Levodopa

Brand names

• Apo-Levocarb
• Bendopa
• Dopar
• Endo Levodopa / Carbidopa
• Larodopa
• Nu-Levocarb
• Prolopa [CD]
• Sinemet [CD]
• Sinemet CR [CD]

Usage

To treat Parkinson's disease and Parkinson-like syndromes, which can occur following injury to or infection of the central nervous system, damage to the blood vessels in the brain, or exposure to certain toxins. Levodopa/carbidopa improves or alleviates such symptoms as rigidity, slowness, loss of smoothness of movement, and tremor.

How it works

Levodopa/ carbidopa increases brain levels of dopamine, a chemical that plays an essential role in the smooth movement of muscles.

Side effects

Serious

Nausea, fatigue, depression, dizziness or lightheadedness when standing or sitting up suddenly (orthostatic hypotension), fainting or near fainting.

Common

With long-term use, quirky involuntary muscle movements, an unpredictable therapeutic response.

Less common

Confusion, delirium; dark saliva, urine, or sweat.

Possible interactions

Other medicaments:

Levodopa taken concurrently with:

• benzodiazepines may blunt the therapeutic benefit of levodopa.
• bromocriptine (Parlodel) may result in decreased blood levels of bromocriptine.
• bupropion (Wellbutrin, Zyban) may increase adverse effects.
• cisapride (Propulsid) may increase adverse effects.
• clonidine (Catapres) can result in decreased therapeutic benefit of levodopa; avoid this combination.
• fentanyl/droperidol (Innovar) can cause muscular rigidity.
• indinavir (Crixivan) may lead to severe movement problems (dyskinesias).
• isoniazid (INH) may cause flushing, worsening of symptoms or increased blood pressure.
• monoamine oxidase (MAO) type A inhibitor medicaments can cause a dangerous rise in blood pressure and body temperature; do not combine these medicaments.
• phenothiazines may blunt therapeutic benefits of levodopa.
• reserpine (Naquival, others) may blunt the therapeutic benefits of levodopa; avoid this combination.
• risperidone (Risperdal) can blunt the therapeutic benefits of levodopa; avoid this combination.
• tolcapone (Tasmar) may lead to vitiligo (skin lesions).
• tricyclic antidepressants may decrease the therapeutic effect of levodopa.

The following medicaments may decrease the effects of levodopa:

• amoxapine (Asendin).
• chlordiazepoxide (Librium) or other benzodiazepines.
• iron salts.
• phenytoin (Dilantin, etc.) or fosphenytoin (Cerebyx).
• pyridoxine (vitamin B6).
• risperidone (Risperdal).

Foods:

Insofar as possible, do not take concurrently with protein foods; proteins compete for absorption.

Herbal medicines or minerals:

Calabar bean (chop nut, Fabia, ordeal nut, others) is unsafe when taken by mouth (physostigmine is the active ingredient) and should never be taken by people with Parkinson's disease. Octacosanol (a cousin of vitamin E) can worsen movement problems and should also be avoided.
If taken alone (without carbidopa), watch for tingling of the extremities (peripheral neuritis). Small (10 mg or less) doses of pyridoxine (vitamin B6) may help. Larger doses can decrease the effectiveness of levodopa. If taking Sinemet; supplemental pyridoxine is not required. Rare reports of vitamin C (ascorbic acid) decreasing nausea and other side effects have been made.

Marijuana smoking:

Increased fatigue and lethargy; possible accentuation of orthostatic hypotension.

Exposure to heat:

This medicament can cause flushing and excessive sweating and predispose to heat exhaustion.

Occurrence of unrelated illness:

Dark-colored skin lesions should be evaluated carefully by your doctor, as they may be malignant melanoma. White blood cell counts should be closely followed if you develop an infection.

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