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
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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.
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
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Formulary
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