Use in the Elderly Older adults may be more susceptible to the side effects of protriptyline. If they use the drug, it is usually at reduced dosages, as described above. Drug Interactions Protriptyline may interfere with the effect of blood-pressure medications such as guanethidine or clonidine. Taking protriptyline and thyroid drugs together may intensify the effects of both drugs. Oral contraceptives and cigarette smoking may decrease the effect of protriptyline.
Estrogens can increase or decrease the effect of protriptyline.
Bicarbonate of soda, acetazolamide, quinidine, and procainamide may increase the effect of protriptyline. Protriptyline may increase the effect of other central nervous system depressants including alcohol, sleeping pills, narcotic pain relievers, tranquilizers, barbiturates, and antihistamines. Food Interactions Protriptyline may be taken with or without food. The appropriate choice varies from person to person and depends on age, physical health and condition, and other drugs being concurrently used. Desipramine is often the first choice among tricyclic antidepressants because it is effective and has relatively few side effects in most people.