Monday Pharmaceutical Mystery: January 21

You are a retail pharmacist, and you get a phone call from a doctor's office with a new prescription to treat an H pylori infection. The order is for tetracycline, bismuth, metronidazole, and pantoprazole. The doctor asks several questions about prior antibiotic orders. The patient has failed H pylori therapy in the past, and the doctor is concerned about the possibility of antibiotic resistance.

It comes to your attention that the patient recently had similar orders filled for clarithromycin, metronidazole, and pantoprazole—3 months ago and again 5 months ago. There have been no other antibiotics prescribed, and the patient does not have any drug allergies. The patient is male, aged 45 years and the only diagnosis on file is cirrhosis of the liver secondary to ongoing alcoholism.

Mystery: Why is this patient getting so many prescriptions for H pylori? Antimicrobial resistance rates for clarithromycin resistance are generally assumed to be ≥15% unless local data indicate otherwise.

You double check all the dosages, and the regimens are correct for the patient's height, weight and normal renal function.

Solution: The patient is noncompliant due to the metronidazole, alcohol-disulfiram interaction. It would be better for this patient if the order was switched to the clarithromycin, amoxicillin and pantoprazole regimen.

Reference

Duck WM, Sobel J, Pruckler JM, et al. Antimicrobial resistance incidence and risk factors among Helicobacter pylori-infected persons, United States. Emerg Infect Dis. 2004;10(6):1088-94. www.ncbi.nlm.nih.gov/pubmed?term=15207062&rel=0" Accessed January 21, 2019