Heart disease or heart problems such as narrowing of the arteries (ischaemic heart disease)
Chest pains (angina), or have previously had a heart attack
Stroke or a mini-stroke (also called a transient ischaemic attack or TIA)
High blood pressure
Coronary Vasospasm (including Prinzmetal’s angina)
Wolff-Parkinson-White Syndrome (a type of abnormal heartbeat)
Peripheral Vascular Disease
Previous Gastrointestinal or Splenic infarction
Ischaemic Colitis
Epilepsy or history of seizures
Liver problems
Kidney problems
Allergy or sensitivity to antibiotics called sulphonamides (e.g. trimethoprim)
Any serious medical condition which may require immediate hospitalisation