A Cost Analysis of Switching Calcium Channel Blockers

In: Main

1 Jul 2010

Switching CalciumEffective management of patients with hypertension is a health care priority because of the increased risk for cardiovascular morbidity and mortality associated with this disease and the significant economic burden that results if it is left untreated. The American Heart Association (AHA) has estimated the annual total cost of cardiovascular disease and stroke to be $326.6 billion.

Many studies, including the sixth report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of Hypertension (JNCVI), support the position that drugs from many different classes are suitable as initial therapy for patients with hypertension. The newer long-acting dihydropyridine (DHP) calcium channel blockers (CCBs) have been shown to be highly effective and well-tolerated in a wide range of patients with hypertension or angina. These drugs provide smooth 24-hour control over blood pressure with once-daily dosing and without excess activation of the sympathetic nervous system.

The cost of blood pressure-lowering medication for patients with hypertension is a significant component of the overall cost of treating hypertension and its associated risks. Results from a recent review indicated that the total cost of drugs used to treat hypertension in the U.S. in 1995 was $8.3 billion. The cost for CCBs alone was $2.86 billion.12 Drug acquisition costs are cited by managed care organizations as one of the major reasons for rate increases, and concern about the expense of antihypertensive drugs has prompted attempts to control their cost through formulary management. Some organizations switch patients from one CCB to another to reduce drug acquisition expenses. Although cost savings resulting from such a switch can be estimated from expected dosages and established drug prices, the true cost of treatment can also be strongly influenced by higher-than-anticipated drug doses, reduced or increased requirements for additional blood pressure-lowering medications, laboratory tests, and office visits for the management of adverse events and/or dose titration. It is therefore important to review actual changes in treatment cost associated with switching patients from one antihypertensive agent to another.

For example, at Barksdale Air Force Base in Louisiana, a switch from amlodipine to extended-release (felodipine ER), motivated by a slight difference in drug acquisition cost, resulted in an increase in overall drug costs for control of blood pressure rather than the expected decrease, because of the need for higher-than-expected felodipine doses and additional antihypertensive medications. In another study, Zotto and associates evaluated the effects of converting patients from nifedipine gastrointestinal therapeutic system (GITS) to at Patrick Air Force Base in Florida. GITS is another slow-release formulation of this CCB. Zotto et al.’s review included the records of 1,245 patients. At six months after the switch, 99% (1,233/1,245) of the switched patients remained on amlodipine and 80.5% were maintained at a dose of 5 mg/day or less. For the 1,233 patients who remained on amlodipine, the switch in therapy resulted in an annual savings of more than $106,000 in dihydropyridine acquisition costs alone. In addition, 213 patients who had required one or more concomitant antihypertensive drugs while receiving nifedip-ine GITS were managed with amlodipine monotherapy, further reducing the total cost of blood pressure-lowering therapy. Conversion to amlodipine canadian provided good control of blood pressure and also increased patient satisfaction with therapy.

The present study was undertaken to evaluate changes in the cost of antihypertensive therapy associated with switching patients from amlodipine to either felodipine canadian extended-release (ER) or nifedipine drug core coat (CC).

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