Related Experiment Video
Updated: Aug 11, 2026

Assessing Changes in Volatile General Anesthetic Sensitivity of Mice after Local or Systemic Pharmacological Intervention
Published on: October 16, 2013
Possible interaction between imipramine and butalbital
K W Garey1, G W Amsden, C A Johns
1Clinical Pharmacology Research Center, and Department of Pharmacy, Bassett Healthcare, Cooperstown, New York 13326-1394, USA.
Abstract:
A 44-year-old woman was admitted to the psychiatric unit for exacerbation of her depressive disorder. Blood concentrations of her antidepressant, imipramine, were within normal range and consistent with past concentrations. Her medical history was significant for a chronic headache disorder for which she was given a prescription containing butalbital on admission. The patient's depressive disorder was quickly controlled but relapsed 2 weeks later. Concentrations of imipramine showed a decrease of approximately 50%. Imipramine is metabolized in the liver by the cytochrome P-450 (CYP 1A2) system, and barbiturates are known inducers of this enzyme subset. To our knowledge, an interaction specifically between butalbital and imipramine has not been documented; however, these drugs are extensively prescribed and occasions may arise where they are given concurrently. We recommend repeat measurement of imipramine concentrations 1 week after the start of any butalbital-containing product or barbiturate, and dosage adjustments based on the results and on the patient's response to the change.
Related Concept Videos
CNS Depressants: Barbiturates and Benzodiazepines
Anxiolytic Drugs: Benzodiazepines and Buspirone
Sedatives and Hypnotics Drugs: Barbiturates
Sedatives and Hypnotics Drugs: Miscellaneous Agents
Melatonin congeners like ramelteon (Rozerem) and tasimelteon (Hetlioz) selectively bind to melatonin receptors (MT1 and MT2) and thus mimic the actions of melatonin, a hormone that regulates sleep-wake cycles. Tasimelteon is primarily used for non-24-hour sleep-wake disorder, common in blind patients. They are also used to treat conditions like insomnia...
Pharmacokinetics: Drug–Drug Interactions
Drug toxicity: Drug–Drug Interaction

