Caution if cardiac irregularities or cholinergic effects develop (overdosage may result in cholinergic crisis). May depress plasma and erythrocyte cholinesterase levels after a few weeks of therapy. Not generally recommended for use in the following cases: asthma, bradycardia, hypotension or recent MI, GI disease (including peptic ulcer disease), parkinsonism, history of seizure disorder, or vagotonia. Avoid use for tonometric glaucoma, or with active or history of uveitis, or retinal detachment. Use cautiously prior to ophthalmic surgery due to risk of blood in the anterior chamber. Use caution in patients on concomitant anticholinesterase agents (possible additive effects if chronically exposed to organophosphate/carbamate pesticides/insecticides). If general anesthesia required, use succinylcholine with great caution due to potential for respiratory or cardiovascular collapse. Tolerance may be developed (after prolonged use).