[Effect of diltiazem on lipid profiles and heart rate in hypertensive patients]

Diltiazem is an antihypertensive belonging to the class of heart rate-slowing calcium channel blockers; its antihypertensive efficacy has been demonstrated for a long time. Controlled trials have also demonstrated that it does not interfere with lipid parameters. This open multicentre trial was designed to verify the absence of any action of diltiazem on lipid parameters as well as its effect on the heart rate of hypertensive patients. The patients included had to take one capsule of diltiazem 300 mg sustained release formulation, developed by Laboratoires Synthélabo, in the morning for 6 months. A lipid assessment and an electrocardiogram were performed before and at the end of the trial. One hundred and forty-six patients were included: 81 underwent a complete lipid assessment (7 parameters) before and after treatment and 69 underwent an electrocardiogram at rest to the same study times. Total cholesterol (p = 0.0007), LDL cholesterol (p = 0.005) and apoprotein A1 (p = 0.0002) were significantly decreased. Blood pressure decreased progressively throughout the study and was "controlled" (supine diastolic blood pressure < or = 90 mmHg) after six months of treatment in 77% of patients. Heart rate decreased significantly at the end of the study; no pathological variation of PR, QRS and Qt intervals was observed. The effect on heart rate, also studied in patient subgroups defined by their baseline values, was more marked when the baseline heart rate was increased. The investigators considered the safety to be good at each visit, in 80% of cases. Sixteen patients dropped out of the trial because of adverse effects or intercurrent disease. The adverse effects most frequently reported were oedema of the lower limbs (7.5%), headache (4.8%) and hot flushes (2.7%). No harmful effect of diltiazem on lipid parameters was observed during this open trial; some lipid parameters even decreased at the end of treatment. Clinically, diltiazem lowered blood pressure and decreased heart rate. The reduction of heart rate was more marked in the case of high baseline heart rate. Safety was satisfactory.