Severe infectious diseases result in an increased volume of distribution. Renal function is usually impaired, but can in fact be increased early in the course of the disease. In renally cleared drugs with a small therapeutic index a dose reduction should take place or these medications should be temporarily discontinued. Renally cleared antibiotics may be subject to subtherapeutic levels of antibiotics, especially early in the course of the disease. Diuretics and RAAS inhibitors should usually be interrupted during acute illness; bèta-blockers should be continued. Statins can usually be continued. Paracetamol can usually be prescribed. NSAIDs, however, are almost always contra-indicated. Patients with chronic use of corticosteroids should receive a stress dose. There is no evidence to support discontinuing immunosuppressants. Platelet aggregation inhibitors and directly acting oral anticoagulants are continued, whereas coumarins should be monitored vigorously or substituted for low molecular weight heparins.