Pharmacologic Profile

General Use

Treatment of Parkinson's disease.

General Action and Information

Drugs used in the treatment of Parkinson's disease and other dyskinesias are aimed at restoring the natural balance of two major neurotransmitters in the CNS: acetylcholine and dopamine. The imbalance is a deficiency in dopamine that results in excessive cholinergic activity. Many of the drugs used are either anticholinergics (benztropine and trihexyphenidyl) or dopaminergic agonists (apomorphine, bromocriptine, levodopa/carbidopa, pramipexole, ropinirole, rotigotine). Entacapone and tolcapone inhibit the enzyme that breaks down levodopa, thereby enhancing its effects. Rasagiline and selegiline are MAO-B inhibitors that lead to ↑ concentrations of dopamine in the CNS.

Contraindications

Anticholinergics should be avoided in patients with angle-closure glaucoma.

Precautions

Use cautiously in patients with severe cardiac disease, pyloric obstruction, or prostatic enlargement.

Interactions

Pyridoxine, MAO inhibitors, benzodiazepines, phenytoin, phenothiazines, and haloperidol may antagonize the effects of levodopa. Agents that antagonize dopamine (phenothiazines, metoclopramide) may ↓ effectiveness of dopamine agonists.

Nursing Implications

Assessment

• Assess parkinsonian and extrapyramidal symptoms (akinesia, rigidity, tremors, pill rolling, mask facies, shuffling gait, muscle spasms, twisting motions, and drooling) before and throughout course of therapy. On-off phenomenon may cause symptoms to appear or improve suddenly.
• Monitor BP frequently during therapy. Instruct patient to remain supine during and for several hours after first dose of bromocriptine, as severe hypotension may occur.

Potential Nursing Diagnoses

• Impaired physical mobility (Indications)
• Risk for injury (Indications)
• Deficient knowledge related to disease processes and medication regimen (Patient/Family Teaching)

Implementation

• In the carbidopa/levodopa combination, the number following the drug name represents the milligram of each respective drug.

Patient/Family Teaching

• May cause drowsiness or dizziness. Advise patient to avoid driving or other activities that require alertness until response to medication is known.
• Caution patient to make position changes slowly to minimize orthostatic hypotension.
• Instruct patient that frequent rinsing of mouth, good oral hygiene, and sugarless gum or candy may decrease dry mouth. Patient should notify health care professional if dryness persists (saliva substitutes may be used). Also notify the dentist if dryness interferes with use of dentures.
• Advise patient to confer with health care professional before taking OTC medications, especially cold remedies, or drinking alcoholic beverages. Patients receiving levodopa should avoid multivitamins. Vitamin B₆ (pyridoxine) may interfere with levodopa's action.
• Caution patient that decreased perspiration may occur. Overheating may occur during hot weather. Patients should remain indoors in an air-conditioned environment during hot weather.
• Advise patient to increase activity, bulk, and fluid in diet to minimize constipating effects of medication.
• Advise patient to notify health care professional if confusion, rash, urinary retention, severe constipation, visual changes, or worsening of parkinsonian symptoms occur.

Evaluation/Desired Outcomes

• Resolution of parkinsonian signs and symptoms
• Resolution of drug-induced extrapyramidal symptoms.