Imipramine should be used with caution in hyperthyroid patients or those on thyroid medication because of the possibility of cardiovascular toxicity. Patients with a history of seizure disorder should be cautious because this drug has been shown to lower the seizure threshold. Patients receiving guanethidine, clonidine, or similar agents, need to be watched since imipramine may block the pharmacologic effects of these drugs. Imipramine may produce urinary retention and should be used with caution in patients with urinary pathology , particularly in the presence of prostatic hypertrophy. Therefore, it should be kept in mind that the dangers inherent in a suicide attempt of accidental overdosage with the drug may be increased for the patient who uses excessive amounts of alcohol.
Sulfite sensitivity is seen more frequently in asthmatic than in nonasthmatic people.
Elderly patients and patients with cardiac disease or a prior history of cardiac disease are at special risk of developing the cardiac abnormalities associated with the use of imipramine. It should be kept in mind that the possibility of suicide in seriously depressed patients is inherent in the illness and may persist until significant remission occurs. Such patients should be carefully supervised during the early phase of treatment with imipramine, and may require hospitalization. Prescriptions should be written for the smallest amount feasible. Hypomanic or manic episodes may occur, particularly in patients with cyclic disorders.