Nearly 65% of hypertensive patients are uncontrolled on their current blood pressure medication, and most patients will require
two or more drugs to reach their blood pressure goal. Consistent with the necessity of a polypharmacy approach to treatment
of hypertension, a report released earlier this year by the market research firm Decision Resources found that more than half
of physicians prefer two drugs combined in a single pill when prescribing medication for treatment of cardiovascular diseases.
Combination approach
To meet the demand for the combination approach, Azor (amlodipine/olmesartan medoxomil, Daiichi Sankyo) was recently approved
by the Food & Drug Administration as a once-daily oral tablet containing both a calcium-channel blocker and an angiotensin
receptor blocker. As a calcium-channel blocker, amlodipine reduces total peripheral vascular resistance by preventing calcium
entry into blood vessel walls. Olmesartan medoxomil keeps angiotensin II, a potent endogenous vasoconstrictor, from binding
to its receptor. Together, the two medications relax blood vessels to lower blood pressure.
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In clinical trials, Azor 10/40 mg reduced systolic blood pressure an average of 30.1 mm Hg and diastolic pressure by an average
of 19.0 mm Hg. In comparison with amlodipine 10 mg monotherapy, Azor 10/40 mg provided a 53% greater reduction in mean change
of systolic blood pressure. Previous clinical trials using similar combination products (amlodipine/valsartan; Exforge; Novartis)
have also demonstrated statistically significant mean reductions in blood pressure when compared with monotherapy. Maximal
antihypertensive effects can be anticipated within two weeks of initiating Azor or increasing Azor doses.
Azor is approved for use alone or as an add-on therapy for patients not adequately controlled on other antihypertensive agents,
but it is not intended to be used as initial therapy. Tablets are available in four strengths (amlodipine/olmesartan medoxomil):
5/20 mg, 10/20 mg, 5/40 mg, and 10/40 mg.
Clinical studies
During clinical studies only edema occurred in >3% of patients treated with Azor and more frequently than placebo (22.1% versus
12.3%); edema is a known dose-dependent side effect of amlodipine. Significantly, African Americans (a population more likely
to develop hypertension than any other racial or ethnic group) comprised 25% of the studied population, and the magnitude
of blood pressure reduction was similar in both African Americans and non-African Americans.
As with other drugs that contain angiotensin receptor blockers, Azor should be avoided during pregnancy due to the risk of
injury and death to the developing fetus. Increases in serum creatinine or blood urea nitrogen can be anticipated in individuals
with renal artery stenosis.
In general, calcium-channel blockers should be used cautiously in patients with heart failure. Due to the risk of symptomatic
hypotension, close medical supervision is suggested when initiating Azor in volume-depleted or sodium-depleted patients. Overall,
no differences in safety or efficacy were observed between subjects ≥ 65 years of age and younger subjects.
When asked how Azor will likely fit into current clinical practice, Amy Seybert, Pharm.D., assistant professor of pharmacy
and therapeutics at University of Pittsburgh School of Pharmacy and clinical cardiology pharmacist, commented, "It depends
on the physician and patient comfort level.... Start with samples and reevaluate the drug therapy at a later point in time."
She believes that the difficulty in attaining blood pressure goals is due to several things. "Patient unawareness, insurance
coverage, and a disease that does not show any symptoms are all factors in treatment failure."
TIPS TO REMEMBER Azor
- Azor combines the calcium-channel blocker amlodipine with the angiotensin receptor blocker olmesartan medoxomil.
- Azor should not be used as initial therapy for treating hypertension.
- Tablets are available in four strengths (amlodipine/ olmesartan medoxomil): 5/20 mg, 10/20 mg, 5/40 mg, and 10/40 mg.
THE AUTHOR is a clinical writer based in the Philadelphia area.
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