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]).