Drug Interaction Study of Olmesartan in Healthy Chinese Volunteers

Overview

Hypertension and hyperuricaemia are widespread conditions. There is significant overlap between the two conditions. Serum uric acid (SUA) is currently recognized as a risk factor for cardiovascular disease. Thus, at some point in their therapy, hypertensive patients with hyperuricaemia are likely to require concurrent treatment with anti-hypertensive and hypouricaemic agents. For this reason, it is important to determine whether there are any pharmacokinetic interactions resulting from the concomitant administration of such agents.Olmesartan is an angiotensin II receptor antagonist and effective and well tolerated in the treatment of arterial hypertension. Probenecid is a well-established hypouricaemic agent for the treatment of hyperuricaemia and gout.The goal of this study was to examine the impact of coadministration of probenecid on the pharmacokinetic parameters and tolerability of olmesartan in healthy volunteers.

Probenecid is a well-established hypouricaemic agent for the treatment of hyperuricaemia and gout and is thought to act on urate transporter 1 (URAT1), a novel member of the organic anion transporter (OAT) family, thereby increasing uric acid excretion in the kidney by blocking urate reuptake, and then, resulting in a decrease of SUA. Olmesartan is an angiotensin II receptor antagonist and effective and well tolerated in the treatment of arterial hypertension. Olmesartan is orally administered in the prodrug form, olmesartan medoxomil, which is converted to the pharmacologically-active compound olmesartan upon de-esterification by the enzyme arylesterase in the intestinal wall, portal blood, and liver. Olmesartan is excreted by hepatobiliary and renal systems without further metabolism, and its pharmacokinetic profile is not affected by age or gender. In addition, the pharmacokinetic and pharmacodynamic profile of olmesartan is favorable, both in terms of providing effective 24-hour blood pressure (BP) control with once-daily dosing, and in restricting the likelihood of pharmacokinetic interactions with other drugs. Studies in vitro show organic anion transporting polypeptide 1B1 (OATP1B1), OATP1B3, multidrug resistance-associated protein 2 (MRP 2), and breast cancer resistance protein (BCRP) are involved in hepatobiliary and renal transport of olmesartan. We know probenecid interferes with the kidneys' organic anion transporter (OAT). Will probenecid have effects on the pharmacokinetics of olmesartan thereby result in changes of antihypertensive effect and side effects of olmesartan? Until now, many clinical studies have shown olmesartan has no pharmacokinetic interactions with other drugs; moreover, there is no research about the interactions between olmesartan and probenecid. In this study, we assess the involvement of probenecid in the pharmacokinetics and tolerability of olmesartan.