Brand names None
Used in the following combined preparation Maloprim
GENERAL INFORMATION
Dapsone is an effective treatment for Hansen’s disease, also known as leprosy.
The drug is prescribed for all forms of the disease, in combination with other drugs such as rifampicin. For tuberculoid leprosy, treatment should be continued for at least two years. For lepromatous leprosy, lifelong treatment may be
necessary. Another use of dapsone is in combination with pyrimethamine (as Maloprim) for the prevention of malaria.
Dapsone may also be used to treat dermatitis herpetiformis. This skin condition often occurs together with coeliac disease, in which the bowel is abnormally sensitive to gluten (a wheat protein). In combination with a gluten-free diet, dapsone treatment improves the skin condition.
Side effects are rare with dapsone, even during prolonged treatment. The most serious adverse effect is haemolytic anaemia. Periodic blood tests are recommended to detect the early signs of this disorder.
QUICK REFERENCE
Drug group Antibacterial drug
Overdose danger rating Medium
Dependence rating Low
Prescription needed Yes
Available as generic Yes
INFORMATION FOR USERS
Your drug prescription is tailored for you. Do not alter dosage without checking with your doctor.
How taken
Tablets.
Frequency and timing of doses
Once daily (leprosy); 3-4 x daily (dermatitis herpetiformis).
Dosage range
Adults 50-100mg daily (leprosy); 50mg initially increased up to 400mg daily. The dose is reduced to a minimum as soon as possible. Sometimes this is as low as 50mg weekly (dermatitis herpetiformis). Children Reduced dose according to age and weight.
Onset of effect
Within a few weeks (leprosy); 1-3 days (dermatitis herpetiformis).
Duration of action
30-150 hours.
Diet advice
A gluten-free diet may be recommended for dermatitis herpetiformis sufferers.
Storage
Keep in a closed container in a cool, dry place out of the reach of children.
Protect from light.
Missed dose
Take as soon as you remember. If your doses are scheduled 3-4 times daily, and your next dose is due within 2 hours, take a single dose now and skip the next.
If your doses are scheduled once daily, and your next dose is due within 8 hours, take a single dose now and skip the next.
Stopping the drug
Do not stop the drug without consulting your doctor; symptoms may recur.
Exceeding the dose
An occasional unintentional extra dose is unlikely to cause problems. Large overdoses may cause nausea, vomiting, dizziness, and headache. Notify your doctor.
SPECIAL PRECAUTIONS
Be sure to tell your doctor if:
You have long-term liver or kidney problems.
You have glucose-6-phosphate dehydrogenase (G6PD) deficiency or another blood disorder
You are allergic to sulphonamides.
You are taking other medications.
Pregnancy
Safety in pregnancy not established. If dapsone is taken, folate supplements should also be taken by the mother. Discuss with your doctor.
Breast-feeding
The drug passes into the breast milk, but at normal doses adverse effects on the baby are unlikely. Discuss with your doctor.
Infants and children
Reduced dose necessary.
Over 60
Reduced dose may be necessary.
POSSIBLE ADVERSE EFFECTS
Side effects are rare at normal doses. Loss of appetite, tiredness, or weakness may be signs of haemolytic anaemia and should be reported promptly to your doctor.
INTERACTIONS
Rifampicin may lower the blood levels of dapsone, requiring an increase in dosage.
Probenecid increases the levels of dapsone, and the risk of side effects.
Driving and hazardous work
Problems are unlikely.
Alcohol
No known problems.
PROLONGED USE
There is a risk of serious blood disorders with prolonged use of dapsone.
Monitoring Periodic blood counts and liver function tests may be performed.
