COMT Inhibitors

Available Doses: 200 mg

Typical Treatment Regimen: 4 to 8 times per day (with each levodopa dose)

Side Effects: Diarrhea, discolored urine, enhanced side effects of levodopa (especially dyskinesia and confusion)

Indications for Usage: Combination therapy with levodopa for motor fluctuations, not used without levodopa.

Available Doses: 100 mg, 200 mg

Typical Treatment Regimen: 100 mg up to 3 times per day, to a maximum of 200 mg 3 times per day

Side Effects: Diarrhea, discolored urine, enhanced side effects of levodopa (especially dyskinesia — involuntary muscle movements in response to levodopa —and confusion), risk of liver damage (need regular blood tests to check liver functions)

Indications for Usage: Combination therapy with levodopa for motor fluctuations, not used without levodopa. Should only be used after all PD medications have been tried and should be discontinued if no benefit in 3 weeks.

Due to instances of liver function abnormalities during clinical trials of tolcapone, the Food and Drug Administration mandates that blood tests of liver function be conducted at the beginning of the treatment and every six months after beginning treatment

This is a combination drug which includes entacapone and carbidopa-levodopa in one pill. It is more convenient compared with carbidopa-levodopa and entacapone taken separately.

Available Doses: 12.5-50-200 mg, 18.75-75-200 mg, 25-100-200 mg, 31.25-125-200 mg, 37.5-150-200 mg, 50-200-200 mg

Typical Treatment Regimen: 150 to 1,600 mg of levodopa total daily dose, depending on daily need (maximum 8 tablets daily)

Common Side Effects: nausea, lower blood pressure, confusion, dyskinesia (extra movements), diarrhea and discolored urine

Indications for Usage: Replacement for carbidopa-levodopa for motor fluctuations, with the benefit of entacapone, which extends the life of levodopa

Available Doses: 25 mg, 50 mg capsules

Typical Treatment Regimen: 50 mg by mouth once daily at bedtime

Side Effects: dyskinesia, constipation, low blood pressure/dizziness, weight loss

Indications for Usage: Combination therapy with levodopa for "off" time (not pharmacologically active by itself).

Please note that the side effects listed in the tables that accompany each class of medication are the most commonly experienced. Not all individuals will experience such side effects. Careful adjustments to dosage or the timing of individual doses can often effectively limit or eliminate side effects for many people.

Speak to your doctor immediately if you experience any side effects. For a complete description of each drug and its possible side effects, please request a “package insert” from your pharmacist for each drug used. It is recommended that all prescriptions be filled at the same pharmacy to avoid interactions between medications. Interactions can be dangerous and even life-threatening, so make sure the pharmacist knows of all medications and supplements being taken, including over-the-counter medications and supplements.

Caution: Parkinson’s medications may have interactions with certain foods, other medications, vitamins, herbal supplements, over-the-counter cold pills and other remedies. Anyone taking a PD medication should talk to their doctor and pharmacist about potential drug interactions.