Overdose Toxic overdosage may result in confusion, restlessness, agitation, vomiting, hyperpyrexia, muscle rigidity, hyperactive reflexes, tachycardia, ECG evidence of impaired conduction, shock, congestive heart failure, stupor, coma, and CNS stimulation with convulsions followed by respiratory depression. Deaths have occurred following overdosage with drugs of this class. If you or someone you know may have used more than the recommended dose of this medicine, contact your local poison control center or emergency room immediately. No specific antidote is known. General supportive measures are indicated, with gastric lavage.
Respiratory assistance is apparently the most effective measure when indicated.
The use of CNS depressants may worsen the prognosis. The administration of barbiturates for control of convulsions alleviates an increase in the cardiac work load but should be undertaken with caution to avoid potentiation of respiratory depression. The value of dialysis has not been established. After you start using this medicine, several weeks may pass before you feel the full benefit. If your symptoms do not improve after taking this medicine for 4 weeks, inform your doctor.