Introduction: Chloroquine was initially developed as an antimalarial drug. During the second world war chloroquine and related drugs were extensively used as prophylaxis especially in the Pacific area. A number of individuals with Discoid Lupus used it and incidentally noted an improvement in their skin lesions. This led to trials and in the course of these trials, an improvement in arthritis was also found. Today Chloroquine is used not only in Lupus but also in rheumatoid arthritis.

How does it work?: This is not known but it seems likely that it reduces the effectiveness of communication between cells in the immune system. These cells "communicate" via receptors on their surface. Chloroquine interferes with this process, resulting in a reduction in inflammation.

How do I take it : Chloroquine is a small white bitter tablet taken once a day. The number of tablets taken per week is calculated by height of the individual and some patients need to take only 5 or even 3 tablets a week.

Chloroquine works slowly and you should not expect to feel any improvement on this drug for up to 3-4months. To overcome this long action many doctors use a small dose of a steroid (such as prednisone) which is quick acting, to give relief. If there is a good response to chloroquine then it is possible to stop the steroid after a few months. The body can only get rid of the chloroquine slowly. So if you miss a dose there is no need to double the dose the next day. If for some reason you have to stop chloroquine suddenly there are no side effects.

Does it interact with other drugs?: This is a very uncommon - but you should nevertheless discuss all the drugs you are using, including non prescription drugs, with your doctor.

What happens if I become pregnant: This is a difficult question to answer. In some, older reports there are accounts of ear and eye damage to babies born to women on chloroquine. These patients were generally taking higher doses than are used now. Some doctors believe that in lupus erythematosus it is safer to continue the drug than to stop it. Lupus may flare in pregnancy and the danger from active disease may be greater that from the drug. However in rheumatoid arthritis which often improves in pregnancy many doctors feel that it is safer to stop the drug. Recent studies from the USA and UK could not find definite evidence that medicines like chloroquine harmed the foetus. If you plan to fall pregnant it always important to discuss it with your doctor and he will decide on the safest course of action.

What are the side effects: The most feared side effect is that of loosing vision. On the doses of chloroquine which are used today the risk of eye damage is very small. When antimalarials were first used for arthritis they were used in much higher doses than at present. Furthermore patients were not regularly checked. Despite the v slight chance of eye damage, most rheumatologists send their patients to an ophthalmologist every six months for a check. The problem is that our eyes do change with age, and often these changes are not easy to separate from those due to chloroquine. Nevertheless if changes do occur, they occur slowly and can be picked up on routine screening. Even if they may be due to age most doctors would stop the drug to ensure that no unnecessary damage occurs.

Some people do find difficulty on focusing when first starting chloroquine this does not indicate that the eyes are being damaged. It is more a sign of the eye muscles adjusting to the presence of the drug.

Other side effects are those of nausea and occasionally vomiting. This can be counteracted by taking the tablets with food. Rarely the skin can become hyperpigmented and skin may become scaly and thick. But this is rare, and will disappear when the drug is stopped

Very rarely there may be weakness, headaches or "singing in the ears" If you have any symptoms which you feel may be due to the drug it is best to consult your doctor.

Overall chloroquine is a safe drug and can be of benefit to people with various forms of arthritis and skin disease.