Trimethoprim‐Sulfamethoxazole as Toxoplasmosis Prophylaxis for Heart Transplant Recipients

Sir—Toxoplasmosis is a disease that is highly transmissible to D ϩ /R Ϫ patients (i.e., patients who are seronegative for Toxoplasma gondii IgG antibodies and who receive a heart transplant from donors who are seropositive for T. gondii IgG antibodies). This disease, along with disseminated aspergillosis, is associated with the highest mortality rate attributable to an infectious complication in heart transplant recipients. For these high-risk patients , 25 mg of pyrimethamine is given as toxoplasmosis prophylaxis for 6 weeks after surgery [1–3]. We read with interest the article on heart transplantation by Montoya et al. [1]. In their extensive review of the experience with heart transplantation patients at Stanford Medical Center (Stan-ford, CA), there was not enough data to assess whether administration of trimeth-oprim-sulfamethoxazole (TMP-SMZ) for prophylaxis against Pneumocystis jiroveci (formerly known as " Pneumocystis cari-nii ") is sufficient to prevent toxoplasmosis in D ϩ /R Ϫ patients. The authors concluded that, until more data are available, it seems prudent to recommend a 6-week course of pyrimethamine for these patients [1]. The problem is that pyrimethamine does not provide effective prophylaxis against P. jiroveci, so both drugs should be used simultaneously [4]. In 1994, reported experience with HIV-infected patients showed that TMP-SMZ might be useful as toxoplasmosis prophy-laxis for heart transplant recipients [5]. On the basis of this experience, we decided to begin a trial of TMP-SMZ (a single double strength tablet given 3 times each week) as prophylaxis against toxoplas-mosis and P. jiroveci. Before the start date of the trial, we had followed standard recommendations and had used pyrime-thamine for toxoplasmosis prophylaxis and TMP-SMZ for Pneumocystis pneumonia prophylaxis. Since 1988, a total of 315 patients have undergone heart transplantation at Hospital General Universitario Gregorio Ma-rañó n (Madrid, Spain); of these patients, 32 (10.2%) were considered to be D ϩ /R Ϫ patients with regard to Toxoplasma IgG antibody serostatus. Twelve of the patients received pyrimethamine, 17 received TMP-SMZ, and 3 did not receive any prophylaxis. Two cases of toxoplasmosis occurred among all our heart transplant recipients; one case occurred in 1990 and was associated with pulmonary involvement, and the other case occurred in 1991 and was associated with meningitis, chorioretinitis, and myocardial involvement (the latter of which was proven by biopsy). None of the patients had been receiving any kind of prophylaxis. The first case of toxoplas-mosis developed only 5 days after trans-plantation and before prophylaxis was started. Prophylaxis …