Headaches and the Treatment of Blood Pressure

Abstract

Background-Uncertainty exists over whether blood pressure-lowering drugs prevent headache. Methods and Results-A meta-analysis was carried out of the 94 randomized placebo-controlled trials of 4 different classes of blood pressure-lowering drugs (thiazides, ␤-blockers, ACE inhibitors, and angiotensin II receptor antagonists) in fixed doses in which data on headache were reported. There were 17 641 participants who were allocated blood pressure-lowering drugs and 6603 who were allocated placebo. Treatment lowered systolic and diastolic blood pressures by 9.4 and 5.5 mm Hg, respectively, on average. One third fewer people on average reported headache in the treated groups (8.0%) than the placebo groups (12.4%) (odds ratio, 0.67; 95% CI, 0.61 to 0.74; PϽ0.001). About 1 in 30 treated persons benefited by having headache prevented. The prevalence of headache was reduced (PϽ0.001) in trials of each of the 4 classes of drugs. Conclusions-Our results show that blood pressure-lowering drugs prevent a significant proportion of headaches. That this effect is seen with pharmacologically unrelated classes of drugs indicates that it is likely to be due to the reduction in blood pressure per se, the only recognized action that the drugs have in common. This in turn indicates that high blood pressure is a cause of headache, but this conclusion is not supported by observational studies of blood pressure and headache. The uncertainty over whether high blood pressure causes headache does not, however, detract from the practical benefits of the use of blood pressure-lowering drugs in preventing headaches and cardiovascular disease.

Letter Regarding Article by Law et al, “Headaches and the Treatment of Blood Pressure: Results From a Meta-Analysis of 94 Randomized Placebo-Controlled Trials With 24 000 Participants”

“…All previous studies addressing this issue had important limitations, which left this as a medical impasse. The same seems to occur in a recent publication by Law et al 1 in Circulation. After a judicious selection of 94 randomized trials with 4 classes of blood pressure-lowering drugs at fixed doses, the authors concluded that all classes reduce the prevalence of headache by one third, suggesting that high blood pressure is a cause of headache.…”

“…The number of patients treated with a symptomatic drug who reached discharge criteria (patients reporting no symptoms, systolic pressure Ͻ180 mm Hg, and diastolic pressure Ͻ110 mm Hg) was similar to that of patients treated with antihypertensive drugs. These results no longer support the idea that headache could be a cause of high blood pressure and not a consequence, as suggested by Law et al 1 People with hypertension need treatment for hypertension, and people with headache need treatment for their headaches with prophylactic drugs, which could include antihypertensive drugs with prophylactic properties, or analgesics. Most of the time, analgesics would be a better, cheaper, and probably safer option.…”

“…Although Law et al 1 show that blood pressure-lowering drugs prevent a significant proportion of headaches, the causal relation between hypertension and headache remains ambiguous. The statistically significant inverse relation between blood pressureboth systolic and diastolic-and nonmigrainous headache in the largest cross-sectional study 2 indicates that there is a third critical, idiosyncratic, perfusion-related variable between hypertension and headache.…”

Calcium channel blockers and headache

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We recently reported a meta-analysis of 94 randomized placebo-controlled trials of blood pressure-lowering drugs in which the prevalence of headache was reported [1]. On average, one-third fewer people reported headache in the treated groups than in the placebo groups [odds ratio (OR) 0.67; 95% confidence interval (CI) 0.61, 0.74; P < 0.001].

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“…We here present the results on calcium channel blockers and headache, the net effect according to dose, from our meta-analysis of randomized trials [1,2].…”