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tolcapone (tole-ka-pone)



Therapeutic: antiparkinson agents

Pharmacologic: catechol-O-methyltransferase inhibitors


Management of Parkinson's disease with carbidopa/levodopa in patients without severe movement abnormalities who do not respond to other treatments.


Acts as a selective and reversible inhibitor of the enzyme catechol-O-methyltransferase. Inhibition of this enzyme prevents the breakdown of levodopa, greatly increasing its availability to the CNS. Therapeutic Effects: Prolongs duration of response to levodopa without end-of-dose motor fluctuations. ↓ signs and symptoms of Parkinson's disease.

Adverse Reactions/Side Effects

CNS: headache, sleep disorder, hallucinations, syncope. CV: orthostatic hypotension. GI: HEPATOTOXICITY, HEPATIC FAILURE, constipation, diarrhea, anorexia, elevated liver enzymes, nausea, vomiting. GU: hematuria, yellow discoloration of urine. Derm: increased sweating. Neuro: dyskinesia, dystonia.


Examination and Evaluation

  • Be alert for signs of hepatotoxicity and liver failure, including anorexia, abdominal pain, severe nausea and vomiting, yellow skin or eyes, fever, sore throat, malaise, weakness, facial edema, lethargy, and unusual bleeding or bruising. Notify physician of these signs immediately.

  • Assess gait and motor function to help determine antiparkinson effects, especially when starting drug therapy or during dosing changes or addition of other antparkinson drugs. Motor function should be assessed at different times of the day, such as when drugs are reaching peak therapeutic levels (i.e., 30–60 min after oral dose), as well as when drug effects are minimal (just before the next dose).

  • Document increased motor side effects such as involuntary movements (dyskinesias), changes in muscle tone (dystonia), fluctuations in response (on-off phenomenon, end-of-dose akinesia), or other abnormal movement patterns. Notify physician because increased motor side effects might require dose adjustment or a change in medication regimen.

  • Monitor hallucinations and other psychologic problems. Repeated or excessive symptoms may require change in dose or medication.

  • Assess blood pressure (BP) when patient assumes a more upright position (lying to standing, sitting to standing, lying to sitting). Document orthostatic hypotension and contact physician when systolic BP falls >20 mm Hg, or diastolic BP falls >10 mm Hg.


  • Implement therapeutic exercises (coordination exercises, gait training, cardiovascular conditioning) to complement the effects of drug therapy and help achieve optimal function.

  • Guard against falls and trauma (hip fractures, head injury, and so forth). Implement fall-prevention strategies (See Appendix E), especially if patient exhibits Parkinson's symptoms (postural instability, rigidity) combined with drug side effects (dyskinesias, fainting).

  • To minimize orthostatic hypotension and syncope, patient should move slowly when assuming a more upright position.

Patient/Client-Related Instruction

  • Advise patient to avoid alcohol because of the increased risk of sedation and adverse effects.

  • Advise patient about the likelihood of GI reactions such as nausea, vomiting, diarrhea, and ...

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