Valsartan is eliminated mainly as unchanged drug. A small portion of the drug is metabolized by CYP 2C9, and some weak inhibitory potential is observed in vitro. No clinically significant effects on CYP is expected or observed in clinical studies.

Angiotensin II receptor antagonist.

Valsartan is used in the treatment of essential hypertension. It is administered orally.

About 80 per cent of administered dose of valsartan is excreted in unchanged form. A small portion of the drug is metabolized by CYP 2C9 to the inactive metabolite 4-OH-valsartan (Nakashima 2005, SPC). It has a half- life of about 5-9 hours (drugbank). Valsartan has been shown not to inhibit human cytochrome P450 enzymes CYP1A, 2A6, 2C19, 2D6, 2E and 3A in vitro in concentrations up to 100µM. A weak and clinically insignificant inhibition of CYP 2C9 was seen (Taavitsainen 2000). In an in vivo study, no drug-drug interaction was observed upon co-administration of Valsartan/sacubitril with digoxin/warfarin in healthy subjects (Ayalasomayajula).

Uneventful use reported in 15 patients with acute porphyria.