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Benztropine

Pronunciation

Pronunciation

(BENZ troe peen)

Index Terms

  • Benzatropine
  • Benztropine Mesylate
  • Cogentin

Dosage Forms

Excipient information presented when available (limited, particularly for generics); consult specific product labeling.

Solution, Injection, as mesylate:

Cogentin: 1 mg/mL (2 mL)

Generic: 1 mg/mL (2 mL)

Tablet, Oral, as mesylate:

Generic: 0.5 mg, 1 mg, 2 mg

Brand Names: U.S.

  • Cogentin

Pharmacologic Category

  • Anti-Parkinson Agent, Anticholinergic
  • Anticholinergic Agent

Pharmacology

Possesses both anticholinergic and antihistaminic effects. In vitro anticholinergic activity approximates that of atropine; in vivo it is only about half as active as atropine. Animal data suggest its antihistaminic activity and duration of action approach that of pyrilamine maleate.

Metabolism

Hepatic (N-oxidation, N-dealkylation, and ring hydroxylation) (from animal studies only) (Brocks 1999)

Onset of Action

IM, IV: Within a few minutes; there is no significant difference between onset of effect after intravenous or intramuscular injection

Oral: Within 1 hour

Time to Peak

Plasma: Oral: 7 hours (Brocks 1999)

Use: Labeled Indications

Extrapyramidal disorders: Aid in the control of extrapyramidal disorders (except tardive dyskinesia) due to neuroleptic drugs (eg, phenothiazines).

Parkinsonism: Adjunctive therapy of all forms of parkinsonism.

Contraindications

Hypersensitivity to benztropine or any component of the formulation; children <3 years of age (due to atropine-like adverse effects)

Dosing: Adult

Drug-induced extrapyramidal symptoms: Oral, IM, IV:

Initial: 1 to 2 mg 2 to 3 times daily for reactions developing soon after initiation of antipsychotic medication. Usually provides relief within 1 to 2 days. Titrate gradually at 0.5 mg increments at 5- to 6-day intervals based on response and tolerability. Usual dosage is 1 to 4 mg once or twice daily up to a maximum daily dose of 6 mg. Treatment may be continued for 1 to 2 weeks, after which treatment should be withdrawn to reassess continued need for therapy. May reinitiate benztropine if symptoms recur (Holloman, 1997; Tonda, 1994). Note: Certain drug-induced extrapyramidal disorders that develop slowly may not respond to benztropine.

Acute dystonic reactions: 1 to 2 mg to treat acute reactions followed by 1 to 2 mg (orally) 1 to 2 times daily for up to 7 to 28 days to prevent recurrence. Note: IM/IV administration is preferred over oral administration for severe acute reactions due to the faster onset of action (Holloman, 1997; Tonda, 1994).

Parkinsonism: Oral, IM, IV:

Idiopathic parkinsonism: Initial: 0.5 to 1 mg daily at bedtime or in 2 to 4 divided doses. Titrate in 0.5 mg increments every 5 to 6 days based on response and tolerability. Usual dose: 1 to 2 mg daily (range: 0.5 to 6 mg daily) although some patients may need 4 to 6 mg daily; maximum: 6 mg daily

Postencephalitic parkinsonism: Initial: 2 mg daily as a single dose at bedtime or in 2 to 4 divided doses; a lower initial dose of 0.5 mg at bedtime may be considered in highly sensitive patients. Titrate in 0.5 mg increments every 5 to 6 days based on response and tolerability. Usual dose: 1 to 2 mg daily (range: 0.5 to 6 mg daily); maximum: 6 mg daily.

Note: Lower initial doses may be appropriate for older and thinner patients.

Dosing: Geriatric

Refer to adult dosing. Start at low end of dosing range and increase only as needed and as tolerated.

Dosing: Pediatric

Drug-induced extrapyramidal symptoms: Oral, IM, IV:

Children ≥3 years (off-label dose): 0.02 to 0.05 mg/kg/dose 1 to 2 times daily (Bellman, 1974; Habre, 1999; Joseph, 1995; Teoh, 2002)

Adolescents (off-label dose): 1 to 4 mg every 12 to 24 hours (Nelson, 1996)

Dosing: Renal Impairment

There are no dosage adjustments provided in the manufacturer’s labeling.

Dosing: Hepatic Impairment

There are no dosage adjustments provided in the manufacturer’s labeling.

Administration

Oral: Administer with or without food.

Injectable: Administer IM or IV if oral route is unacceptable. Manufacturer’s labeling states there is no difference in onset of effect after IV or IM injection and therefore there is usually no need to use the IV route. No specific instructions on administering benztropine IV are provided in the labeling. The IV route has been reported in the literature (slow IV push when reported), although specific instructions are lacking (Duncan, 2001; Lydon, 1998; Sachdev, 1993; Schramm, 2002).

Dietary Considerations

Tablet may be taken with or without food.

Storage

Store at 20°C to 25°C (68°F to 77°F).

Drug Interactions

AbobotulinumtoxinA: Anticholinergic Agents may enhance the anticholinergic effect of AbobotulinumtoxinA. Monitor therapy

Acetylcholinesterase Inhibitors: Anticholinergic Agents may diminish the therapeutic effect of Acetylcholinesterase Inhibitors. Acetylcholinesterase Inhibitors may diminish the therapeutic effect of Anticholinergic Agents. Monitor therapy

Aclidinium: May enhance the anticholinergic effect of Anticholinergic Agents. Avoid combination

Analgesics (Opioid): Anticholinergic Agents may enhance the adverse/toxic effect of Analgesics (Opioid). Specifically, the risk for constipation and urinary retention may be increased with this combination. Monitor therapy

Anticholinergic Agents: May enhance the adverse/toxic effect of other Anticholinergic Agents. Monitor therapy

Cannabinoid-Containing Products: Anticholinergic Agents may enhance the tachycardic effect of Cannabinoid-Containing Products. Exceptions: Cannabidiol. Monitor therapy

Chloral Betaine: May enhance the adverse/toxic effect of Anticholinergic Agents. Monitor therapy

Cimetropium: Anticholinergic Agents may enhance the anticholinergic effect of Cimetropium. Avoid combination

Eluxadoline: Anticholinergic Agents may enhance the constipating effect of Eluxadoline. Avoid combination

Gastrointestinal Agents (Prokinetic): Anticholinergic Agents may diminish the therapeutic effect of Gastrointestinal Agents (Prokinetic). Monitor therapy

Glucagon: Anticholinergic Agents may enhance the adverse/toxic effect of Glucagon. Specifically, the risk of gastrointestinal adverse effects may be increased. Avoid combination

Glycopyrrolate (Oral Inhalation): Anticholinergic Agents may enhance the anticholinergic effect of Glycopyrrolate (Oral Inhalation). Avoid combination

Ioflupane I 123: Benztropine may diminish the diagnostic effect of Ioflupane I 123. Monitor therapy

Ipratropium (Oral Inhalation): May enhance the anticholinergic effect of Anticholinergic Agents. Avoid combination

Itopride: Anticholinergic Agents may diminish the therapeutic effect of Itopride. Monitor therapy

Levosulpiride: Anticholinergic Agents may diminish the therapeutic effect of Levosulpiride. Avoid combination

Mianserin: May enhance the anticholinergic effect of Anticholinergic Agents. Monitor therapy

Mirabegron: Anticholinergic Agents may enhance the adverse/toxic effect of Mirabegron. Monitor therapy

Nitroglycerin: Anticholinergic Agents may decrease the absorption of Nitroglycerin. Specifically, anticholinergic agents may decrease the dissolution of sublingual nitroglycerin tablets, possibly impairing or slowing nitroglycerin absorption. Avoid combination

OnabotulinumtoxinA: Anticholinergic Agents may enhance the anticholinergic effect of OnabotulinumtoxinA. Monitor therapy

Oxatomide: May enhance the anticholinergic effect of Anticholinergic Agents. Avoid combination

Potassium Chloride: Anticholinergic Agents may enhance the ulcerogenic effect of Potassium Chloride. Management: Patients on drugs with substantial anticholinergic effects should avoid using any solid oral dosage form of potassium chloride. Avoid combination

Pramlintide: May enhance the anticholinergic effect of Anticholinergic Agents. These effects are specific to the GI tract. Consider therapy modification

Ramosetron: Anticholinergic Agents may enhance the constipating effect of Ramosetron. Monitor therapy

RimabotulinumtoxinB: Anticholinergic Agents may enhance the anticholinergic effect of RimabotulinumtoxinB. Monitor therapy

Secretin: Anticholinergic Agents may diminish the therapeutic effect of Secretin. Management: Avoid using drugs with substantial anticholinergic effects in patients receiving secretin whenever possible. If such agents must be used in combination, monitor closely for a diminished response to secretin. Consider therapy modification

Thiazide and Thiazide-Like Diuretics: Anticholinergic Agents may increase the serum concentration of Thiazide and Thiazide-Like Diuretics. Monitor therapy

Tiotropium: Anticholinergic Agents may enhance the anticholinergic effect of Tiotropium. Avoid combination

Topiramate: Anticholinergic Agents may enhance the adverse/toxic effect of Topiramate. Monitor therapy

Umeclidinium: May enhance the anticholinergic effect of Anticholinergic Agents. Avoid combination

Adverse Reactions

Frequency not defined.

Cardiovascular: Tachycardia

Central nervous system: Confusion, depression, disorientation, heatstroke, hyperthermia, lethargy, memory impairment, nervousness, numbness of fingers, psychotic symptoms (exacerbation of pre-existing symptoms), toxic psychosis, visual hallucination

Dermatologic: Skin rash

Gastrointestinal: Constipation, nausea, paralytic ileus, vomiting, xerostomia

Genitourinary: Dysuria, urinary retention

Ophthalmic: Blurred vision, mydriasis

Warnings/Precautions

Concerns related to adverse effects:

• Anhidrosis/hyperthermia: May cause anhidrosis and hyperthermia, which may be severe; use with caution in hot weather or during exercise. The risk is increased in hot environments, particularly in the elderly, alcoholics, patients with CNS disease, and those with prolonged outdoor exposure. If there is evidence of anhidrosis, consider decreasing dose so the ability to maintain body heat equilibrium by perspiration is not impaired.

• Anticholinergic effects: May cause anticholinergic effects (constipation, xerostomia, blurred vision, urinary retention).

• CNS effects: May be associated with confusion, visual hallucinations or excitement (generally at higher dosages); intensification of symptoms or toxic psychosis may occur in patients with mental disorders. May cause CNS depression, which may impair physical or mental abilities; patients must be cautioned about performing tasks which require mental alertness (eg, operating machinery or driving).

• Weakness: When given in large doses or to susceptible patients, may cause weakness and inability to move particular muscle groups.

Disease-related concerns:

• Cardiovascular disease: Use with caution in patients with tachycardia.

• GI obstruction: Use with caution in patients with obstructive disease of the GI tract (eg, pyloric or duodenal obstruction).

• Glaucoma: Use with caution in patients with glaucoma; avoid use in angle-closure glaucoma.

• Prostatic hyperplasia/urinary stricture: Use with caution in patients with prostatic hyperplasia and/or urinary stricture or retention.

Concurrent drug therapy issues:

• Drug-drug interactions: Potentially significant interactions may exist, requiring dose or frequency adjustment, additional monitoring, and/or selection of alternative therapy. Consult drug interactions database for more detailed information.

Special populations:

• Elderly: Use with caution in patients >65 years of age; response in elderly may be altered. Initiate at low doses and increase as needed while monitoring for adverse events.

• Pediatric: Use with caution in children >3 years of age due to its anticholinergic effects; dose has not been established. Use is contraindicated in children <3 years of age.

Other warnings/precautions:

• Tardive dyskinesia: Not recommended for use in patients with tardive dyskinesia; benztropine does not relieve symptoms of tardive dyskinesia and may potentially exacerbate symptoms.

Monitoring Parameters

Pulse, anticholinergic effects

Pregnancy Considerations

Animal reproduction studies have not been conducted. Paralytic ileus (which resolved rapidly) was reported in two newborns exposed to a combination of benztropine and chlorpromazine during the second and third trimesters and the last 6 weeks of pregnancy, respectively (Falterman, 1980).

Patient Education

• Discuss specific use of drug and side effects with patient as it relates to treatment. (HCAHPS: During this hospital stay, were you given any medicine that you had not taken before? Before giving you any new medicine, how often did hospital staff tell you what the medicine was for? How often did hospital staff describe possible side effects in a way you could understand?)

• Patient may experience nausea, vomiting or dry mouth. Have patient report immediately to prescriber signs of depression (suicidal ideation, anxiety, emotional instability, or confusion), hallucinations, confusion, severe anxiety, vision changes, eye pain, severe eye irritation, difficulty swallowing, difficulty speaking, lack of appetite, weight loss, difficult urination, painful urination, tachycardia, enlarged pupils, memory impairment, severe abdominal pain, severe constipation, lack of sweat, heat stroke, or high fever (HCAHPS).

• Educate patient about signs of a significant reaction (eg, wheezing; chest tightness; fever; itching; bad cough; blue skin color; seizures; or swelling of face, lips, tongue, or throat). Note: This is not a comprehensive list of all side effects. Patient should consult prescriber for additional questions.

Intended Use and Disclaimer: Should not be printed and given to patients. This information is intended to serve as a concise initial reference for health care professionals to use when discussing medications with a patient. You must ultimately rely on your own discretion, experience, and judgment in diagnosing, treating, and advising patients.

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