Dual calcium-channel blocker therapy in the treatment of hypertension

Efficacy and safety of dual calcium channel blockade for the treatment of hypertension: a meta-analysis

BACKGROUND

Dual calcium-channel blocker (CCB) with a dihydropyridine (DHP) and a nondihydropyridine (NDHP) has been proposed for hypertension treatment. However, the safety and efficacy of this approach is not well known.

METHODS

A MEDLINE/EMBASE/CENTRAL search for randomized clinical trials published on this topic from 1966 to February 2012 was performed. Efficacy outcomes of decrease in systolic (SBP) and diastolic (DBP) blood pressures from baseline, changes in heart rate (HR), and adverse effects were compared between dual CCB therapy vs. DHP or NDHP. SBP, DBP, and HR were expressed as weighted mean deviation (WMD).

RESULTS

A total of 6 studies with 153 patients were included. Dual CCB produced a significantly greater reduction in SBP (21.6±9.2 mmHg) from baseline than DHP (10.3±6.3 mmHg (WMD = 10.9 mmHg, P < 0.0001)) or NDHP (8.9±4.2 mmHg (WMD = 14.1 mmHg, P = 0.002)). Dual CCB therapy reduced DBP from baseline more than either monotherapy (dual CCB = 17.5±10.2 mmHg vs. DHP = 11.6±8.7 mmHg, WMD = 5.5 mmHg, P < 0.001; and NDHP = 10.5±5.6 mmHg, WMD = 5.3 mmHg, P = 0.03). Dual CCB therapy had significantly lower HR compared to DHP (P < 0.001) but was comparable to NDHP (P = 0.12) (Delta change dual CCB = -4.0±3.5 vs. DHP = -2.0±1.5 and NDHP = -6.0±5.0 beats/min). Dual CCB therapy did not increase adverse effects.

CONCLUSIONS

Dual CCB therapy lowers blood pressure significantly better than CCB monotherapy, without an increase in adverse events. However, given the lack of long-term outcome data on efficacy and safety, dual CCB therapy should be used with restraint, if at all. Large-scale long-term trials are needed to further evaluate such a strategy.

Do calcium antagonists contribute to gastro-oesophageal reflux disease and concomitant noncardiac chest pain?

AIMS

A cohort retrospective observational study was undertaken to determine the relationship between calcium antagonist (CA) use and gastro-oesophageal reflux disease (GORD), as well the ability of CAs to precipitate or exacerbate noncardiac chest pain, an atypical symptom of GORD.

METHODS

Eligible patients were those prescribed CAs for hypertension without a history of ischaemic heart disease or nitrate use. Patients were recruited through 15 pharmacies (hospital 1, community 14). Patients giving informed consent were administered a standard questionnaire to obtain information including history of reflux symptoms before and during treatment with CAs, and the management of these symptoms.

RESULTS

Three hundred and seventy-one participants were enrolled. Their mean age was 64 years (SD +/- 12.7 years), 51.2% were females and 48.8% males. Of the 130 patients with pre-existing gastrointestinal (GI) symptoms, 59 (45.4%) reported a worsening of reflux symptoms during CA therapy. Increases in both frequency and severity of symptoms were most common amongst patients on amlodipine (61.3%; P <or= 0.0001) and least common amongst those taking diltiazem (12.5%). Reflux-related symptoms developed in 85 (35.3%) of the 241 previously asymptomatic patients during CA therapy, with verapamil having the greatest number of reports (39.1%; P = 0.001) and diltiazem the least (30.7%).

CONCLUSIONS

Diltiazem appears the least likely of the CAs to precipitate or exacerbate reflux symptoms. Further research using a prospective design could test whether it may be more appropriate to use diltiazem in patients with ischaemic heart disease and could assess the appropriateness of CA therapy in patients with moderate to severe GORD. Increasing prescriber and pharmacist awareness of these adverse effects may result in better patient outcomes and potentially reduce treatment costs.

Current concepts of pharmacotherapy in hypertension: combination calcium channel blocker therapy in the treatment of hypertension

Effective control of blood pressure is usually achieved only with the use of two or more antihypertensive medications. The treatment options for hypertension are numerous, and the number of possible combinations large. The selection of a specific combination drug regimen has often been linked to the perceived need for diuretic therapy as first- or second-step therapy; thus, the popularity of such drug combinations as an angiotensin-converting enzyme (ACE) inhibitor/diuretic, an angiotensin-receptor blocker/diuretic, or a beta blocker/diuretic. Rational alternatives exist, including an ACE inhibitor/calcium channel blocker (CCB) or a dihydropyridine CCB/b blocker combination. Traditionally, recommendations have advised against the use of combination therapy with two drugs from the same therapeutic class. However, because of the different binding and pharmacologic characteristics of CCBs, a rationale exists for combining different agents in this class in the management of hypertension and/or symptomatic coronary artery disease. In the treatment of either hypertension or angina, combination CCB therapy can prove uniquely successful.

Combination drug therapy in hypertension: a rational approach for the pharmacist

OBJECTIVE

To review the use of combination therapy versus monotherapy in hypertension, and to review seven major antihypertensive combinations in regard to their pharmacologic actions and appropriateness.

DATA SOURCES

Literature was identified through a MEDLINE search from January 1985 to December 1997. Search terms included hypertension, blood pressure, combination therapy, diuretics, beta-receptor antagonists, calcium channel antagonists, angiotensin-converting enzyme inhibitors (ACEIs). Major hypertension texts were also reviewed for information on combination therapy.

STUDY SELECTION

Clinical studies focusing primarily on blood pressure control with combinations of antihypertensive medications.

DATA EXTRACTION

Data were evaluated with respect to study design, clinical outcomes, and use of antihypertensive classes commonly seen in practice.

DATA SYNTHESIS

Combination therapy in hypertension is often required because many patients cannot be controlled on one drug alone. Available data demonstrate that ACEIs plus diuretics or calcium channel blockers (CCBs) produce synergistic effects on blood pressure. Beta-blockers plus diuretics or CCBs produce additive effects, as does the rarer combination of diltiazem plus a dihydropyridine CCB. Ineffective combinations include beta-blockers plus ACEIs and dihydropyridine CCBs plus diuretics, although there are specific clinical circumstances where these combinations may be used.

CONCLUSION

When used appropriately, certain combinations of antihypertensives can effectively control blood pressure and minimize side effects. The pharmacist who understands and applies the pharmacology of these antihypertensives can help prescribers make rational decisions in selecting combination therapy.