- diabetes
- myasthenia gravis (a type of muscle weakness)
- deficiency in glucose-6-phosphate dehydrogenase (G6PD)
- HIV or other immuno-suppressive disease
- epilepsy, fits or any other neurological conditions
- history of tendon problems during previous treatment with antibiotics
- Liver problems
- Kidney problems
- heart disease or heart problems
- any serious medical condition which may require immediate hospitalisation