benztropine

Absorption: Well absorbed following PO and IM administration. IV administration results in complete bioavailability.

Distribution: Unknown.

Metabolism/Excretion: Unknown.

Half-Life: Unknown.

Time/Action Profile ⬆ ⬇

(antidyskinetic activity)

ROUTE	ONSET	PEAK	DURATION
PO	1–2 hr	several days	24 hr
IM, IV	within min	unknown	24 hr

Contraind./Precautions ⬆ ⬇

Contraindicated in:

Hypersensitivity;
Angle-closure glaucoma;
Tardive dyskinesia;
Pedi: Children 3 yr.

Use Cautiously in:

Prostatic hyperplasia;
Seizure disorders;
Cardiac arrhythmias;
OB: Safety not established;
Geri: Appears on Beers list. Not recommended for prevention or treatment of extrapyramidal symptoms due to antipsychotics in older adults; more effective agents available for treatment of Parkinson's disease. Avoid use of oral formulation in older adults.

Adv. Reactions/Side Effects ⬆ ⬇

CV: arrhythmias, hypotension, palpitations, tachycardia

Derm: ↓sweating

EENT: blurred vision, dry eyes, mydriasis

GI: constipation, dry mouth, ileus, nausea

GU: hesitancy, urinary retention

Neuro: confusion, depression, dizziness, hallucinations, headache, sedation, weakness

Interactions ⬆ ⬇

Drug-drug:

Additive anticholinergic effects with drugs sharing anticholinergic properties, such as antihistamines, phenothiazines, quinidine, disopyramide, and tricyclic antidepressants.
Counteracts the cholinergic effects of bethanechol.
Antacids and antidiarrheals may ↓ absorption.

Drug-Natural Products:

↑anticholinergic effect with angel's trumpet, jimson weed, and scopolia.

Route/Dosage ⬆ ⬇

Parkinsonism

PO (Adults ): 1–2 mg/day in 1–2 divided doses (range 0.5–6 mg/day).

Acute Dystonic Reactions

IM IV (Adults ): 1–2 mg, then 1–2 mg PO twice daily.

Drug-Induced Extrapyramidal Reactions

PO IM IV (Adults ): 1–4 mg given once or twice daily (1–2 mg 2–3 times daily may also be used PO).

Availability ⬆ ⬇

(Generic available)

Tablets: 0.5 mg; 1 mg; 2 mg
Solution for injection: 1 mg/mL

Assessment ⬆ ⬇

Assess parkinsonian and extrapyramidal symptoms (restlessness or desire to keep moving, rigidity, tremors, pill rolling, masklike face, shuffling gait, muscle spasms, twisting motions, difficulty speaking or swallowing, loss of balance control) before and during therapy.
- Assess bowel function daily. Monitor for constipation, abdominal pain, distention, or absence of bowel sounds.
- Monitor intake and output ratios and assess patient for urinary retention (dysuria, distended abdomen, infrequent voiding of small amounts, overflow incontinence).
Patients with mental illness are at risk of developing exaggerated symptoms of their disorder during early therapy with benztropine. Hold benztropine and notify health care professional if significant behavioral changes occur.
IM/IV: Monitor pulse and BP closely and maintain bedrest for 1 hr after administration. Advise patients to change positions slowly to minimize orthostatic hypotension.

Implementation ⬆ ⬇

PO: Administer with food or immediately after meals to minimize gastric irritation. May be crushed and administered with food if patient has difficulty swallowing.
IM: Parenteral route is used only for dystonic reactions.

IV Administration:

IV route is rarely used because onset is same as with IM route.
Rate: Administer at a rate of 1 mg over 1 min.

Patient/Family Teaching ⬆ ⬇

Encourage patient to take benztropine as directed. Take missed doses as soon as possible, up to 2 hr before the next dose. Taper gradually when discontinuing or a withdrawal reaction may occur (anxiety, tachycardia, insomnia, return of parkinsonian or extrapyramidal symptoms).
May cause drowsiness or dizziness. Advise patient to avoid driving or other activities that require alertness until response to the drug is known.
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.
Caution patient to change positions slowly to minimize orthostatic hypotension.
Instruct patient to notify health care professional if difficulty with urination, constipation, abdominal discomfort, rapid or pounding heartbeat, confusion, eye pain, or rash occurs.
Advise patient to confer with health care professional before taking OTC medications, especially cold remedies, or drinking alcoholic beverages.
Caution patient that this medication decreases perspiration. Overheating may occur during hot weather. Patient should notify health care professional if unable to remain indoors in an air-conditioned environment during hot weather.
Advise patient to avoid taking antacids or antidiarrheals within 1–2 hr of this medication.
Emphasize the importance of routine follow-up exams.
Rep: Advise females of reproductive potential to notify health care professional if pregnancy is planned or suspected or if breastfeeding.

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Pronunciation ⬇

Classifications ⬆ ⬇

Indications ⬆ ⬇

Action ⬆ ⬇

Pharmacokinetics ⬆ ⬇