Cimetidine-induced alterations in desipramine plasma concentrations

Area of Science:

• Pharmacology
• Clinical Pharmacy
• Drug Interactions

Background:

• Desipramine is a tricyclic antidepressant used for depression.
• Cimetidine is a medication that can inhibit drug metabolism.
• Drug interactions between antidepressants and other medications require careful consideration.

Purpose of the Study:

• To investigate the effect of cimetidine on desipramine plasma levels.
• To assess the impact of cimetidine on the metabolism of desipramine.

Main Methods:

• Eight patients on maintenance desipramine doses were given cimetidine for four days.
• Plasma levels of desipramine and its metabolite 2-hydroxydesipramine were measured.

Main Results:

• Concurrent cimetidine administration significantly elevated desipramine plasma levels by a mean of 51%.
• Plasma levels of the metabolite 2-hydroxydesipramine also increased significantly by a mean of 46%.
• Statistical analysis showed P < 0.001 for both elevations.

Conclusions:

• Cimetidine significantly increases plasma concentrations of desipramine and its primary metabolite.
• These findings suggest that therapeutic drug monitoring of desipramine may be warranted in patients also receiving cimetidine.
• Clinicians should be aware of this potential drug interaction when prescribing these medications concurrently.