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Pronunciation
(BENZ troe peen)
Generic Available (U.S.)
Yes
Index Terms
Brand Names: U.S.
Brand Names: Canada
Pharmacologic Category
Pharmacologic Category Synonyms
Use: Labeled Indications
Adjunctive treatment of Parkinson's disease; treatment of drug-induced extrapyramidal symptoms (except tardive dyskinesia)
Pregnancy Risk Factor
C
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).
Lactation
Excretion in breast milk unknown/use caution
Breast-Feeding Considerations
It is not known if benztropine is excreted in breast milk. Anticholinergic agents may suppress lactation.
Contraindications
Hypersensitivity to benztropine or any component of the formulation; pyloric or duodenal obstruction, stenosing peptic ulcers; bladder neck obstructions; achalasia; myasthenia gravis; children <3 years of age
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.
• CNS effects: May be associated with confusion or hallucinations (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, cardiac arrhythmias, hypertension, or hypotension.
• GI obstruction: Use with caution in patients with obstructive disease of the GI.
• Glaucoma: Use with caution in patients with glaucoma.
• Hepatic impairment: Use with caution in patients with hepatic impairment.
• Prostatic hyperplasia/urinary stricture: Use with caution in patients with prostatic hyperplasia and/or urinary stricture or retention.
• Renal impairment: Use with caution in patients with renal impairment.
Special populations:
• Elderly: Avoid use of oral benztropine in older adults for prevention of extrapyramidal symptoms with antipsychotics and alternative agents preferred in the treatment of Parkinson's disease. May be inappropriate in older adults depending on comorbidities (eg, dementia, delirium) due to its potent anticholinergic effects (Beers Criteria).
• Pediatrics: Use with caution in older children; dose has not been established.
Other warnings/precautions:
• Tardive dyskinesia: Does not relieve symptoms of tardive dyskinesia.
Adverse Reactions
Frequency not defined.
Cardiovascular: Tachycardia
Central nervous system: Confusion, disorientation, memory impairment, toxic psychosis, visual hallucinations
Dermatologic: Rash
Endocrine & metabolic: Heat stroke, hyperthermia
Gastrointestinal: Constipation, dry throat, ileus, nasal dryness, nausea, vomiting, xerostomia
Genitourinary: Urinary retention, dysuria
Ocular: Blurred vision, mydriasis
Miscellaneous: Fever
Metabolism/Transport Effects
Substrate of CYP2D6 (minor); Note: Assignment of Major/Minor substrate status based on clinically relevant drug interaction potential
Drug Interactions
AbobotulinumtoxinA: Anticholinergic Agents may enhance the anticholinergic effect of AbobotulinumtoxinA. Risk C: Monitor therapy
Acetylcholinesterase Inhibitors (Central): Anticholinergics may diminish the therapeutic effect of Acetylcholinesterase Inhibitors (Central). Acetylcholinesterase Inhibitors (Central) may diminish the therapeutic effect of Anticholinergics. If the anticholinergic action is a side effect of the agent, the result may be beneficial. Risk C: Monitor therapy
Anticholinergics: May enhance the adverse/toxic effect of other Anticholinergics. Exceptions: Levocabastine (Nasal); Paliperidone. Risk C: Monitor therapy
Cannabinoids: Anticholinergic Agents may enhance the tachycardic effect of Cannabinoids. Risk C: Monitor therapy
Ioflupane I 123: Benztropine may diminish the diagnostic effect of Ioflupane I 123. Risk C: Monitor therapy
OnabotulinumtoxinA: Anticholinergic Agents may enhance the anticholinergic effect of OnabotulinumtoxinA. Risk C: Monitor therapy
Peginterferon Alfa-2b: May decrease the serum concentration of CYP2D6 Substrates. Risk C: Monitor therapy
Potassium Chloride: Anticholinergic Agents may enhance the ulcerogenic effect of Potassium Chloride. Risk D: Consider therapy modification
Pramlintide: May enhance the anticholinergic effect of Anticholinergics. These effects are specific to the GI tract. Risk D: Consider therapy modification
RimabotulinumtoxinB: Anticholinergic Agents may enhance the anticholinergic effect of RimabotulinumtoxinB. Risk C: Monitor therapy
Secretin: Anticholinergic Agents may diminish the therapeutic effect of Secretin. Risk D: Consider therapy modification
Ethanol/Nutrition/Herb Interactions
Ethanol: Avoid ethanol (may increase CNS depression).
Compatibility
Y-site administration: Compatible: Fluconazole, tacrolimus.
Compatibility in syringe: Compatible: Chlorpromazine, fluphenazine, metoclopramide. Variable (consult detailed reference): Haloperidol.
Mechanism of Action
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. May also inhibit the reuptake and storage of dopamine, thereby prolonging the action of dopamine.
Pharmacodynamics/Kinetics
Onset of action: Oral: Within 1 hour; Parenteral: Within 15 minutes
Duration: 6-48 hours
Metabolism: Hepatic (N-oxidation, N-dealkylation, and ring hydroxylation)
Bioavailability: 29%
Dosage
Drug-induced extrapyramidal symptom: Oral, I.M., I.V.:
Children >3 years (unlabeled dose): 0.02-0.05 mg/kg/dose 1-2 times/day
Adults: 1-4 mg 1-2 times/day or 1-2 mg 2-3 times/day for reactions developing soon after initiation of antipsychotic medication; usually provides relief within 1-2 days, but may continue for up to 1-2 weeks; withdraw after 1-2 weeks to reassess continued need for therapy
Acute dystonia: Adults: I.M., I.V.: 1-2 mg
Parkinsonism, idiopathic or postencephalitic: Adults: Oral, I.M., I.V.: Usual dose: 1-2 mg/day; range: 0.5-6 mg/day in a single dose at bedtime or divided in 2-4 doses; titrate dose in 0.5 mg increments at 5- to 6-day intervals up to a maximum of 6 mg.
Elderly: Use caution or avoid; anticholinergics generally not tolerated in older adults.
Administration: Oral
May be given with or without food.
Administration: I.M.
May administer I.M. if oral route is unacceptable.
Administration: I.V.
May administer I.V. if oral route is unacceptable. Manufacturer's labeling states there is no difference in onset of effect after I.V. or I.M. injection and therefore there is usually no need to use the I.V. route. No specific instructions on administering benztropine I.V. are provided in the labeling. The I.V. route has been reported in the literature (slow I.V. push when reported), although specific instructions are lacking (Duncan, 2001; Lydon, 1998; Sachdev, 1993; Schramm, 2002).
Administration: I.V. Detail
pH: 5-8
Monitoring Parameters
Symptoms of EPS or Parkinson's, pulse, anticholinergic effects
Dietary Considerations
Tablet may be taken with or without food.
Patient Education
Take at the same time each day. Do not use alcohol. You may experience drowsiness, dizziness, confusion, blurred vision, increased susceptibility to heat stroke, decreased perspiration, or constipation. Report unresolved nausea, vomiting, or gastric disturbances; rapid or pounding heartbeat, chest pain, or palpitation; respiratory difficulty; CNS changes (hallucination, loss of memory, nervousness, etc); eye pain; prolonged fever; painful or difficult urination; unresolved constipation; increased muscle spasticity or rigidity; skin rash; or significant worsening of condition.
Geriatric Considerations
Anticholinergic agents are generally not well tolerated in the elderly (often results in bowel, bladder, and CNS adverse effects) and their use should be avoided when possible. In the elderly, anticholinergic agents should not be used as prophylaxis against extrapyramidal symptoms.
This medication is considered to be potentially inappropriate in this patient population (Beers Criteria: Parkinson's disease: Quality of evidence - moderate; Strength of recommendation - strong).
Dental Health: Effects on Dental Treatment
Key adverse event(s) related to dental treatment: Xerostomia and changes in salivation (normal salivary flow resumes upon discontinuation), dry throat, and nasal dryness (very prevalent).
Dental Health: Vasoconstrictor/Local Anesthetic Precautions
No information available to require special precautions
Mental Health: Comment
Along with diphenhydramine, benztropine is considered the drug of choice for patients with acute dystonic reactions. The usual adult dosage is I.M. 2 mg. In an emergency situation (laryngeal spasm), it should be given intravenously. Benztropine has a long duration of action and may be given once daily, preferable at bedtime due to possible sedation when used to treat pseudoparkinsonism and akathisia.
Dosage Forms
Excipient information presented when available (limited, particularly for generics); consult specific product labeling.
Injection, solution, as mesylate: 1 mg/mL
Cogentin®: 1 mg/mL
Tablet, oral, as mesylate: 0.5 mg, 1 mg, 2 mg
Pricing: U.S. (www.drugstore.com)
Tablets (Benztropine Mesylate)
0.5 mg (60): $15.99
1 mg (60): $15.99
2 mg (90): $22.99
References
"American Geriatrics Society Updated Beers Criteria for Potentially Inappropriate Medication Use in Older Adults," J Am Geriatr Soc, 2012 [epub ahead of print].
Duncan MA, Nikolov NM, and O'Kelly B, “Acute Chorea Due to Ondansetron in an Obstetric Patient,” Int J Obstet Anesth, 2001, 10(4):309-11.
Feinberg M, “The Problems of Anticholinergic Adverse Effects in Older Patients,” Drugs Aging, 1993, 3(4):335-48.
Falterman CG and Richardson CJ, "Small Left Colon Syndrome Associated With Maternal Ingestion of Psychotropic Drugs," J Pediatr, 1980, 97(2):308-10.
Harper G, Dawes M, Azlin C, et al, “Small Bowel Obstruction in a Child on an Antipsychotic,” J Child Adolesc Psychopharmacol, 1995, 5(1):81-4.
He H, McKay G, and Midha KK, “Phase I and II Metabolites of Benztropine in Rat Urine and Bile,” Xenobiotica, 1995, 25(8):857-72.
Lydon AM and Boylan JF, “Reversibility of Parkinsonism-Induced Acute Upper Airway Obstruction by Benztropine Therapy,” Anesth Analg, 1998, 87(4):975-6.
McEvoy JP, “The Clinical Use of Anticholinergic Drugs as Treatment for Extrapyramidal Side Effects of Neuroleptic Drugs,” J Clin Psychopharmacol, 1983, 3(5):288-302.
Roth A, Akyol S, and Nelson JC, “Delirium Associated With the Combination of a Neuroleptic, an SSRI, and Benztropine,” J Clin Psychiatry, 1994, 55(11):492-5.
Sachdev P and Loneragan C, “Intravenous Benztropine and Propranolol Challenges in Tardive Akathisia,” Psychopharmacology (Berl), 1993, 113 (1):119-22.
Schramm BM and Orser BA, “Dystonic Reaction to Propofol Attenuated by Benztropine (Cogentin),” Anesth Analg, 2002, 94(5):1237-40.
International Brand Names
Lexi-Comp.com
Last full review/revision March 2012
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