Benzatropine Mesilate

(BANM, rINNM)
Benzatropine Mesilate Chemical formula
Synonyms: Benzatropine, Mésilate de; Benzatropine Methanesulfonate; Benzatropini Mesilas; Benztropine Mesylate; Mesilato de benzatropina. (1R,3r,5S)-3-Benzhydryloxytropane methanesulphonate.
Cyrillic synonym: Бензатропина Мезилат.

💊 Chemical information

Chemical formula: C21H25NO,CH4O3S = 403.5.
CAS — 86-13-5 (benzatropine); 132-17-2 (benzatropine mesilate).
ATC — N04AC01.
ATC Vet — QN04AC01.

Pharmacopoeias.

In Br. and US.

BP 2008

(Benzatropine Mesilate). A white, odourless or almost odourless, crystalline powder. Very soluble in water; freely soluble in alcohol; practically insoluble in ether.

USP 31

(Benztropine Mesylate). A white, slightly hygroscopic, crystalline powder. Very soluble in water; freely soluble in alcohol; very slightly soluble in ether. Store in airtight containers.

💊 Adverse Effects, Treatment, and Precautions

As for Atropine Sulfate. Drowsiness may be severe in some patients and patients so affected should not drive or operate machinery. Mental disturbances and excitement may occur with large doses or in susceptible patients.

Abuse.

For mention of abuse of benzatropine see under Trihexyphenidyl Hydrochloride.

Effects on the heart.

Paradoxical sinus bradycardia in a patient with depression and psychotic symptoms was attributed to benzatropine since it persisted despite modification to other treatment and resolved only when benzatropine was withdrawn.1
1. Voinov H, et al. Sinus bradycardia related to the use of benztropine mesylate. Am J Psychiatry 1992; 149: 711.

💊 Interactions

As for antimuscarinics in general.

Antidepressants.

A report1 of 5 patients who developed delirium while taking an antipsychotic, an SSRI, and benzatropine suggested that there might be an interaction between SSRIs and benzatropine.
1. Roth A, et al. Delirium associated with the combination of a neuroleptic, an SSRI, and benztropine. J Clin Psychiatry 1994; 55: 492–5.

Antipsychotics.

Fatal heat stroke after exposure to an ambient temperature of over 29° has been reported1,2 in patients receiving benzatropine with antipsychotics. Paralytic ileus, sometimes fatal, has also been seen in patients taking benzatropine with antipsychotics.3
1. Stadnyk AN, Glezos JD. Drug-induced heat stroke. Can Med Assoc J 1983; 128: 957–9
2. Tyndel F, Labonté R. Drug-facilitated heat stroke. Can Med Assoc J 1983; 129: 680
3. Wade LC, Ellenor GL. Combination mesoridazine- and benztropine mesylate-induced paralytic ileus: two case reports. Drug Intell Clin Pharm 1980; 14: 17–22.

💊 Uses and Administration

Benzatropine mesilate is a tertiary amine antimuscarinic with actions and uses similar to those of trihexyphenidyl; it also has antihistaminic properties. Benzatropine is used for the symptomatic treatment of parkinsonism, including the alleviation of the extrapyramidal syndrome induced by drugs such as phenothiazines, but, like other antimuscarinics, is of no value against tardive dyskinesias. It has been used in the treatment of dystonias. Benzatropine mesilate is given orally or, if necessary, by intramuscular or intravenous injection. In idiopathic parkinsonism benzatropine mesilate is usually given orally in an initial daily dose of 0.5 to 1 mg at bedtime. Its actions are cumulative, and may not be manifest for several days after beginning therapy. Patients with post-encephalitic parkinsonism often tolerate an initial daily dose of 2 mg. The dose may be gradually increased by 500 micrograms every 5 to 6 days to a maximum of 6 mg daily until the optimum dose is reached. Maintenance therapy may be given as a single daily dose at bedtime or in divided doses 2 to 4 times daily. In the management of drug-induced extrapyramidal symptoms doses of 1 to 4 mg once or twice daily have been given orally or parenterally. Therapy may be withdrawn after 1 to 2 weeks to assess whether it is still necessary. In an emergency, benzatropine mesilate may be injected intramuscularly or intravenously in a dose of 1 to 2 mg; intramuscular injection is reported to produce an effect as quickly as intravenous dosage so the latter is rarely necessary. For management of dystonias in children, the BNFC suggests that in an emergency, single doses of 20 to 100 micrograms/kg (maximum of 2 mg) may be given by intravenous or intramuscular injection to children aged 3 to 12 years, and 1 to 2 mg to those aged 12 to 18 years. Benzatropine has also been given as the hydrochloride.

💊 Preparations

BP 2008: Benzatropine Injection; Benzatropine Tablets; USP 31: Benztropine Mesylate Injection; Benztropine Mesylate Tablets.

Proprietary Preparations

Austral.: Benztrop; Cogentin; Austria: Cogentin; Canad.: Cogentin†; Cz.: Apo-Benztropine; Denm.: Cogentin†; Hong Kong: Cogentin; Irl.: Cogentin†; Norw.: Cogentin†; NZ: Benztrop; Cogentin; Port.: Cogentin†; Thai.: Cogentin; UK: Cogentin; USA: Cogentin.
Published October 19, 2018.