Selecting an appropriate medication for treating neuropathic pain in patients with diabetes: A study using the U.K. and Germany mediplus databases

Objective: To evaluate the appropriateness of prescribing select neuropathic pain medications to diabetes patients based on the potential for drug-drug interactions with medications diabetes patients were prescribed continuously for ≥3 months (chronic use). Methods: Medical records of patients with a diagnosis of diabetes or use of antidiabetic medications between January 1, 2002 and September 30, 2005 in the U.K. and Germany Mediplus databases were obtained. Patients: Medication use profiles were evaluated between April 2004 and September 2005. The metabolic pathways associated with medications that were prescribed chronically to at least 10% of study patients were compared with the metabolic pathways of neuropathic pain medications to identify potential drug-drug interactions. Results: A total of 40,448 patients in the U.K. (63.6±16.6years, 51% male) and 31,930 patients in Germany (68.9±12.7years, 46% male) were identified. Frequently prescribed medications in the U.K. included aspirin (33.7%), metformin (32.7%), simvastatin (25.5%), atorvastatin (19.4%), atenolol (18.1%), and in Germany hydrochlorothiazide (35.8%), aspirin (25.2%), metformin (21.6%), metoprolol (20.3%), and simvastatin (18.3%). Several neuropathic pain medications have potential for drug-drug interactions with medications prescribed to diabetes patients. Examples include (neuropathic pain medications vs. diabetes medications): duloxetine, paroxetine, and methadone (CYP2D6 inhibitors) and oxycodone HCL, hydrocodone (CYP2D6 substrates) vs. metoprolol and bisoprolol (CYP2D6 substrates); and carbamazepine (CYP3A4 inducer) vs. simvastatin, and atorvastatin (CYP3A4 substrates). Conclusions/Interpretation: Our findings underscore the need for medical vigilance when selecting medications for treating neuropathic pain in diabetes patients.