Failure of conventional treatment with pyrimethamine and sulfadiazine for secondary prophylaxis of cerebral toxoplasmosis in a patient with AIDS.

patient did not receive any medication known to alter the pharmacokinetics of levofloxacin. During levofloxacin treatment, renal function improved (creatinine clearance ¼102.3 mL/min) and glucose levels were unchanged. No electrocardiographic abnormalities or any adverse effect related to levofloxacin administration were found. The patient received this dose of intravenous levofloxacin for a total of 6 days, followed by oral levofloxacin at 500 mg/12 h for an additional 4 days. Clinical cure of the respiratory infection was rapidly achieved and the patient was discharged. Written informed consent was obtained from the patient to use this treatment regimen and to obtain blood samples. Very few studies have examined fluoroquinolone pharmacoki-netics in obese patients, 2,3 and, to our knowledge, this is the first pharmacokinetic evaluation of levofloxacin in a patient with severe morbid obesity. Levofloxacin was administered at an actual body weight-adjusted dose of 4 mg/kg/12 h based on a ciprofloxacin dosage recommendation for obese patients. 2 With this regimen, the values of C max and CL were similar to those obtained in non-obese healthy volunteers receiving a dose of 750 mg/24 h, 5 the dose recommended for the treatment of community-acquired pneumonia in adults, 4 but the AUC 0 – 24 was double (143.27 mg h/L, twice the value of the AUC 0 – t because levofloxacin was administered twice daily). It has also been previously recommended that the dose of quinolones should be based on a weight correction factor of 45% of excess body weight. 3 This dose was administered to a morbidly obese patient who reached a therapeutic peak plasma concentration , but no other pharmacokinetic parameters were reported. 6 It has been suggested that this lower adjusted dosing could result in low interstitial levofloxacin levels due to impaired levofloxacin penetration in the tissues of obese patients. 2 In our patient, levofloxacin had larger absolute V ss and t 1/2 compared with those described in non-obese patients, which may be explained by a significant distribution of levoflox-acin into excess weight. 1 Regarding pharmacodynamic parameters, an AUC 0 – 24 /MIC ratio of 143.27 was achieved, a value that exceeds the optimal ratio for favourable outcomes in patients with S. pneumoniae infections. 7 In conclusion, an intravenous levofloxacin dose of 750 mg/ 12 h (4 mg/kg/12 h) in our patient with morbid obesity achieved double the adult exposure following a standard dose of 750 mg per day to non-obese healthy volunteers. Consequently, …