopa or with levodopa for Parkinson's disease in patients for whom the dosage of carbidopa-levodopa combo provides less than adequate daily dosage of carbidopa, or in patients whose dosage requirement of carbidopa & levodopa necessitates separate titration of each entity
Dosage dependent upon concurrent dose of carbidopa-levodopa or levodopa & patient's specific needs
Patients taking Sinemet 10/100: Administer 25 mg carbidopa daily with first daily dose of Sinemet 10/100 if necessary; may administer 12.5-25 mg carbidopa with each subsequent dose of Sinemet 10/100; not to exceed 200 mg carbidopa/day including carbidopa from Sinemet
Patients taking Sinemet 25/250 or 25/100: Administer 25 mg carbidopa daily with either Sinemet strength throughout the day; not to exceed 200 mg/day of carbidopa including the Sinemet combination
Titration of carbidpa and levodopa (individually)
- Administer 25 mg carbidopa PO q6-8hr concurrently with levodopa; administer 20-25% less than the previous levodopa in carbidopa naive patients; first dose of carbidopa should be taken ≤12hr after the test dose of levodopa in carbidopa naive patients; increase or decrease dose by 1/2 or 1 tab/day
Safety & efficacy in children not established
Interactions
Interaction Checker
No Results

Contraindicated
Serious - Use Alternative
Significant - Monitor Closely
Minor

Contraindicated (0)
Serious - Use Alternative (0)
Monitor Closely (68)
- acebutolol
carbidopa increases effects of acebutolol by pharmacodynamic synergism. Use Caution/Monitor. Therapy with carbidopa, given with or without levodopa or carbidopa-levodopa combination products, is started, dosage adjustment of the antihypertensive drug may be required.
- alfuzosin
carbidopa increases effects of alfuzosin by pharmacodynamic synergism. Use Caution/Monitor. Monitor for hypotension.
- amiloride
carbidopa increases effects of amiloride by pharmacodynamic synergism. Use Caution/Monitor. Therapy with carbidopa, given with or without levodopa or carbidopa-levodopa combination products, is started, dosage adjustment of the antihypertensive drug may be required.
- amlodipine
carbidopa increases effects of amlodipine by pharmacodynamic synergism. Use Caution/Monitor. Therapy with carbidopa, given with or without levodopa or carbidopa-levodopa combination products, is started, dosage adjustment of the antihypertensive drug may be required.
- asenapine
carbidopa increases effects of asenapine by pharmacodynamic synergism. Use Caution/Monitor. Monitor for hypotension.
- atenolol
carbidopa increases effects of atenolol by pharmacodynamic synergism. Use Caution/Monitor. Therapy with carbidopa, given with or without levodopa or carbidopa-levodopa combination products, is started, dosage adjustment of the antihypertensive drug may be required.
- benazepril
carbidopa increases effects of benazepril by pharmacodynamic synergism. Use Caution/Monitor. Therapy with carbidopa, given with or without levodopa or carbidopa-levodopa combination products, is started, dosage adjustment of the antihypertensive drug may be required.
- betaxolol
carbidopa increases effects of betaxolol by pharmacodynamic synergism. Use Caution/Monitor. Therapy with carbidopa, given with or without levodopa or carbidopa-levodopa combination products, is started, dosage adjustment of the antihypertensive drug may be required.
- bisoprolol
carbidopa increases effects of bisoprolol by pharmacodynamic synergism. Use Caution/Monitor. Therapy with carbidopa, given with or without levodopa or carbidopa-levodopa combination products, is started, dosage adjustment of the antihypertensive drug may be required.
- bosentan
carbidopa increases effects of bosentan by pharmacodynamic synergism. Use Caution/Monitor. Therapy with carbidopa, given with or without levodopa or carbidopa-levodopa combination products, is started, dosage adjustment of the antihypertensive drug may be required.
- bumetanide
carbidopa increases effects of bumetanide by pharmacodynamic synergism. Use Caution/Monitor. Therapy with carbidopa, given with or without levodopa or carbidopa-levodopa combination products, is started, dosage adjustment of the antihypertensive drug may be required.
- captopril
carbidopa increases effects of captopril by pharmacodynamic synergism. Use Caution/Monitor. Therapy with carbidopa, given with or without levodopa or carbidopa-levodopa combination products, is started, dosage adjustment of the antihypertensive drug may be required.
- carvedilol
carbidopa increases effects of carvedilol by pharmacodynamic synergism. Use Caution/Monitor. Therapy with carbidopa, given with or without levodopa or carbidopa-levodopa combination products, is started, dosage adjustment of the antihypertensive drug may be required.
- chlorothiazide
carbidopa increases effects of chlorothiazide by pharmacodynamic synergism. Use Caution/Monitor. Therapy with carbidopa, given with or without levodopa or carbidopa-levodopa combination products, is started, dosage adjustment of the antihypertensive drug may be required.
- chlorthalidone
carbidopa increases effects of chlorthalidone by pharmacodynamic synergism. Use Caution/Monitor. Therapy with carbidopa, given with or without levodopa or carbidopa-levodopa combination products, is started, dosage adjustment of the antihypertensive drug may be required.
- clevidipine
carbidopa increases effects of clevidipine by pharmacodynamic synergism. Use Caution/Monitor. Therapy with carbidopa, given with or without levodopa or carbidopa-levodopa combination products, is started, dosage adjustment of the antihypertensive drug may be required.
- clonidine
carbidopa increases effects of clonidine by pharmacodynamic synergism. Use Caution/Monitor. Therapy with carbidopa, given with or without levodopa or carbidopa-levodopa combination products, is started, dosage adjustment of the antihypertensive drug may be required.
- doxazosin
carbidopa increases effects of doxazosin by pharmacodynamic synergism. Use Caution/Monitor. Therapy with carbidopa, given with or without levodopa or carbidopa-levodopa combination products, is started, dosage adjustment of the antihypertensive drug may be required.
- droxidopa
carbidopa decreases effects of droxidopa by decreasing metabolism. Use Caution/Monitor. Carbidopa, a peripheral dopa-decarboxylase inhibitor, could prevent the conversion of droxidopa to norepinephrine; increased droxidopa dose may be required.
- enalapril
carbidopa increases effects of enalapril by pharmacodynamic synergism. Use Caution/Monitor. Therapy with carbidopa, given with or without levodopa or carbidopa-levodopa combination products, is started, dosage adjustment of the antihypertensive drug may be required.
- eplerenone
carbidopa increases effects of eplerenone by pharmacodynamic synergism. Use Caution/Monitor. Therapy with carbidopa, given with or without levodopa or carbidopa-levodopa combination products, is started, dosage adjustment of the antihypertensive drug may be required.
- epoprostenol
carbidopa increases effects of epoprostenol by pharmacodynamic synergism. Use Caution/Monitor. Therapy with carbidopa, given with or without levodopa or carbidopa-levodopa combination products, is started, dosage adjustment of the antihypertensive drug may be required.
- esmolol
carbidopa increases effects of esmolol by pharmacodynamic synergism. Use Caution/Monitor. Therapy with carbidopa, given with or without levodopa or carbidopa-levodopa combination products, is started, dosage adjustment of the antihypertensive drug may be required.
- ethacrynic acid
carbidopa increases effects of ethacrynic acid by pharmacodynamic synergism. Use Caution/Monitor. Therapy with carbidopa, given with or without levodopa or carbidopa-levodopa combination products, is started, dosage adjustment of the antihypertensive drug may be required.
- felodipine
carbidopa increases effects of felodipine by pharmacodynamic synergism. Use Caution/Monitor. Therapy with carbidopa, given with or without levodopa or carbidopa-levodopa combination products, is started, dosage adjustment of the antihypertensive drug may be required.
- fenoldopam
carbidopa increases effects of fenoldopam by pharmacodynamic synergism. Use Caution/Monitor. Therapy with carbidopa, given with or without levodopa or carbidopa-levodopa combination products, is started, dosage adjustment of the antihypertensive drug may be required.
- fosinopril
carbidopa increases effects of fosinopril by pharmacodynamic synergism. Use Caution/Monitor. Therapy with carbidopa, given with or without levodopa or carbidopa-levodopa combination products, is started, dosage adjustment of the antihypertensive drug may be required.
- furosemide
carbidopa increases effects of furosemide by pharmacodynamic synergism. Use Caution/Monitor. Therapy with carbidopa, given with or without levodopa or carbidopa-levodopa combination products, is started, dosage adjustment of the antihypertensive drug may be required.
- guanfacine
carbidopa increases effects of guanfacine by pharmacodynamic synergism. Use Caution/Monitor. Therapy with carbidopa, given with or without levodopa or carbidopa-levodopa combination products, is started, dosage adjustment of the antihypertensive drug may be required.
- hydralazine
carbidopa increases effects of hydralazine by pharmacodynamic synergism. Use Caution/Monitor. Therapy with carbidopa, given with or without levodopa or carbidopa-levodopa combination products, is started, dosage adjustment of the antihypertensive drug may be required.
- hydrochlorothiazide
carbidopa increases effects of hydrochlorothiazide by pharmacodynamic synergism. Use Caution/Monitor. Therapy with carbidopa, given with or without levodopa or carbidopa-levodopa combination products, is started, dosage adjustment of the antihypertensive drug may be required.
- iloprost
carbidopa increases effects of iloprost by pharmacodynamic synergism. Use Caution/Monitor. Therapy with carbidopa, given with or without levodopa or carbidopa-levodopa combination products, is started, dosage adjustment of the antihypertensive drug may be required.
- indapamide
carbidopa increases effects of indapamide by pharmacodynamic synergism. Use Caution/Monitor. Therapy with carbidopa, given with or without levodopa or carbidopa-levodopa combination products, is started, dosage adjustment of the antihypertensive drug may be required.
- irbesartan
carbidopa increases effects of irbesartan by pharmacodynamic synergism. Use Caution/Monitor. Therapy with carbidopa, given with or without levodopa or carbidopa-levodopa combination products, is started, dosage adjustment of the antihypertensive drug may be required.
- isradipine
carbidopa increases effects of isradipine by pharmacodynamic synergism. Use Caution/Monitor. Therapy with carbidopa, given with or without levodopa or carbidopa-levodopa combination products, is started, dosage adjustment of the antihypertensive drug may be required.
- labetalol
carbidopa increases effects of labetalol by pharmacodynamic synergism. Use Caution/Monitor. Therapy with carbidopa, given with or without levodopa or carbidopa-levodopa combination products, is started, dosage adjustment of the antihypertensive drug may be required.
- lisinopril
carbidopa increases effects of lisinopril by pharmacodynamic synergism. Use Caution/Monitor. Therapy with carbidopa, given with or without levodopa or carbidopa-levodopa combination products, is started, dosage adjustment of the antihypertensive drug may be required.
- methyclothiazide
carbidopa increases effects of methyclothiazide by pharmacodynamic synergism. Use Caution/Monitor. Consider decreasing dosage of antihypertensive agent.
- metolazone
carbidopa increases effects of metolazone by pharmacodynamic synergism. Use Caution/Monitor. Therapy with carbidopa, given with or without levodopa or carbidopa-levodopa combination products, is started, dosage adjustment of the antihypertensive drug may be required.
- metoprolol
carbidopa increases effects of metoprolol by pharmacodynamic synergism. Use Caution/Monitor. Therapy with carbidopa, given with or without levodopa or carbidopa-levodopa combination products, is started, dosage adjustment of the antihypertensive drug may be required.
- metyrosine
carbidopa increases effects of metyrosine by pharmacodynamic synergism. Use Caution/Monitor. Monitor for hypotension.
- minoxidil
carbidopa increases effects of minoxidil by pharmacodynamic synergism. Use Caution/Monitor. Therapy with carbidopa, given with or without levodopa or carbidopa-levodopa combination products, is started, dosage adjustment of the antihypertensive drug may be required.
- moexipril
carbidopa increases effects of moexipril by pharmacodynamic synergism. Use Caution/Monitor. Therapy with carbidopa, given with or without levodopa or carbidopa-levodopa combination products, is started, dosage adjustment of the antihypertensive drug may be required.
- nadolol
carbidopa increases effects of nadolol by pharmacodynamic synergism. Use Caution/Monitor. Therapy with carbidopa, given with or without levodopa or carbidopa-levodopa combination products, is started, dosage adjustment of the antihypertensive drug may be required.
- nebivolol
carbidopa increases effects of nebivolol by pharmacodynamic synergism. Use Caution/Monitor. Therapy with carbidopa, given with or without levodopa or carbidopa-levodopa combination products, is started, dosage adjustment of the antihypertensive drug may be required.
- nicardipine
carbidopa increases effects of nicardipine by pharmacodynamic synergism. Use Caution/Monitor. Therapy with carbidopa, given with or without levodopa or carbidopa-levodopa combination products, is started, dosage adjustment of the antihypertensive drug may be required.
- nifedipine
carbidopa increases effects of nifedipine by pharmacodynamic synergism. Use Caution/Monitor. Therapy with carbidopa, given with or without levodopa or carbidopa-levodopa combination products, is started, dosage adjustment of the antihypertensive drug may be required.
- nisoldipine
carbidopa increases effects of nisoldipine by pharmacodynamic synergism. Use Caution/Monitor. Therapy with carbidopa, given with or without levodopa or carbidopa-levodopa combination products, is started, dosage adjustment of the antihypertensive drug may be required.
- penbutolol
carbidopa increases effects of penbutolol by pharmacodynamic synergism. Use Caution/Monitor. Therapy with carbidopa, given with or without levodopa or carbidopa-levodopa combination products, is started, dosage adjustment of the antihypertensive drug may be required.
- perindopril
carbidopa increases effects of perindopril by pharmacodynamic synergism. Use Caution/Monitor. Therapy with carbidopa, given with or without levodopa or carbidopa-levodopa combination products, is started, dosage adjustment of the antihypertensive drug may be required.
- phenoxybenzamine
carbidopa increases effects of phenoxybenzamine by pharmacodynamic synergism. Use Caution/Monitor. Consider decreasing dosage of antihypertensive agent.
- phentolamine
carbidopa increases effects of phentolamine by pharmacodynamic synergism. Use Caution/Monitor. Monitor for hypotension.
- pindolol
carbidopa increases effects of pindolol by pharmacodynamic synergism. Use Caution/Monitor. Therapy with carbidopa, given with or without levodopa or carbidopa-levodopa combination products, is started, dosage adjustment of the antihypertensive drug may be required.
- prazosin
carbidopa increases effects of prazosin by pharmacodynamic synergism. Use Caution/Monitor. Therapy with carbidopa, given with or without levodopa or carbidopa-levodopa combination products, is started, dosage adjustment of the antihypertensive drug may be required.
- propranolol
carbidopa increases effects of propranolol by pharmacodynamic synergism. Use Caution/Monitor. Therapy with carbidopa, given with or without levodopa or carbidopa-levodopa combination products, is started, dosage adjustment of the antihypertensive drug may be required.
- quinapril
carbidopa increases effects of quinapril by pharmacodynamic synergism. Use Caution/Monitor. Therapy with carbidopa, given with or without levodopa or carbidopa-levodopa combination products, is started, dosage adjustment of the antihypertensive drug may be required.
- ramipril
carbidopa increases effects of ramipril by pharmacodynamic synergism. Use Caution/Monitor. Therapy with carbidopa, given with or without levodopa or carbidopa-levodopa combination products, is started, dosage adjustment of the antihypertensive drug may be required.
- sacubitril/valsartan
carbidopa increases effects of sacubitril/valsartan by pharmacodynamic synergism. Use Caution/Monitor. Consider decreasing dosage of antihypertensive agent.
- silodosin
carbidopa increases effects of silodosin by pharmacodynamic synergism. Use Caution/Monitor. Monitor for hypotension.
- sotalol
carbidopa increases effects of sotalol by pharmacodynamic synergism. Use Caution/Monitor. Therapy with carbidopa, given with or without levodopa or carbidopa-levodopa combination products, is started, dosage adjustment of the antihypertensive drug may be required.
- spironolactone
carbidopa increases effects of spironolactone by pharmacodynamic synergism. Use Caution/Monitor. Therapy with carbidopa, given with or without levodopa or carbidopa-levodopa combination products, is started, dosage adjustment of the antihypertensive drug may be required.
- terazosin
carbidopa increases effects of terazosin by pharmacodynamic synergism. Use Caution/Monitor. Therapy with carbidopa, given with or without levodopa or carbidopa-levodopa combination products, is started, dosage adjustment of the antihypertensive drug may be required.
- timolol
carbidopa increases effects of timolol by pharmacodynamic synergism. Use Caution/Monitor. Therapy with carbidopa, given with or without levodopa or carbidopa-levodopa combination products, is started, dosage adjustment of the antihypertensive drug may be required.
- torsemide
carbidopa increases effects of torsemide by pharmacodynamic synergism. Use Caution/Monitor. Therapy with carbidopa, given with or without levodopa or carbidopa-levodopa combination products, is started, dosage adjustment of the antihypertensive drug may be required.
- trandolapril
carbidopa increases effects of trandolapril by pharmacodynamic synergism. Use Caution/Monitor. Therapy with carbidopa, given with or without levodopa or carbidopa-levodopa combination products, is started, dosage adjustment of the antihypertensive drug may be required.
- treprostinil
carbidopa increases effects of treprostinil by pharmacodynamic synergism. Use Caution/Monitor. Therapy with carbidopa, given with or without levodopa or carbidopa-levodopa combination products, is started, dosage adjustment of the antihypertensive drug may be required.
- triamterene
carbidopa increases effects of triamterene by pharmacodynamic synergism. Use Caution/Monitor. Therapy with carbidopa, given with or without levodopa or carbidopa-levodopa combination products, is started, dosage adjustment of the antihypertensive drug may be required.
- verapamil
carbidopa increases effects of verapamil by pharmacodynamic synergism. Use Caution/Monitor. Therapy with carbidopa, given with or without levodopa or carbidopa-levodopa combination products, is started, dosage adjustment of the antihypertensive drug may be required.
Minor (6)
- ferric maltol
ferric maltol decreases levels of carbidopa by inhibition of GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown.
- ferrous fumarate
ferrous fumarate decreases levels of carbidopa by inhibition of GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown.
- ferrous gluconate
ferrous gluconate decreases levels of carbidopa by inhibition of GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown.
- ferrous sulfate
ferrous sulfate decreases levels of carbidopa by inhibition of GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown.
- iron dextran complex
iron dextran complex decreases levels of carbidopa by inhibition of GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown.
- polysaccharide iron
polysaccharide iron decreases levels of carbidopa by inhibition of GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown.
Warnings
Contraindications
Narrow-angle glaucoma
Within 14 days of taking a nonselective MAO inhibitor (may be administered concomitantly with manufacturer’s recommended dose of an MAO inhibitor with selectivity for MAO type B (eg, selegiline HCl)
Cautions
When this drug is to be given to carbidopa-naive patients who are being treated with levodopa alone, the two drugs should be given at the same time
As with levodopa alone, periodic evaluations of hepatic, hematopoietic, cardiovascular, and renal function are recommended during extended concomitant therapy with carbidopa and levodopa, or with carbidopa and carbidopa-levodopa or any combination of these drugs
At least twelve hours should elapse between the last dose of levodopa and initiation of therapy with carbidopa and levodopa in combination; start with no more than one-fifth (20%) to one-fourth (25%) of previous daily dosage of levodopa when given without carbidopa
The addition of carbidopa with levodopa or carbidopa-levodopa reduces the peripheral effects (nausea, vomiting) due to decarboxylation of levodopa; however, carbidopa does not decrease adverse reactions due to central effects of levodopa
Because carbidopa permits more levodopa to reach the brain and more dopamine to be formed, certain adverse central nervous system (CNS) effects, eg, dyskinesias (involuntary movements), may occur at lower dosages and sooner with levodopa in combination with carbidopa than with levodopa alone
Carbidopa may potentiate the dopaminergic side effects of levodopa and may cause or exacerbate preexisting dyskinesia
Patients treated with carbidopa and carbidopa-levodopa should be observed carefully for the development of depression with concomitant suicidal tendencies
Somnolence
- Patients taking carbidopa-levodopa products alone or with other dopaminergic drugs have reported suddenly falling asleep without prior warning of sleepiness while engaged in activities of daily living (includes operation of motor vehicles); some of these episodes resulted in automobile accidents
- Although many patients reported somnolence while on dopaminergic medications, some did perceive that they had no warning signs, such as excessive drowsiness, and believed that they were alert immediately prior to the event
- Some patients reported these events one year after initiation of treatment; falling asleep while engaged in activities of daily living usually occurs in patients experiencing pre-existing somnolence, although some patients may not give such a history; for this reason, prescribers should continually reassess patients for drowsiness or sleepiness especially since some of the events occur after the start of treatment
- Prescribers should be aware that patients may not acknowledge drowsiness or sleepiness until directly questioned about drowsiness or sleepiness during specific activities; patients who have already experienced somnolence or an episode of sudden sleep onset should not participate in these activities during treatment when taking carbidopa with other carbidopa-levodopa products
- Before initiating treatment with carbidopa, advise patients about potential to develop drowsiness and ask specifically about factors that may increase risk for somnolence with carbidopa such as the use of concomitant sedating medications and the presence of sleep disorders
- Consider discontinuing carbidopa in patients who report significant daytime sleepiness or episodes of falling asleep during activities that require active participation (eg, conversations, eating, etc); if treatment with this medication continues, patients should be advised not to drive and to avoid other potentially dangerous activities that might result in harm if the patient become somnolent; there is insufficient information to establish that dose reduction will eliminate episodes of falling asleep while engaged in activities of daily living
Hyperpyrexia and confusion
- Sporadic cases of a symptom complex resembling neuroleptic malignant syndrome (NMS) have been reported in association with dose reductions or withdrawal of certain antiparkinsonian agents such as levodopa, carbidopa-levodopa, or carbidopa-levodopa extended-release
- Patients should be observed carefully when the dosage of levodopa or carbidopa levodopa is reduced abruptly or discontinued, especially if patient is receiving neuroleptics
- NMS is an uncommon but life-threatening syndrome characterized by fever or hyperthermia; neurological findings, including muscle rigidity, involuntary movements, altered consciousness, mental status changes; other disturbances, such as autonomic dysfunction, tachycardia, tachypnea, sweating, hyper- or hypotension; laboratory findings, such as creatine phosphokinase elevation, leukocytosis, myoglobinuria, and increased serum myoglobin, reported
- Early diagnosis of this condition is important for the appropriate management of these patients; considering NMS as a possible diagnosis and ruling out other acute illnesses (eg, pneumonia, systemic infection, etc) is essential; this may be especially complex if the clinical presentation includes both serious medical illness and untreated or inadequately treated extrapyramidal signs and symptoms (EPS)
- Other important considerations in the differential diagnosis include central anticholinergic toxicity, heat stroke, drug fever, and primary central nervous system (CNS) pathology; management of NMS should include 1) intensive symptomatic treatment and medical monitoring and 2) treatment of any concomitant serious medical problems for which specific treatments are available
- Dopamine agonists, such as bromocriptine, and muscle relaxants, such as dantrolene, are often used in the treatment of NMS; however, their effectiveness has not been demonstrated in controlled studies
Impulse control
- Postmarketing reports suggest that patients treated with anti-Parkinson medications can experience intense urges to gamble, increased sexual urges, intense urges to spend money uncontrollably, binge eating, and other intense urges
- Patients may be unable to control these urges while taking one or more of the medications that are used for the treatment of Parkinson disease and that increase central dopaminergic tone, including carbidopa taken with levodopa and carbidopa
- In some cases, although not all, these urges were reported to have stopped when the dose of anti-Parkinson medications was reduced or discontinued; because patients may not recognize these behaviors as abnormal it is important for prescribers to specifically ask patients or their caregivers about the development of new or increased gambling urges, sexual urges, uncontrolled spending or other urges while being treated with this drug
- Physicians should consider dose reduction or stopping carbidopa or levodopa if a patient develops such urges while taking carbidopa with carbidopa/levodopa
Hallucinations/psychotic like behavior
- Hallucinations and psychotic-like behavior have been reported with dopaminergic medications; in general, hallucinations present shortly after the initiation of therapy and may be responsive to dose reduction in levodopa
- Hallucinations may be accompanied by confusion and, to a lesser extent, sleep disorder (insomnia) and excessive dreaming; carbidopa when taken with carbidopa-levodopa may have similar effects on thinking and behavior; this abnormal thinking and behavior may present with one or more symptoms, including paranoid ideation, delusions, hallucinations, confusion, psychotic-like behavior, disorientation, aggressive behavior, agitation, and delirium
- Ordinarily, patients with a major psychotic disorder should not be treated with carbidopa and carbidopa-levodopa, because of the risk of exacerbating psychosis; in addition, certain medications used to treat psychosis may exacerbate the symptoms of Parkinson’s disease and may decrease the effectiveness of carbidopa
Melanoma
- Epidemiological studies have shown that patients with Parkinson’s disease have a higher risk (2 to approximately 6-fold higher) of developing melanoma than general population; whether the observed increased risk was due to Parkinson disease or other factors, such as drugs used to treat Parkinson disease, is unclear
- Patients and providers are advised to monitor for melanomas frequently and on a regular basis when using this medication for Parkinson disease; ideally, periodic skin examinations should be performed by appropriately qualified individuals (eg, dermatologists)
Pregnancy & Lactation
Pregnancy
There are no adequate and well-controlled studies with carbidopa in pregnant women; it has been reported from individual cases that levodopa crosses the human placental barrier, enters the fetus, and is metabolized
Carbidopa concentrations in fetal tissue appeared to be minimal; carbidopa should be used during pregnancy only if potential benefit justifies potential risk to fetus
Animal data
- Carbidopa, at doses as high as 120 mg/kg/day, was without teratogenic effects in the mouse or rabbit; in the rabbit, but not in the mouse, carbidopa-levodopa produced visceral anomalies, similar to those seen with levodopa alone, at approximately 7 times the maximum recommended human dose; the teratogenic effect of levodopa in rabbits was unchanged by the concomitant administration of carbidopa
Lactation
It is not known whether carbidopa is excreted in human milk; because many drugs are excreted in human milk, and because of their potential for serious adverse reactions in nursing infants, a decision should be made whether to discontinue nursing or to discontinue the drug, taking into account the importance of the drug to the nursing woman
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 the aromatic amino-acid decarboxylase enzyme & conversion of levodopa to dopamine peripherally, which in turn reduces peripheral side-effects including nausea, vomiting, and cardiac arrhythmias; does not counter central effects of levodopa
Images
BRAND | FORM. | UNIT PRICE | PILL IMAGE |
---|---|---|---|
carbidopa oral - | 25 mg tablet | ![]() | |
carbidopa oral - | 25 mg tablet | ![]() | |
carbidopa oral - | 25 mg tablet | ![]() | |
carbidopa oral - | 25 mg tablet | ![]() | |
Lodosyn oral - | 25 mg tablet | ![]() |
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Patient Handout
carbidopa oral
CARBIDOPA - ORAL
(KAR-bi-DOE-pa)
COMMON BRAND NAME(S): Lodosyn
USES: This medication is used with a combination levodopa/carbidopa product to treat symptoms of Parkinson's disease or Parkinson-like symptoms (such as shakiness, stiffness, difficulty moving). Carbidopa must be taken together with a drug that contains levodopa to be effective. If used alone, carbidopa has no effect on Parkinson's symptoms. Parkinson's disease is thought to be caused by too little of a naturally occurring substance (dopamine) in the brain. Levodopa changes into dopamine in the brain, helping to control movement. Carbidopa prevents the breakdown of levodopa in the bloodstream so more levodopa can enter the brain. Carbidopa can also reduce some of levodopa's side effects such as nausea and vomiting.
HOW TO USE: Take this medication by mouth with or without food as directed by your doctor. You may be directed to take this medication with one, some, or all of your levodopa/carbidopa doses. Follow your doctor's instructions carefully. The dosage is based on your medical condition and response to treatment.Since this medication is always taken with a levodopa-containing product, it is best to avoid a high-protein diet (it decreases the amount of levodopa that your body takes in) during treatment, unless directed otherwise by your doctor. Separate your dose of this medication by as many hours as possible from any iron supplements or products containing iron (such as multivitamins with minerals) you may take. Iron can reduce the amount of levodopa absorbed by the body. Consult your doctor or pharmacist for more details.Use this medication regularly to get the most benefit from it. To help you remember, take it at the same time(s) each day.Some patients may experience a "wearing-off" (worsening of symptoms) before the next dose is due. An "on-off" effect might also occur, in which sudden short periods of stiffness occur. If these effects occur, contact your doctor for possible dose adjustments that may help to lessen this effect.Do not stop taking this medication and the levodopa-containing product without consulting your doctor. Some conditions may become worse when these drugs are quickly reduced or suddenly stopped. Your dose may need to be gradually reduced. (See also Side Effects section.)Tell your doctor if your condition does not improve or if it worsens.
SIDE EFFECTS: Side effects with carbidopa are rare and usually occur due to the levodopa-containing product that is taken together with it. The following side effects in this section may occur due to levodopa.Dizziness, lightheadedness, nausea, vomiting, loss of appetite, trouble sleeping, unusual dreams, or headache may occur. If any of these effects last or get worse, tell your doctor or pharmacist promptly.This medication (or levodopa) may cause saliva, urine, or sweat to turn a dark color. This effect is harmless, but your clothes may be stained.To reduce the risk of dizziness and lightheadedness, get up slowly when rising from a sitting or lying position.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.Some people taking this medication along with levodopa/carbidopa have fallen asleep suddenly during their usual daily activities (such as talking on the phone, driving). In some cases, sleep occurred without any feelings of drowsiness beforehand. This sleep effect may occur anytime during treatment with carbidopa and levodopa/carbidopa even if you have used these medications for a long time. If you experience increased sleepiness or fall asleep during the day, do not drive or do other possibly dangerous activities until you have discussed this effect with your doctor. Your risk of this sleep effect is increased by using alcohol or other medications that can make you drowsy. See also Precautions section.Tell your doctor right away if you have any serious side effects, including: new/worsening movements you can't control/spasms, greatly increased eye blinking/twitching, vision changes (such as blurred/double vision), eye pain, severe stomach/abdominal pain, black/tarry stools, vomit that looks like coffee grounds, mental/mood changes (such as agitation, hallucinations, depression, thoughts of suicide), signs of infection (such as sore throat that doesn't go away), easy bleeding/bruising, unusual tiredness, tingling of the hands/feet, unusual strong urges (such as increased gambling, increased sexual urges).Get medical help right away if you have any very serious side effects, including: chest pain, fainting.Abruptly stopping or reducing the dose of this medication and levodopa/carbidopa may rarely cause a serious condition called neuroleptic malignant syndrome (NMS). Get medical help right away if you have any of the following symptoms: fever, unusual muscle stiffness, severe confusion, sweating, fast/irregular heartbeat.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: 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: Before taking this medication, tell your doctor or pharmacist if you are allergic to it; or to foscarbidopa; 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: liver disease, glaucoma, breathing problems (such as asthma), heart disease (such as heart attack, irregular heartbeat), kidney disease, stomach/intestinal ulcer, mental/mood disorders (such as depression, schizophrenia), blood disorders, seizures, sleep disorder.This drug may make you dizzy or drowsy. Alcohol or marijuana (cannabis) can make you more dizzy or drowsy. Do not drive, use machinery, or do anything that needs alertness until you can do it safely. Limit alcoholic beverages. Talk to your doctor if you are using marijuana (cannabis). See also Side Effects section.Before having surgery, tell your doctor or dentist about all the products you use (including prescription drugs, nonprescription drugs, and herbal products).During pregnancy, this medication should be used only when clearly needed. Discuss the risks and benefits with your doctor.It is unknown if this medication passes into breast milk. Consult your doctor before breast-feeding.
DRUG INTERACTIONS: See also How to Use section.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 (or levodopa) include: certain drugs used to treat high blood pressure (such as methyldopa), tetrabenazine.Taking MAO inhibitors with this medication (along with a levodopa-containing product) may cause a serious (possibly fatal) drug interaction. Avoid taking MAO inhibitors (isocarboxazid, linezolid, metaxalone, methylene blue, moclobemide, phenelzine, procarbazine, tranylcypromine) during treatment with this medication. Most MAO inhibitors should also not be taken for two weeks before treatment with this medication. However, certain MAO inhibitors (rasagiline, safinamide, selegiline) may be used with careful monitoring by your doctor. Ask your doctor when to start or stop taking this medication.This medication (or levodopa) may interfere with certain lab tests (such as urine catecholamine/glucose/ketone tests), 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.
NOTES: Do not share this medication with others.Lab and/or medical tests (such as complete blood count, heart/kidney/liver function, blood pressure) should be done while you are taking this medication. Keep all medical and lab appointments. Consult your doctor for more details.
MISSED DOSE: If 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 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 November 2023. 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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