Muscarinic Blocking Drugs: Contraindications and Cautions

CONTRAINDICATIONS AND CAUTIONS

Muscarinic blocking agents are contraindicated in angle-closure glaucoma. Caution also should be used in individuals with untreated open-angle glaucoma, car-diac disease, hyperthyroidism, or prostatic hypertrophy. Muscarinic antagonists can aggravate reflux esophagitis by decreasing the tone of the lower esophageal sphinc-ter. Infants and children are especially sensitive to the hyperthermic action of muscarinic blockers. Elderly pa-tients are especially sensitive to antimuscarinic effects in the CNS, such as impairment of memory. Pheno-thiazines and tricyclic antidepressants have antimus-carinic activity and can produce effects that are additive to those of the muscarinic blocking drugs. Anti-muscarinics should not be given to patients with gas-trointestinal infections because the drug will slow gas-tric motility and cause the patient to retain the infectious organisms in the gastrointestinal tract.