Effects of cicletanine on prostaglandin I2 and E2 levels in patients with essential hypertension

Cicletanine-induced hyponatremia and hypokalemia in kidney transplant patients

Background

Cicletanine is an antihypertensive agent with vasorelaxant and diuretic properties. It has been widely used in European countries; however, cicletanine-associated electrolyte disturbances have yet to be defined. We investigated cicletanine-induced hyponatremia and hypokalemia in kidney transplant patients.

Methods

Data from a total of 68 kidney transplant recipients who were treated for hypertension with cicletanine were retrospectively analyzed. Cicletanine-induced hyponatremia and hypokalemia were defined as serum sodium < 135 mmol/L and potassium < 3.5 mmol/L, respectively, after the use of cicletanine.

Results

The average patient age was 50 (±11) years, and 44 (65%) were male. The daily dose of cicletanine was 171 ± 46 mg, and the duration of drug use was 215 ± 514 days. Hyponatremia occurred in 11 patients (16.2%), and hypokalemia occurred in 8 patients (11.8%). Three patients (4.4%) had hyponatremia and hypokalemia simultaneously. The duration of cicletanine administration was significantly longer in patients with hyponatremia than in those without hyponatremia (943 ± 958 vs. 74 ± 166 days, P < 0.05). The occurrence of hypokalemia was not affected by either daily dose or duration of drug use. Among 11 patients with hyponatremia, 10 were corrected within 2 weeks after withdrawal of the drug and 1 was spontaneously corrected. Among 8 cases of hypokalemia, 7 were corrected after withdrawal of the drug and 1 was spontaneously corrected.

Conclusion

We demonstrate that cicletanine may induce hyponatremia or hypokalemia in kidney transplant patients. Hyponatremia is more frequently associated with cicletanine than hypokalemia, and extended use of cicletanine may increase the risk of hyponatremia.

Different patterns of renal prostaglandins I2 and E2 in patients with essential hypertension with low to normal or high renin activity

OBJECTIVE

Differences in renal synthesis between prostaglandins I2 and E2, and the relationships of the amounts synthesized to renin release were investigated in patients with essential hypertension.

METHODS

Of 12 inpatients, six had low to normal plasma renin activity and six had high renin activity. Before and 30 min after intravenous injection of aspirin D,L-lysine (18 mg/kg), abdominal aortic and renal venous plasma was sampled and assayed for renin activity, 6-ketoprostaglandin F1alpha (as an index of prostaglandin I2), and prostaglandin E2.

RESULTS

In patients with low to normal renin activity, mean +/- SD plasma levels of 6-keto-prostaglandin F1alpha were lower in the right and left renal veins (3.6 +/- 1.4 and 4.1 +/- 1.5 pg/ml, respectively) than in the aorta (5.5 +/- 2.0 pg/ml), but in the other patients, the levels in these veins (7.0 +/- 2.4 and 6.5 +/- 1.5 pg/ml) were higher than in the aorta (5.4 +/- 0.9 pg/ml). Plasma prostaglandin E2 levels in both veins were higher than in the aorta in both groups and, at each site, the levels were similar in the two groups. Aspirin suppressed renin release in the patients with high renin activity.

CONCLUSIONS

In patients with essential hypertension with low to normal renin activity, either less prostaglandin I2 than prostaglandin E2 is produced in the kidney or else more is metabolized there, and in such patients with high renin activity, the renal synthesis of prostaglandin I2, more than that of prostaglandin E2, seems to be related to the increased renin release.