Doxazosin, but not amlodipine decreases insulin resistance in patients with chronic renal failure: a prospective, randomized-controlled study.

Insulin resistance (IR) in chronic renal failure (CRF) is well-known. In this randomized-controlled study, we aimed to compare the effect of doxazosin and amlodipine on IR in patients with CRF. Fifteen patients with CRF (male/female: 5/10, mean age: 46 +/- 13 years) and 9 controls (male/female: 3/6, mean age: 35 +/- 8 years) were included. Patients and controls had no family history of diabetes mellitus. Homeostasis model assessment (HOMA) was calculated as a marker of IR. Patients were grouped randomly to doxazosin (n = 8; 2-4 mg/day) and amlodipine (n = 7; 5-10 mg/day) arms. Baseline biochemical analysis (fasting serum glucose, BUN, creatinine, uric acid, cholesterol and cholesterol subgroups) and parameters related with insulin metabolism (insulin, C peptide, HOMA) were similar between amlodipine and doxazosin groups. There was no difference in age, gender and body mass index among study groups. The follow-up time was 12 weeks. Patients with CRF had higher HOMA (1.83 +/- 0.55 vs 1.00 +/- 0.36, p = 0.001), fasting insulin (8.06 +/- 1.98 vs 4.46 +/- 1.31 IU/l, p < 0.001) and serum triglyceride levels (197 +/- 136 vs 112 +/- 67 mg/dl, p = 0.04) as compared to controls. Serum HDL cholesterol levels were significantly lower in patients with CRF than controls (40 +/- 10 vs 57 +/- 14 mg/dl, p = 0.02). HOMA significantly decreased after doxazosin (1.91 +/- 0.45 vs 1.41 +/- 0.21, p = 0.02), however, no difference was found after amlodipine. Also, fasting insulin levels were decreased after a 12-week doxazosin therapy from 8.17 +/- 1.22 vs 6.58 +/- 0.84 IU/l, p = 0.02), but no change was seen after amlodipine. Lipid parameters did not significantly change during the study period in 2 groups. No adverse effect requiring drug discontinuation was observed during the 12-week period in the study groups. In conclusion, doxazosin decreases IR in patients with CRF, whereas amlodipine has no effect. This may be of advantage in the treatment of hypertension in this group of patients for preventing some long-term complication of IR.

Immunization of renal transplant recipients with pneumococcal polysaccharide vaccine.

BACKGROUND: Streptococcus pneumoniae, a common pathogen leading to pneumonia, is a cause of morbidity and mortality in immunosuppressed patients. Vaccination against this agent can be recommended for immunosuppressed patients, including those with chronic renal failure, nephrotic syndrome and renal transplant recipients; however, a diminished immune response and loss of protective antibodies have been observed. PATIENTS AND METHODS: In our prospective study, the efficacy and side effects of polyvalent pneumococcal vaccination were investigated in renal transplant recipients. A total of 21 patients (6 female, 15 male) with well-functioning renal allografts, who had transplant surgery at least 2 months before, were included in the study. The patients were stratified according to the immunosuppressive protocol and 8 received double, while 13 received triple, immunosuppressive agents. After obtaining basal serum samples, all cases were vaccinated with the 0.5 mL intramuscular administration of polyvalent polysaccharide pneumococcal vaccine (Pneumo 23 Pasteur Merieux, lot No: K 1131). RESULTS: Following a mean of 6 wk in all patients and also a mean of 12 wk in 12 patients, serum samples were again obtained to measure pneumococcal antibodies. Antibody titers following 6 and 12 wk of vaccination were significantly higher, as compared with basal values in all patients, except one. These titers did not show any statistically significant difference between double and triple therapies. There was no significant difference between the 12th and 6th wk postvaccination antibody titers. No systemic or local adverse effects were observed. CONCLUSION: Pneumococcal vaccination is safe and effective in patients with well-functioning renal allografts, at least in the short term. This vaccination policy may be useful for preventing invasive pneumococcal disease in immunosuppressed patients.