You should not use DoxyPEP if:

You have an allergy to any antibiotics from the tetracycline family (a class of antibiotics that treat several kinds of bacterial infections)

You are taking certain medications as taking doxycycline at the same time may increase the risk of negative side effects, or affect the levels of doxycycline or the other drugs in your body. These medications include:

• Other antibiotics including rifampicin
• Acne medication containing vitamin A
• Warfarin medicine to prevent blood clots
• Carbamazepine and phenytoin medications for epilepsy
• Ciclosporin, a medicine to regulate the immune system

If you are taking prescribed drugs or medicines, if you are pregnant or think you might be, it is advised that you speak to your doctor or healthcare provider before taking doxyPEP.