In the treatment of tuberculosis with rifampicin in patients treated with prednisolone and cyclosporine, we have to increase the dosage of these drugs. Although prednisolone dosage is recommended to be doubled, there is no established consensus about cyclosporine dosage. Our aim is to review the current situation at our institution regarding the dosage of cyclosporine administered to tuberculous patients after the addition of rifampicin to the treatment regimen.We reviewed patients' clinical status and how dosages of cyclosporine were altered during a course of tuberculosis treatment including rifampicin in 4 patients (2 interstitial pneumonitis, 2 collagen vascular disease) who were being treated with cyclosporine between 2001 and 2003. Prednisolone had been also administrated in all patients and the dosage was doubled from the beginning of the treatment. The appropriate dosage of cyclosporine was found to be 2.5-3.5 (average 3) times that of initial dosage, and it required 5-12 weeks (average 8.3) measurements of trough levels and 6-27 (average 12) weeks until appropriate trough levels were obtained.The appropriate dosage of cyclosporine was found to be approximately 3 times that of the initial dosage in all patients, but it required a long-term and frequent measurements of trough levels before reaching this goal. It seems that trebling the dosage of cyclosporine from the start of anti-tuberculosis chemotherapy will be an efficient way to achieve good clinical outcome.

Cystic fibrosis (CF) patients require higher dosages of many antibiotics. The relapse of tuberculosis in one CF patient, and the repeated growth of Mycobacterium avium-intracellulare in another, despite conventional therapy, raised the question of whether the serum levels of the antimycobacterial drugs were adequate. Antimycobacterial drug serum concentrations were assayed in 10 CF patients with pulmonary mycobacterial disease. Serum levels below the proposed target range were seen 2 h after drug intake in the initial four patients treated: for rifampicin in 2/3, ethambutol in 3/4 and for clarithromycin in 2/3 patients, despite standard dosages. Reassays after dose adjustment and assays in six other patients showed that adequate levels were not achieved 4 h after clarithromycin in 3/5, ethambutol in 1/5, ciproflaxacin in 1/2 and ofloxacin in 2/2 patients. The patient with relapse of tuberculosis and the patient with continuous growth of M. avium-intracellulare improved and became culture negative after dose adjustment. Low drug serum levels is one reason for therapy failure in cystic fibrosis patients with mycobacterial disease. Therapeutic drug monitoring is recommended.