Forman JP et al. (2005) Non-narcotic analgesic dose and risk of incident hypertension in US women. Hypertension 46: 500–507

Women who take high daily doses of acetaminophen and some nonsteroidal anti-inflammatory drugs (NSAIDs) have an elevated risk of developing incident hypertension, a prospective study carried out in the US has shown.

Forman and colleagues investigated a possible association between the dose of analgesic drugs used and incidence of hypertension among 1,903 women aged 51–77 years who participated in the Nurses' Health Study I and 3,200 women aged 34–53 years from the Nurses' Health Study II. Women included in the study had no history of hypertension at baseline. They completed detailed questionnaires about their use of acetaminophen, aspirin or other NSAIDs, including average daily doses and indications for their use. Information was also gathered about relevant confounders such as alcohol intake and history of smoking. Study participants were then followed up prospectively to find out whether they developed hypertension.

Women in both age-groups who took at least 500 mg of acetaminophen daily were almost twice as likely to develop hypertension as those who did not use acetaminophen. Among women aged 51–77 years who used at least 400 mg NSAIDs daily, the risk of hypertension increased by almost 80%, whereas for younger women (aged 34–53 years) the risk of hypertension was 60% higher compared with individuals who did not use NSAIDs. Interestingly, high doses of aspirin were not associated with an increased risk of developing hypertension in either age-group.

According to the researchers, these results have significant public health implications and suggest that acetaminophen and NSAIDs should be used with greater caution.