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Pharmacologic class: Anticholinergic
Therapeutic class: Antiparkinsonian
Pregnancy risk category C
Inhibits cholinergic excitatory pathways and restores balance of dopamine and acetylcholine in CNS, thereby decreasing excess salivation, rigidity, and tremors (parkinsonian symptoms)
Injection: 1 mg/ml in 2-ml ampules
Tablets: 0.5 mg, 1 mg, 2 mg
Indications and dosages
Adults: Initially, 1 to 2 mg/day P.O. or I.M. at bedtime or in two or four divided doses. Dosage range is 0.5 to 6 mg/day.
➣ Acute dystonic reactions
Adults: Initially, 1 to 2 mg I.M. or I.V., then 1 to 2 mg P.O. b.i.d.
➣ Drug-induced extrapyramidal reactions (except tardive dyskinesia)
Adults: 1 to 4 mg P.O. or I.M. once or twice daily
• Elderly patients
• Excessive salivation
• Hypersensitivity to drug
• Angle-closure glaucoma
• Tardive dyskinesia
• Children younger than age 3
Use cautiously in:
• seizure disorders, arrhythmias, tachycardia, hypertension, hypotension, hepatic or renal dysfunction, alcoholism, prostatic hypertrophy
• elderly patients
• pregnant or breastfeeding patients.
• Give after meals to prevent GI upset.
• Crush tablets if patient has difficulty swallowing them.
• Know that I.V. route is seldom used.
• Be aware that entire dose may be given at bedtime. (Drug has long duration of action.)
CNS: confusion, depression, dizziness, hallucinations, headache, weakness, memory impairment, nervousness, delusions, euphoria, paresthesia, sensation of heaviness in limbs, toxic psychosis
CV: hypotension, palpitations, tachycardia, arrhythmias
EENT: blurred vision, diplopia, mydriasis, angle-closure glaucoma
GI: nausea, constipation, dry mouth, ileus
GU: urinary hesitancy or retention, dysuria, difficulty maintaining erection
Musculoskeletal: paratonia, muscle weakness and cramps
Skin: rash, urticaria, decreased sweating, dermatoses
Drug-drug. Antacids, antidiarrheals: decreased benztropine absorption
Antihistamines, bethanechol, disopyramide, phenothiazines, quinidine, tricyclic antidepressants: additive anticholinergic effects
Drug-herbs. Angel's trumpet, jimsonweed, scopolia: increased anticholinergic effects
Drug-behaviors. Alcohol use: increased sedation
• Monitor blood pressure closely, especially in elderly patients.
• Monitor fluid intake and output; check for urinary retention.
• Assess for signs and symptoms of ileus, including constipation and abdominal distention.
• Advise patient to use caution during activities that require physical or mental alertness, because drug causes sedation.
• Tell patient to avoid increased heat exposure.
☞ Caution patient not to stop therapy abruptly.
• As appropriate, review all other significant and life-threatening adverse reactions and interactions, especially those related to the drugs, herbs, and behaviors mentioned above.
benztropineAn anticholinergic used to manage parkinsonism, Parkinson’s disease and dystonia.
In high doses can cause nervousness, impaired memory, numbness, listlessness, depression, confusion, excitement, and hallucinations; GI symptoms include dry mouth, constipation, nausea, vomiting, blurred vision, mydriasis, hyperthermia, anhidrosis, urinary retention, dysuria, weakness, rash and tachycardia.