[Pleurodesis with tetracycline in neoplastic effusions. Is an acid pH necessary?].

Forty-three patients with recurrent malignant pleural effusions were included in a prospective protocol of treatment with two different types of tetracycline. Twenty-one patients (series A) were treated with a saline dilution of oxytetracycline (pH = 8) and twenty-two (series B) with a saline dilution of tetracycline chlorhydrate (pH = 2). Among the patients of series A, the rate of no recurrence of the effusion was 85.7% (12 out of 14 correctly treated and followed-up patients). In the series B, the rate of no recurrence was 86.6% (13 out of 15). The authors conclude that the pH of the tetracycline is not a determinant of pleural symphysis. The mechanism of action of the intrapleural tetracycline is discussed.