CKS is no longer commissioned by the National Institute for Health and Clinical Excellence (NICE). NICE remains committed to providing a replacement service for CKS and is currently reviewing its options. In the meantime, although CKS content is now not being maintained, it still remains relevant and will continue to be made available. CKS content was generated under a programme of topic creation and update. To check if the topic you are viewing is current or out of date, please refer to the topic publication details by clicking on the 'How up-to-date is this topic?' link in the left hand menu on individual topic pages.
Otitis externa - Management
Who should avoid using erythromycin or clarithromycin?
- People who have had intolerable gastrointestinal effects from erythromycin:
- Consider prescribing prescribing clarithromycin.
- People taking drugs metabolized by cytochrome P450 isoenzymes (e.g. theophylline, carbamazepine, digoxin, warfarin) [Aronson, 2006]:
- The effects of these drugs may be increased because erythromycin and clarithromycin inhibit cytochrome P450 isoenzymes.
- An additional concern is that broad spectrum antibiotics can reduce the number of bacteria in the gut that produce vitamin K, and thus potentiate the effects of warfarin.
- People taking drugs that can prolong the QT interval (e.g. antiarrhythmics, antipsychotics, tricyclic antidepressants), and people with hypokalaemia:
- Macrolides also prolong the QT interval, and therefore should, if possible, not be used together with these drugs.
- Macrolides should not be used in people with hypokalaemia, which also increases the risk of QT prolongation.
- People taking statins:
- The risk of myopathy and rhabdomyolysis is increased, as macrolides can inhibit the metabolism of statins [Aronson, 2006].
- For more information on drug interactions with macrolides, see the British National Formulary [BNF 53, 2007].
© NHS Institute for Innovation and Improvement