At Dr. Hughes' Lupus Clinic at St. Thomas', Plaquenil is the favoured drug as it seems to be less indigestible and has less side effects. Although mepacrine is useful, at higher doses it causes a yellow pigmentation of the skin, so that low doses can only be given. The drug takes two to three weeks to start working effectively but in many patients there is improvement in the skin and their general well-being, less joint pain, tiredness, muscle aches and sometimes, where there is a temperature, less fever. Antimalarials can be given for months and years. Side effects of antimalarials They can affect the retina of the eye.
Hydroxychloroquine is less toxic and lower doses are safer.
However, it is vital that annual eye checks are carried out by an ophthalmologist , a medical doctor who specialises in eyes. This is different from an optician or optometrist. At St. Thomas', a five year study on patients revealed no cases of eye damage. An extremely rare problem is darkening of the skin and nails, although this is normally only seen in patients on higher doses. One rare side effect which is not widely known, even by doctors, is when hydroxychloroquine is started in moderate doses, such as two or three tablets daily, there is a subtle effect on the eye muscles leading to focussing or to mild double vision.