Blood pressure reduction in hypertensive patients after withdrawal of effervescent medication.

BACKGROUND: Raised blood pressure associated with the sodium excipient content of soluble or effervescent analgesic has been previously reported. However, the influence of other anions associated with sodium on blood pressure is still controversial.
METHODS: Observational study of elderly hypertensive patients with uncontrolled blood pressure treated with effervescent paracetamol (3 g/day) for osteoarthritis. Blood pressure was measured before and after (4 weeks or more) switching paracetamol from an effervescent format to a tablet form in 34 patients. Blood pressure was recorded by community pharmacists during a pharmacotherapeutic follow-up service.
RESULTS: Sodium intake in an effervescent form was 74 mmol/day (mainly associated with sodium bicarbonate and carbonate excipients). Initial blood pressure was high (range: 153-168 mmHg systolic and 92-99 mmHg diastolic). Switching to paracetamol tablets (no sodium content) was associated with both lowered systolic pressure of 13.1 mmHg (95%CI: 11.9-14.3, p < 0.0001) and a moderate reduction of diastolic pressure of 2.5 mmHg (95%CI: 2.1-2.9, p < 0.0001). No changes in medication in the study period took place, and weight and lifestyles remained stable. A detailed review of pharmacotherapy and lifestyle reveals no other causes for blood pressure to lower.
CONCLUSIONS: A relationship of causality between the intake of high sodium excipients and high blood pressure in elderly hypertensive individuals, without chloride ions, was found. Clinicians should be aware of possible raised blood pressure when effervescent formulations are prescribed to hypertensive patients.