An inhibitor of DOPA decarboxylase, preventing conversion of levodopa to dopamine. It is used in parkinson disease to reduce peripheral adverse effects of levodopa. It has no antiparkinson actions by itself. .

HMD - Pharmacology:

When mixed with levodopa, carbidopa inhibits the peripheral conversion of levodopa to dopamine and the decarboxylation of oxitriptan to serotonin by aromatic L-amino acid decarboxylase. This results in increased amount of levodopa and oxitriptan available for transport to the CNS. HMD also inhibits the metabolism of levodopa in the GI tract, thus, increasing the bioavailability of levodopa.

HMD for patients

HMD is used with levodopa to treat Parkinsons disease. Parkinsons disease
is believed to be related to low levels of a chemical called dopamine (DOE pa meen)
in the brain. Levodopa (Dopar, Larodopa) is turned into dopamine in the body.
HMD is used with levodopa to prevent the breakdown (metabolism) of levodopa
before it can reach the brain and take effect. HMD is only effective if it is
taken with levodopa. It has no effect if it is used alone. HMD is used with
levodopa to treat the stiffness, tremors, spasms, and poor muscle control of
Parkinsons disease. These medications are also used to treat the same muscular
conditions when they are caused by drugs such as chlorpromazine (Thorazine),
fluphenazine (Prolixin), perphenazine (Trilafon), and others.

HMD Interactions

Caution should be exercised when the following drugs are administered concomitantly with LODOSYN (HMD) given with levodopa or carbidopa-levodopa combination products.

Symptomatic postural hypotension has occurred when LODOSYN, given with levodopa or carbidopa-levodopa combination products, was added to the treatment of a patient receiving antihypertensive drugs. Therefore, when therapy with LODOSYN, given with or without levodopa or carbidopa-levodopa combination products, is started, dosage adjustment of the antihypertensive drug may be required.

For patients receiving monoamine oxidase inhibitors, see CONTRAINDICATIONS. Concomitant therapy with selegiline and carbidopa-levodopa may be associated with severe orthostatic hypotension not attributable to carbidopa-levodopa alone.

There have been rare reports of adverse reactions, including hypertension and dyskinesia, resulting from the concomitant use of tricyclic antidepressants and carbidopa-levodopa preparations.

Dopamine D2 receptor antagonists (e.g., phenothiazines, butyrophenones, risperidone) and isoniazid may reduce the therapeutic effects of levodopa. In addition, the beneficial effects of levodopa in Parkinsons disease have been reported to be reversed by phenytoin and papaverine. Patients taking these drugs with LODOSYN and levodopa or carbidopa-levodopa combination products should be carefully observed for loss of therapeutic response.

Iron salts may reduce the bioavailability of carbidopa and levodopa. The clinical relevance is unclear.

Although metoclopramide may increase the bioavailability of levodopa by increasing gastric emptying, metoclopramide may also adversely affect disease control by its dopamine receptor antagonistic properties.

HMD Contraindications

LODOSYN is contraindicated in patients with known hypersensitivity to any component of this drug.

Nonselective monoamine oxidase (MAO) inhibitors are contraindicated for use with levodopa or carbidopa-levodopa combination products with or without LODOSYN. These inhibitors must be discontinued at least two weeks prior to initiating therapy with levodopa. SINEMET (HMD-Levodopa), or levodopa may be administered concomitantly with the manufacturers recommended dose of an MAO inhibitor with selectivity for MAO type B (e.g., selegiline HCl).

Levodopa or carbidopa-levodopa products, with or without LODOSYN, are contraindicated in patients with narrow-angle glaucoma.

Because levodopa or carbidopa-levodopa products, with or without LODOSYN, may activate a malignant melanoma, they should not be used in patients with suspicious, undiagnosed skin lesions or a history of melanoma.

Generic name, Overdose, Half Life HMD, Food Interactions, Chemical, etc..

HMD see also Saw Palmetto

Brand Names containing Carbidopa
General health

Chemical structure:
O O N O N O H H H H H H H H H H H H H H C10H14N2O4 2D chemical structure C10H14N2O4 SVG | 2D structure Carbidopa | Porphobilinogen | chemical names, chemical properties, classification C10H14N2O4