Grapefruit juice and verapamil: a toxic cocktail.
The US public consumes grapefruit juice in large quantities, with 14% of the population drinking the juice at least weekly. Grapefruit juice is a well-documented inhibitor of the CYP3A4 isoenzyme, which is involved in the metabolism of over 50% of commonly prescribed drugs. Here we report an unusual case of verapamil toxicity in a 42-year-old female, which resulted from accidental ingestion of only three tablets of the sustained release preparation (120 mg each) over 24 hours which resulted in severe toxicity.
Pillai
Unnikrishnan
U
Internal Medicine and the Medical Clinic, St. Mary's Health Center, St. Louis, MO 63117, USA. unnikrishnanpk@yahoo.com
Muzaffar
Jameel
J
Sen
Sandeep
S
Yancey
Abigail
A
D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000187:drug effects / Q000378:metabolism; D000328:Adult; D002121:Calcium Channel Blockers / Q000493:pharmacokinetics / Q000506:poisoning*; D032083:Citrus paradisi / Q000009:adverse effects*; D051544:Cytochrome P-450 CYP3A / Q000187:drug effects / Q000378:metabolism*; D004347:Drug Interactions; D062787:Drug Overdose; D005260:Female; D006801:Humans; D012121:Respiration, Artificial; D014700:Verapamil / Q000493:pharmacokinetics / Q000506:poisoning*
D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D002121:Calcium Channel Blockers; D014700:Verapamil; D051544:Cytochrome P-450 CYP3A; C510163:CYP3A4 protein, human