Some drugs that are administered via the oral route undergo extensive first-pass metabolism before reaching the systemic circulation. This first-pass metabolism can occur in the gut and the liver.
Image showing a schematic diagram of first-pass metabolism
Listed below are some drugs that undergo extensive first-pass metabolism:
- Atorvastatin
- Budesonide
- Buspirone
- Chlorpromazine
- Clomethiazole
- Felodipine
- Hydralazine (rate of metabolism is dependent upon the acetylator status of the individual)
- Isosorbide dinitrate
- Labetalol
- Methylphenidate
- Morphine
- Nimodipine
- Oxprenolol
- Pentazocine
- Pethidine
- Propafenone
- Propranolol
- Raloxifene
- Salbutamol (the inhaled dose that is swallowed undergoes significant first-pass metabolism)
- Simvastatin
- Verapamil