IntroductionRifampicin is an inducer of the hepatic mixed function oxygenase enzymes involved in drug metabolism.' 2 Needle biopsy specimens of the liver from patients receiving rifampicin show an increase in cytochrome P4503 and proliferation of smooth endoplasmic reticulum in the hepatocytes.4 Rifampicin induces its own metabolism' during continuous treatment as demonstrated by a shortened half life. In addition, rifampicin can accelerate the elimination of the contraceptive pill,6 leading to menstrual disturbance and unwanted pregnancy. Tolbutamide, hexobarbitone,7 and oral anticoagulants8 are other drugs whose metabolism is similarly affected. Deterioration in renal9 and allograft function'0 associated with concomitant rifampicin treatment may be cited as indirect evidence of the effect of this drug on steroid metabolism.We report on two patients with respiratory disease in whom rifampicin affected metabolism of steroids; and we describe a study of the effects of rifampicin on the pharmacokinetics of prednisolone in seven patients.

Ten years' experience of using bronchoalveolar lavage in the treatment of 10 patients with alveolar proteinosis is reported. The diagnosis was often missed. The interval between onset of symptoms and diagnosis varied from six weeks to six years (median 2 years), so that the start of treatment was often delayed. Some patients experienced severe progressive disability before they had treatment. Whole-lung lavage proved to be a safe, repeatable procedure which provided symptomatic, physiological, and radiological improvement and allowed all 10 patients treated to return to full-time employment.Pulmonary alveolar proteinosis is a disease of unknown aetiology characterised by the accumulation of protein, phospholipid, cholesterol, and free fatty acids within the alveolar spaces. The diagnosis is confirmed by typical electron-microscopic findings in sputum, lung washings, or lung biopsy specimens, without which the condition is often mistaken for interstitial lung disease, especially sarcoidosis. Alveolar proteinosis can be treated effectively by means of whole-lung lavage,' and we report 10 years' experience of the method-53 lavages in 10 patients-to emphasise the hazards of delay in diagnosis, the safety of bronchopulmonary lavage, and the benefit which results. Patients and methodsTen patients (eight men and two women) aged 23-48 years were referred either for diagnosis (five patients) or for further management (five patients).All were dyspnoeic at rest or on mild exercise and only one, with a sedentary occupation, was still able to work. All were current smokers or ex-smokers.Measurements were made of dynamic and static lung volumes, airway resistance, gas transfer factor and the transfer coefficient, the results being expressed as percentages of the means of the predicted normal range.2 Arterial blood gas tensions were

Thirty two patients with persisting pulmonary sarcoidosis fulfilling defined criteria for treatment were managed according to a standard clinical protocol. In this an attempt was made to achieve and maintain maximal radiographic and physiological improvement with individually titrated doses of corticosteroids. Lavage cell counts, serum angiotensin converting enzyme (SACE) determinations, and gallium-67 scans were planned at standard intervals but were not used in management decisions. The study analysed serial measurements in relation to changes in the clinical measurements. Twelve patients' radiographs showed complete clearing, seven cleared partially, and 13 had partial clearing with evidence of fibrosis. There was no predictive value in the initial lavage lymphocyte counts or the SACE or gallium measurements. Notably, in seven patients, substantial radiographic improvement was observed when the initial lavage lymphocyte counts were normal. Higher initial lavage neutrophil counts (p < 002), higher initial radiographic profusion scores (p < 002), and lower vital capacity (p < 001) and carbon monoxide transfer factor (p < 005) were related to incomplete clearing. A repeat study of the patients when their radiograph had cleared maximally showed that the levels of lavage lymphocytes, SACE, and gallium tended to fall, but frequently remained raised even in the presence of a normal radiograph or vital capacity or both. On the other hand, however, most of the patients with a normal lavage lymphocyte count showed persisting abnormality of the radiograph, lung function measurements, SACE, and gallium scan (or of at least one of these indices). The interrelationships between changes in clinical indices (radiograph, vital capacity, and transfer factor) and in lavage lymphocyte counts, SACE, and gallium scans showed that concordance was fairly poor in each comparison; lavage lymphocytes showed a greater major discordance than did the other pairs of measurements. Symptom free patients with normal or stable radiographic appearances have been followed for many months and have shown no clinical deterioration despite abnormal lavage lymphocyte counts, SACE, and gallium scans. Radiographic relapse; within the criteria defined, was seen in only four patients during the study; this was reflected in the gallium counts in three and in SACE and lavage lymphocyte counts measurements in two.It is concluded that serial lavage lymphocyte counts, serum angiotensin converting enzyme measurements, and gallium-67 scans are not consistently more sensitive methods by which to monitor patients with sarcoidosis during treatment than are serial measurements of high quality radiographs and results of standard lung function tests.

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1 Eight patients with airways obstruction were investigated to determine if dietary components had any significant effect upon serum concentrations of theophylline when taking a slow release formulation.2 A high carbohydrate, low protein diet, given for 1 week, resulted in the area under the concentration time curve for 12 h being 33.3% greater than a high protein low carbohydrate diet given under the same conditions. 3 In contrast to two previous studies no significant effect upon the elimination half-life was detected after changing from one diet to the other and an effect of dietary components upon absorption and/or distribution needs to be considered. 4 Morning and afternoon trough levels were significantly different from each other on both diets suggesting that theophylline kinetics are different at night. 5 Individualising of theophylline dosing is particularly needed when treating patients on a varied dietary intake.