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Carbidopa (Levodopa)

 

Carbidopa / Levodopa (generic Sinemet) Review

brand name: Sinemet
generic names: Levodopa, Carbidopa, carbidopa

How does it work?

Sinemet CR and Half Sinemet CR tablets contain the active ingredients levodopa and carbidopa. This combination of medicines is also sometimes known as co-careldopa. It is used in Parkinson’s disease to increase the levels of dopamine in the brain.

Dopamine is a substance known as a neurotransmitter. Neurotransmitters are found the brain and nervous system and are involved in transmitting messages between nerves. These messages allow the normal functioning of the body. The neurotransmitter dopamine is known to be reduced or absent in the brains of people with Parkinson's disease, and this is thought to be the cause of the disease symptoms.

When you take levodopa, it is converted into dopamine in the brain. This replaces the lost dopamine and therefore reduces some of the symptoms of the disease.

Levodopa is also converted into dopamine in the rest of the body, which can cause unwanted side effects such as nausea and palpitations. Carbidopa is used in combination with the levodopa to prevent this happening. Carbidopa is a type of medicine called a dopa-decarboxylase inhibitor. It blocks the conversion of levodopa to dopamine in the body and so prevents these side effects. (Carbidopa cannot pass into the brain and so does not affect the conversion of levodopa to dopamine in the brain.)

The combination of levodopa and carbidopa is therefore effective in the treatment of Parkinson's disease, while minimising the side effects caused by levodopa on the rest of the body.

Sinemet CR and Half Sinemet CR tablets are modified release tablets. They are designed to release the medicine slowly and continuously over several hours to help provide steady blood levels of the medicine throughout the day. These tablets must be swallowed whole and not broken chewed or crushed, to avoid damaging the modified release action.

What should I discuss with my healthcare provider before taking carbidopa and levodopa?

If you are already taking levodopa (Larodopa, Dopar), you will have to stop taking it at least 12 hours before you take your first dose of carbidopa and levodopa.

Do not take carbidopa and levodopa if you are taking or have taken a monoamine oxidase inhibitor (MAOI) such as phenelzine (Nardil), isocarboxazid (Marplan), or tranylcypromine (Parnate) in the past 14 days.

You may not be able to take carbidopa and levodopa, or you may need a lower dose or special monitoring during treatment if you have any of the conditions listed above.

Do not take this medication if you have

• current or past history of malignant melanoma (a type of skin cancer).
• narrow-angle glaucoma (angle closure glaucoma), or

Before taking this medication, tell your doctor if you have:

• depression or any other psychiatric disorder.
• wide-angle glaucoma; or
• a stomach or intestinal ulcer;
• an endocrine (hormonal) disease;
• kidney disease;
• liver disease;
• respiratory disease, including asthma and chronic obstructive pulmonary disease (COPD);
• any kind of heart disease, a previous heart attack, arteriosclerosis (hardening of the arteries), including high blood pressure, or an irregular heartbeat;

Parcopa 10/100 mg and 25/100 mg tablets each contain 3.4 mg of phenylalanine; Parcopa 25/250 mg tablet contains 8.4 mg of phenylalanine. Talk to your doctor if you have phenylketonuria or have a family history of phenylketonuria.

Carbidopa and levodopa is in the FDA pregnancy category C. This means that it is not known whether carbidopa and levodopa will harm an unborn baby. Do not take carbidopa and levodopa without first talking to your doctor if you are pregnant. It is also not known whether carbidopa and levodopa will harm a nursing infant. Do not take carbidopa and levodopa without first talking to your doctor if you are breast-feeding a baby.

Where can I keep my medicine?

Keep out of the reach of children in a container that small children cannot open.

Store at room temperature between 15° and 30°C (59° and 86°F). Protect from light. Keep container tightly closed. Throw away any unused medicine after the expiration date.

Label warnings

• This medication may cause your urine to be coloured reddish.
  
  
• This medication should be swallowed whole, not chewed.
  
  

Why should Sinemet (Carbidopa) CR not be prescribed?

Do not take Sinemet (Carbidopa) CR if you are sensitive to or have ever had an allergic reaction to its ingredients.

Sinemet (Carbidopa) CR should not be prescribed if you have a suspicious, undiagnosed mole or a history of melanoma.

What if I miss a dose?

If you miss a dose, take it as soon as you can. If it is less than 2 hours to your next dose, take only that dose. Do not take double or extra doses. Try not to miss a dose.