Pharmacological class Drug* Impaired metabolism CYP Antihypertensives nifedipine, felodipine, diltiazem propranolol irbesartan verapamil yes no no yes 3A4/3A5 2D6 2C9 several Antiarrhythmics amiodarone, lidocaine yes 3A4/3A5 Anxiolytics/hypnotics   triazolam, zolpidem diazepam midazolam yes no no 3A4/3A5 3A4/3A5 3A4 Antidepressants   amitriptyline sertraline fluoxetine, nortriptyline, venlafaxine citalopram imipramine yes no no no yes 3A4/3A5 3A4/3A5 2D6 2C9 2C19 Anticonvulsants carbamazepine phenytoin yes no 3A4/3A5 2C9 Antipsychotics risperidone no 2D6 Analgesics (opioids) fentanyl alfentanil yes no 3A4/3A5 3A4/3A5 NSAIDs paracetamol naproxen celecoxib, diclofenac ibuprofen no yes no no 3A4/3A5 2C9 2C9 several Antibiotics cyclosporine yes 3A4/3A5 Anticoagulants warfarin yes 2C9 * When the drug belongs to two or more pharmacological classes, it is presented in only one class CYP – cytochrome P450; NSAIDs – Non-steroidal anti-inflammatory drugs

Table 2: Phase I drug biotransformation characteristics in the elderly (modified from Turnheim [12]).