What are the aims of this leaflet?
This leaflet has been written to help you understand more about mepacrine. It tells you what it is, how it works, how it is used to treat skin conditions, and where you can find out more about it.
What is mepacrine and how does it work?
Mepacrine (an unlicensed drug in the UK of which there are many) was introduced as a treatment for malaria and for certain other tropical infections. It is one of several antimalarial drugs that have been found to also have anti-inflammatory properties, which can help some skin conditions.
What does “unlicensed” mean in relation to a drug?
An unlicensed drug is one that has not been awarded a Market Authorisation from the UK Medicines Healthcare Products Regulatory Agency (MHRA). A drug may be licensed in other countries, but not in the UK. Drug licenses in the UK are awarded following a rigorous process of evaluation by the MHRA after an application by a pharmaceutical company. Once awarded, the licensed drug can then be marketed and sold in the UK.
In the absence of a license, the drug may still be prescribed in the UK, provided there is funding available locally to pay for it. Additionally, there must be clear evidence to confirm that the drug is effective for the condition in question and that safety concerns have been adequately addressed. Even after such evidence has been supplied it is still a matter for the local formulary group (a multidisciplinary group who make decisions on the prescribing of medicinal drugs at a local level) to make a final decision on a case-by-case basis.
Mepacrine is widely used for lupus in many countries, including the UK and North America, but at the moment remains unlicensed and can only be obtained from a ‘Specials’ pharmaceutical manufacturer.
Which skin conditions are treated with mepacrine?
Mepacrine is used particularly to treat discoid lupus erythematosus and for subacute cutaneous lupus erythematosus. Mepacrine has also been used in the treatment of erythema multiforme, sarcoidosis and dermatomyositis (please see the relevant BAD Patient Information Leaflets).
What dose of mepacrine should I take?
Your doctor will advise you about this. For skin conditions, the dose may be as small as 50 mg (half a 100 mg tablet) taken three times a week. A maximum dose would be 100 mg, taken three times a day. The dose for children is 2 mg per kg bodyweight, given as a split dosage three times a day (to a maximum of 300 mg daily). It may take several weeks to reach its full effect so you may not experience any benefit immediately but it is important to keep on taking your mepacrine.
What are the possible side effects of mepacrine?
Mepacrine is tolerated well at the low doses used in dermatology. However, it can have some undesirable side effects:
- Yellow discoloration of the skin and urine may occur during long-term treatment or with large doses. This is common, but quite harmless, and should not be a cause for concern as it goes away when you stop the drug. Similarly, the roof of the mouth, nails and eyes may be discoloured blue or black, which also resolve when you stop taking the drug.
- Mepacrine can cause dizziness, particularly when you get up from sitting or lying down. Getting up slowly should help to reduce this side effect.
- Other possible side effects include stomach upsets, headaches, feeling sick and being sick, skin rashes (occasionally severe), and changes in mood or behaviour. Fits may occur with overdosing. Liver inflammation and alterations in the blood count can occur but are rare.
Mepacrine should be used with caution in:
- patients with porphyria
- elderly patients
- the presence of liver disease
Mepacrine is best avoided by patients who have psoriasis as it can make this condition worse. It should also be avoided in myasthenia gravis (a muscle weakness autoimmune condition) and by patients with a history of the psychoses (severe forms of mental illness).
How will I be monitored for the side effects of mepacrine treatment?
Blood tests are usually performed twice a year to check your blood count and liver function.
Can I have vaccinations while I am on mepacrine?
Yes, this should not be a problem. If you are travelling to a place where malaria occurs, mepacrine alone will not provide adequate protection against malaria and you must see your GP to be prescribed additional antimalarial treatment which may be taken at the same time as mepacrine.
Does mepacrine affect fertility or pregnancy?
There are no data on the use of this drug in pregnancy and breastfeeding.
Consequently, it is recommended that you should avoid taking it if you are pregnant or planning a pregnancy, or if you are breast feeding.
May I drink alcohol while I am taking mepacrine?
Mepacrine has been reported to produce a mild flushing reaction when taken with alcohol. There may be symptoms such as a racing heartbeat, dizziness, headache, shortness of breath, and sickness. If you experience these symptoms it is advisable to avoid alcohol.
Can I take other medicines at the same time as mepacrine?
Mepacrine is often used in conjunction with hydroxychloroquine for additional benefits. This is safe, however, some drugs do interact with mepacrine. For example, mepacrine may increase the blood level of primaquine (a medication used in the treatment of malaria), resulting in a higher risk of toxicity, and it has been recommended that these two drugs should not be used together.
You should always let any doctors who are treating you know that you are taking mepacrine.
Where can I find out more about mepacrine?
If you want to know more about mepacrine, or if you are worried about your treatment, you should speak to your doctor or pharmacist. This information sheet does not list all of the side effects of mepacrine. For more details, please look at the information sheet which comes as an insert in your prescribed mepacrine box.
Web links to detailed leaflets:
For travel advice:
For details of source materials used please contact the Clinical Standards Unit (firstname.lastname@example.org).
This leaflet aims to provide accurate information about the subject and is a consensus of the views held by representatives of the British Association of Dermatologists: individual patient circumstances may differ, which might alter both the advice and course of therapy given to you by your doctor.
This leaflet has been assessed for readability by the British Association of Dermatologists’ Patient Information Lay Review Panel
BRITISH ASSOCIATION OF DERMATOLOGISTS
PATIENT INFORMATION LEAFLET
PRODUCED JULY 2006
UPDATED MARCH 2010, APRIL 2013, AUGUST 2016
REVIEW DATE AUGUST 2019