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As in any case of overdose, general supportive measures should be utilized. Overdosage with cholinesterase inhibitors can cause a cholinergic crisis characterized by severe nausea/vomiting, salivation, sweating, bradycardia, hypotension, collapse, and convulsions. Increasing muscle weakness is a possibility and may result in death if respiratory muscles are involved.

Tertiary anticholinergics such as atropine may be used as an antidote for Cognex® (tacrine) overdosage. Intravenous atropine sulfate titrated to effect is recommended: in adults, nitial dose of 1.0 to 2.0 mg IV with subsequent doses based on clinical response. In children, the usual IM or IV dose is 0.05 mg/kg, repeated every 10-30 minutes until muscarinic signs and symptoms subside and repeated if they reappear. Atypical increases in blood pressure and heart rate have been reported with other cholinomimetics when coadministered with quaternary anticholinergics such as glycopyrrolate.

It is not known whether Cognex® (tacrine) or its metabolites can be eliminated by dialysis (hemodialysis, peritoneal dialysis, or hemofiltration).

The estimated median lethal dose of tacrine following a single oral dose in rats is 40 mg/kg, or approximately 12 times the maximum recommended human dose of 160 mg/day. Dose-related signs of cholinergic stimulation were observed in animals and included vomiting, diarrhea, salivation, lacrimation, ataxia, convulsions, tremor, and stereotypic head and body movements.


Cognex® (tacrine) is contraindicated in patients with known hypersensitivity to tacrine or acridine derivatives.

Cognex® (tacrine) is contraindicated in patients previously treated with Cognex® (tacrine) who developed treatment-associated jaundice; a serum bilirubin > 3 mg/dL; and/or those exhibiting clinical signs or symptoms of hypersensitivity (eg, rash or fever) in association with ALT/SGPT elevations.

This monograph has been modified to include the generic and brand name in many instances.

Last reviewed on RxList: 6/24/2008


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You are encouraged to report negative side effects of prescription drugs to the FDA. Visit the FDA MedWatch website or call 1-800-FDA-1088.

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