Benztropine

INTRODUCTION

Indications

Adjunctive treatment of all forms of Parkinson's disease, including drug-induced extrapyramidal effects and acute dystonic reactions.

Action

Blocks cholinergic activity in the CNS, which is partially responsible for the symptoms of Parkinson's disease. Restores the natural balance of neurotransmitters in the CNS. Therapeutic Effects: Reduction of rigidity and tremors.

Adverse Reactions/Side Effects

CNS: confusion, depression, dizziness, hallucinations, headache, sedation, weakness. EENT: blurred vision, dry eyes, mydriasis. CV: arrhythmias, hypotension, palpitations, tachycardia. GI: constipation, dry mouth, ileus, nausea. GU: hesitancy, urinary retention. Misc: decreased sweating.

PHYSICAL THERAPY IMPLICATIONS

Examination and Evaluation

• Assess patient's gait and motor function to help document antiparkinson effects, especially when starting drug therapy, or during dosing changes or addition of other antiparkinson drugs. Motor function should be assessed at different times of the day, such as when drugs are reaching therapeutic levels (i.e., 1–2 hr after oral dose), as well as when drug effects are minimal (just before the next dose).

• Assess heart rate, ECG, and heart sounds, especially during exercise (See Appendices G, H). Report fast heart rate (tachycardia) or signs of other arrhythmias, including palpitations, chest discomfort, shortness of breath, fainting, and fatigue/weakness.

• Assess blood pressure (BP) periodically and compare to normal values (See Appendix F). Report low blood pressure (hypotension), especially if patient experiences dizziness, fatigue, or other symptoms.

• Assess dizziness and drowsiness that might affect gait, balance, and other functional activities (See Appendix C). Report balance problems and functional limitations to the physician and nursing staff, and caution the patient and family/caregivers to guard against falls and trauma.

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

Interventions

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

• Because of the risk of arrhythmias and abnormal BP responses, use caution during aerobic exercise and other forms of therapeutic exercise. Assess exercise tolerance frequently (BP, heart rate, fatigue levels), and terminate exercise immediately if any untoward responses occur (See Appendix L).

• 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 (dizziness, blurred vision, weakness).

Patient/Client-Related Instruction

• Instruct patient to report other bothersome side effects, including severe or prolonged headache, vision problems, decreased sweating, urinary problems (hesitancy, retention), or GI problems (nausea, constipation, dry mouth).

Pharmacokinetics

Absorption:...