ADVERSE REACTIONS. The adverse reactions below, most of which are anticholinergic in nature, have been reported and within each category are listed in order of decreasing severity.Cardiovascular: Tachycardia. Digestive: Paralytic ileus, constipation, vomiting, nausea, dry mouth.If dry mouth is so severe that there is difficulty in swallowing or speaking, or loss of appetite and weight, reduce dosage, or discontinue the drug temporarily. Slight reduction in dosage may control nausea and still give sufficient relief of symptoms. Vomiting may be controlled by temporary discontinuation, followed by resumption at lower dosage. Nervous System: Toxic psychosis, including confusion, disorientation, memory impairment, visual hallucinations; exacerbation of pre-existing psychotic symptoms; nervousness; depression; listlessness; numbness of fingers. Special Senses: Blurred vision, dilated pupils. Urogenital: Urinary retention, dysuria. Metabolic/Immune or Skin: Occasionally, an allergic reaction, e.g., skin rash, develops. If this cannot be controlled by dosage reduction, the medication should be discontinued. Other: Heat stroke, hyperthermia, fever.


CLINICAL PHARMACOLOGY. Benztropine mesylate possesses both anticholinergic and antihistaminic effects, although only the former have been established as therapeutically significant in the management of parkinsonism. In the isolated guinea pig ileum, the anticholinergic activity of this drug is about equal to that of atropine; however, when administered orally to unanesthetized cats, it is only about half as active as atropine. In laboratory animals, it antihistaminic activity and duration of action approach those of pyrilamine maleate.


CONTRAINDICATIONS. Hypersensitivity to any component of benztropine mesylate injection.Because of its atropine-like side effects, this drug is contraindicated in pediatric patients under three years of age, and should be used with caution in older pediatric patients.


DESCRIPTION. Benztropine mesylate is synthetic compound containing structural features found in atropine and diphenhydramine. It is designated chemically as 8-azabicyclo[3.2.1] octane, 3-(diphenylmethoxy)-, endo, methanesulfonate. Its empirical formula is C21H25NOoCH4O3S, and its structural formula is: Benztropine mesylate is crystalline white powder, very soluble in water, and has molecular weight of 403.54.Benztropine mesylate Injection is supplied as sterile injection for intravenous and intramuscular use.Each milliliter of the injection contains: Benztropine mesylate mg/mL Sodium chloride mg/mL Water for injection q.s. mL. Chemical Structure.


DOSAGE AND ADMINISTRATION. Since there is no significant difference in onset of effect after intravenous or intramuscular injection, usually there is no need to use the intravenous route. The drug is quickly effective after either route, with improvement sometimes noticeable few minutes after injection. In emergency situations, when the condition of the patient is alarming, to mL of the injection normally will provide quick relief. If the parkinsonian effect begins to return, the dose can be repeated.Because of cumulative action, therapy should be initiated with low dose which is increased gradually at five or six-day intervals to the smallest amount necessary for optimal relief. Increases should be made in increments of 0.5 mg, to maximum of mg, or until optimal results are obtained without excessive adverse reactions.


HOW SUPPLIED. Injection benztropine mesylate, mg per mL, is clear, colorless solution and is supplied in boxes of x mL vials.Store at 25C (77F): excursions permitted to 15 to 30C (59 to 86F) [see USP Controlled room temperature], protect from light, retain in carton until time of use.NDC Number 14789-300-02Manufactured in the USA for: Nexus Pharmaceuticals, Inc., Lincolnshire, IL 60069 May 2009 PM-301001Duvoisin, R.C.; Katz, R.J.; Amer. Med. Ass. 206:1963-1965, Nov.25, 1968Registered trademark of MERCK CO., Inc.


INDICATIONS AND USAGE. For use as an adjunct in the therapy of all forms of parkinsonism.Useful also in the control of extrapyramidal disorders (except tardive dyskinesia --- see PRECAUTIONS) due to neuroleptic drugs (e.g., phenothiazines).


OVERDOSAGE. Manifestations: May be any of those seen in atropine poisoning or antihistamine overdosage: CNS depression, preceded or followed by stimulation; confusion; nervousness; listlessness; intensification of mental symptoms or toxic psychosis in patients with mental illness being treated with neuroleptic drugs (e.g., phenothiazines); hallucinations (especially visual); dizziness; muscle weakness; ataxia; dry mouth; mydriasis; blurred vision; palpitations; tachycardia; elevated blood pressure; nausea; vomiting; dysuria; numbness of fingers; dysphagia; allergic reactions, e.g., skin rash; headache; hot, dry, flushed skin; delirium; coma; shock; convulsions; respiratory arrest; anhidrosis; hyperthermia; glaucoma; constipation.Treatment: Physostigmine salicylate, to mg, SC or IV, reportedly will reverse symptoms of anticholinergic intoxication1. second injection may be given after hours if required. Otherwise treatment is symptomatic and supportive. Induce emesis or perform gastric lavage (contraindicated in precomatose, convulsive, or psychotic states). Maintain respiration. short-acting barbiturate may be used for CNS exctextent, but with caution to avoid subsequent depression; supportive care for depression (avoid convulsant stimulants such as picrotoxin, pentylenetetrazol, or bemegride); artificial respiration for severe respiratory depression; local miotic for mydriasis and cycloplegia; ice bags or other cold applications and alcohol sponges for hyperpyrexia, vasopressor and fluids for circulatory collapse. Darken room for photophobia.


PACKAGE LABEL PRINCIPAL DISPLAY PANEL BOX OF 5x2 mL VIALS. NDC 14789-300-02Benztropine Mesylate Injection, USP2 mg/2mL (1 mg/ mL)FOR INTRAVENOUS OR INTRAMUSCULAR USERx only. PACKAGE LABEL Box of 5x2 mL vials.




WARNINGS. Safe use in pregnancy has not been established. Benztropine mesylate may impair mental and/or physical abilities required for performance of hazardous tasks, such as operating machinery or driving motor vehicle.When benztropine mesylate is given concomitantly with phenothiazines, haloperidol, or other drugs with anticholinergic or anti-dopaminergic activity, patients should be advised to report gastrointestinal complaints, fever or heat intolerance promptly. Paralytic ileus, hyperthermia and heat stroke, all of which have sometimes been fatal, have occurred in patients taking anti-cholinergic-type antiparkinsonism drugs, including benztropine mesylate, in combination with phenothiazines and/or tricyclic antidepressants.Since benztropine mesylate contains structural features of atropine, it may produce anhidrosis. For this reason, it should be administered with caution during hot weather, especially when given concomitantly with other atropine-like drugs to the chronically ill, the alcoholic, those who have central nervous system disease, and those who do manual labor in hot environment. Anhidrosis may occur more readily when some disturbance of sweating already exists. If there is evidence of anhidrosis, the possibility of hyperthermia should be considered. Dosage should be decreased at the discretion of the physician so that the ability to maintain body heat equilibrium by perspiration is not impaired. Severe andhidrosis and fatal hyperthermia have occurred.