Carbidopa/Levodopa: Price, Dosage & Where to Buy

Carbidopa/levodopa is a combination medicine used primarily to treat Parkinson's disease and requires a prescription in the United Kingdom. It combines levodopa, an aromatic amino acid, with carbidopa, an aromatic amino acid decarboxylation inhibitor, to support dopamine activity in the brain. Treatment is adjusted according to clinical response and tolerability, with monitoring for unwanted effects.

Levodopa is converted into dopamine in the brain. Dopamine is a chemical messenger involved in controlling movement, and replacing its activity helps relieve the movement difficulties associated with Parkinson's disease. Carbidopa blocks an enzyme that would otherwise convert levodopa into dopamine outside the brain.

This allows more levodopa to reach the brain. The combination therefore supports dopamine activity where it is needed while limiting conversion elsewhere in the body.

Carbidopa/levodopa is indicated for Parkinson's disease and certain other forms of parkinsonism. Parkinsonism describes a pattern of movement difficulties associated with reduced dopamine activity, rather than a single cause.

The listed indications include post-encephalitic parkinsonism, which occurs after inflammation of the brain, and symptomatic parkinsonism that may follow carbon monoxide poisoning or manganese poisoning. Treatment is intended to control symptoms, with the response and unwanted effects guiding the prescriber's adjustments.

The label lists oral tablets and orally disintegrating tablets containing carbidopa/levodopa strengths of 10 mg/100 mg, 25 mg/100 mg and 25 mg/250 mg. The label lists extended-release tablets containing 25 mg/100 mg and 50 mg/200 mg, and extended-release capsules containing 23.75 mg/95 mg, 36.25 mg/145 mg, 48.75 mg/195 mg and 61.25 mg/245 mg. The usual starting dose is one DHIVY 25 mg/100 mg tablet three times a day.

The label lists increases of up to one whole tablet every day or every other day, to a maximum of eight whole DHIVY tablets daily. These starting and adjustment details refer specifically to DHIVY tablets, rather than every formulation. Treatment is individualised according to clinical response and tolerability, with close monitoring during adjustment.

The label advises vitamin B6 assessment before treatment and periodically during treatment. Sudden discontinuation or rapid dose reduction should be avoided.

The label specifies storage at 20°C to 25°C, with excursions permitted between 15°C to 30°C. Keep the tablets in a tightly closed container, protected from light and moisture. A light-resistant container is specified for dispensing.

A missed dose can interrupt symptom control. General pharmacy advice is to resume the prescribed schedule rather than double a dose to compensate.

Ask a pharmacist for advice if the timing is unclear or several doses have been missed. Sudden discontinuation or rapid dose reduction should be avoided because withdrawal can cause serious symptoms.

There are no adequate data on developmental risk in pregnant women. Animal studies indicate that carbidopa/levodopa may cause harm to the developing baby. Levodopa has been detected in human milk, but there are no data on carbidopa in milk or effects on the breastfed infant.

Milk production may be inhibited because levodopa reduces prolactin secretion. Discuss treatment and breastfeeding with a doctor, considering the mother's clinical need and potential effects on the infant.