Class: Anticholinergic Agents
VA Class: AU350
CAS Number: 132-17-2
Brands: Cogentin

Medically reviewed by Drugs.com. Last updated on Sep 21, 2020.

• Uses
• Dosage
• Cautions
• Interactions
• Patient advice
• Preparations

Introduction

Antimuscarinic antiparkinsonian agent.

Uses for Benztropine

Parkinsonian Syndrome

Adjunctive treatment of all forms of parkinsonian syndrome.^a

May be used as monotherapy or combined with other antiparkinsonian agents (e.g., carbidopa-levodopa).^{a b}

Drug-Induced Extrapyramidal Reactions

Control of extrapyramidal reactions (e.g., acute dystonia) induced by antipsychotic agents (e.g., phenothiazines).^a

Does not alleviate symptoms of tardive dyskinesia, and in some instances may aggravate them.^{a b c} Use not recommended.^{a b c}

Benztropine Dosage and Administration

Administration

Administered orally or by IM injection.^{a b}

Also may be given IV.^b Onset is rapid after either IM or IV injection, with no important difference in onset.^b Manufacturer states there usually is no need to administer IV and does not provide specific instructions for IV administration.^b

Oral Administration

Administered as a single dose at bedtime or in divided doses 2–4 times daily.^{a b}

IM Administration

Reserve for patients who cannot take oral medication or for emergency situations (e.g., acute dystonia).^{a b}

Dosage

Available as benztropine mesylate; dosage is expressed in terms of the salt.^{a b}

Geriatric patients or those with less than average body weight generally cannot tolerate high dosages of the drug.^{a b}

Pediatric Patients

Manufacturers make no specific dosage recommendations for children ≥ 3 years of age.^{a b} (See Pediatric Use under Cautions.)

Adults

Parkinsonian Syndrome

May require periodic dosage adjustments to maintain optimum symptomatic relief in patients receiving concomitant levodopa or combination levodopa-carbidopa therapy.^a

If used to replace or supplement other antiparkinsonian drugs, change should be gradual, with dosage of previous medication reduced as benztropine dosage is increased.^a

Avoid abrupt discontinuance of concomitantly administered antiparkinsonian drugs.^a

Idiopathic Parkinsonian Syndrome

Oral

Initially, 0.5–1 mg as a single dose at bedtime.^b Dosages may be increased by 0.5-mg increments at 5–6 day intervals up to a maximum of 6 mg daily.^b

Usual dosage: 1–2 mg daily (range: 0.5–6 mg daily).^b

IM

Initially, 0.5–1 mg as a single dose at bedtime.^a Dosages may be increased by 0.5-mg increments at 5- to 6-day intervals up to a maximum of 6 mg daily.^a

Usual dosage: 1–2 mg daily (range: 0.5–6 mg daily).^{a b}

Postencephalitic Parkinsonian Syndrome

Oral

Initially, 2 mg daily, given in 1 or more divided doses.^b In highly sensitive patients, may give instead as a single 0.5 mg dose at bedtime.^b Dosages may be increased by 0.5-mg increments at 5- to 6-day intervals up to a maximum of 6 mg daily.^b

Usual dosage: 1–2 mg daily (range: 0.5–6 mg daily).^b

IM

Initially, 2 mg daily, given in 1 or more divided doses.^a In highly sensitive patients, may give instead as a single 0.5 mg dose at bedtime.^a Dosages may be increased by 0.5-mg increments at 5–6 day intervals up to a maximum of 6 mg daily.^a

Usual dosage: 1–2 mg daily (range: 0.5–6 mg daily).^a

Drug-Induced Extrapyramidal Reactions

Oral

1–4 mg once or twice daily.^b

For extrapyramidal disorders that develop shortly after initiation of antipsychotic therapy, 1–2 mg 2 or 3 times daily usually provides relief within 1 or 2 days.^b Evaluate need for continued therapy after 1–2 weeks.^b

IM

1–4 mg once or twice daily.^a

For extrapyramidal disorders that develop shortly after initiation of antipsychotic therapy, 1–2 mg 2 or 3 times daily usually provides relief within 1 or 2 days.^a Evaluate need for continued therapy after 1–2 weeks.^a

Acute Dystonia

IM

1–2 mg, as a single dose.^a

Prescribing Limits

Adults

Parkinsonian Syndrome

Oral

Maximum 6 mg daily.^b

IM

Maximum 6 mg daily.^a

Cautions for Benztropine

Contraindications

• Known hypersensitivity to benztropine or any ingredient in the formulation.^{a b}

• Children < 3 years of age.^{a b}

Warnings/Precautions

Warnings

Pregnancy

Safe use during pregnancy has not been established.^{a b}

Cognitive/Physical Impairment

Risk of impaired mental alertness or physical coordination required for performing hazardous tasks (e.g., driving or operating machinery).^{a b}

Drug Interactions

Concomitant use with phenothiazines or tricyclic antidepressants associated with potentially fatal paralytic ileus, hyperthermia, or heat stoke.^{a b} Advise patients to promptly notify clinicians if adverse GI effects, fever, or heat intolerance occur if used concomitantly with these drugs or other drugs with anticholinergic or antidopaminergic (e.g., haloperidol) effects.^{a b} (See Interactions.)

Anhidrosis

Possibly severe anhidrosis and fatal hyperthermia.^{a b} Use with caution in hot weather, particularly when given concomitantly with other anticholinergic drugs to chronically ill or alcoholic patients, those who have CNS disease, and those engaged in manual labor.^{a b} Decrease dosages as needed to maintain ability to perspire.^{a b}

General Precautions

Adequate Patient Monitoring

Has cumulative effects; continue to monitor patients, particularly those with tendency toward tachycardia or with prostatic hypertrophy.^{a b}

Musculoskeletal Effects

Possible complaints of weakness and inability to move particular muscle groups, particularly at large dosages; adjust dosages as required.^{a b}

CNS Effects

Possible mental confusion and excitement, particularly with large dosages or in susceptible patients.^{a b} Visual hallucinations also possible.^{a b} (See Dosage and Administration: Dosage.)

Risk of intensification of mental symptoms or precipitation of toxic psychosis in patients with mental disorders receiving phenothiazines, especially at beginning of therapy or during dosage adjustment; monitor closely.^{a b} (See Specific Drugs under Interactions.)

Tardive Dyskinesia

Not recommended for use in patients with tardive dyskinesia.^{a b} (See Drug-Induced Extrapyramidal Reactions under Uses.)

Renal Effects

Possible dysuria or urinary retention.^{a b}

Glaucoma

Consider risks of glaucoma.^{a b} Probably should not be used in patients with angle-closure glaucoma.^{a b e}

Specific Populations

Pregnancy

Category C.^d See Warnings under Cautions.

Pediatric Use

Safety and efficacy not established in children <3 years of age.^{a b} (See Cautions: Contraindications.)

Use with caution in children >3 years of age because of adverse anticholinergic effects.^{a b}

Common Adverse Effects

Dry mouth, blurred vision, mydriasis, nausea, nervousness, tachycardia, paralytic ileus, constipation.^{c e}

Interactions for Benztropine

Specific Drugs

Stability

Storage

Oral

Tablets

< 30°C.^b

Parenteral

Solution

< 40°C, preferably between 15–30°C; avoid freezing.^c

Compatibility

For information on systemic interactions resulting from concomitant use, see Interactions.

Drug Compatibility

For information on IV injection of benztropine, see Administration under Dosage and Administration.

Actions

• Possesses both anticholinergic and antihistaminic effects, although only the former have been established as therapeutically important in management of parkinsonism.^a

Advice to Patients

• Potential for drug to impair mental alertness or physical coordination; use caution when driving or operating machinery until effects on individual are known.^{a b}

• Risk of hyperthermia.^{a b}

• Importance of promptly notifying clinicians of adverse GI effects, fever, or heat intolerance, particularly if also receiving phenothiazines, haloperidol, or other drugs with anticholinergic or antidopaminergic activity.^{a b}

• Importance of women informing their clinician if they are or plan to become pregnant or paln to breast-feed.^{a b}

• Importance of informing clinicians of existing or contemplated concomitant therapy, including prescription and OTC drugs, as well as concomitant illnesses.^{a b}

• Importance of informing patients of other important precautionary information.^{a b} (See Cautions.)

Preparations

Excipients in commercially available drug preparations may have clinically important effects in some individuals; consult specific product labeling for details.

Please refer to the ASHP Drug Shortages Resource Center for information on shortages of one or more of these preparations.

* available from one or more manufacturer, distributor, and/or repackager by generic (nonproprietary) name

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