Rifampicin

Rifampicin is an antibiotic used to treat serious bacterial infections. It may be prescribed by dermatologists for the treatment of:

• Recurrent boils
• Folliculitis decalvans
• Hidradenitis suppurativa
• Tuberculosis
• Leprosy

It is also used to treat Brucellosis, serious staphylococcal infections and to clear asymptomatic carriers of Neisseria meningiditis (which can cause meningococcal disease).

Rifampicin is active against a variety of organisms including Staphylococcus aureus, Staphylococcus epidermidis, Mycobacterium tuberculosis, Mycobacterium leprae, Neisseria meningiditis and Brucella species.

It should always be prescribed with another antibiotic, in order to prevent bacterial resistance, which can develop rapidly if it is used alone.

It should be taken on an empty stomach at least 30 minutes before a meal or 2 hours after a meal. Antacids should be given at least 1 hour after rifampicin.

In New Zealand rifampicin is available as:

• Rifadin™ tablets, suspension and intravenous infusion
• Rifinah™ tablets, where it is combined with isoniazid for the treatment of tuberculosis and leprosy

Side Effects

Rifampicin is usually well tolerated and rarely causes serious toxicity. The commonest side effects involve skin and the gastrointestinal system.

Bodily fluids

Tears, sweat and urine may become orange coloured and contact lenses may be permanently stained.

Skin

Usually mild and self-limiting flushing and itching with or without rash. Hives are uncommon. Erythema multiforme and toxic epidermal necrolysis have rarely been reported.

Gastrointestinal

Loss of appetite, vomiting, abdominal pain and diarrhoea.

Liver

Hepatitis, particularly if rifampicin is given with isoniazid

Blood

Thrombocytopaenia (low platelets potentially resulting in bruising and bleeding), rarely low white blood cell count and disseminated intravascular coagulation, and very rarely agranulocytosis (severely decreased white blood cell counts).

Musculoskeletal

Muscle weakness and myopathy are uncommon

Rifampicin is sometimes used intermittently (less than 2 to 3 doses per week) for the treatment of tuberculosis and leprosy. When rifampicin is used in this way, it may be associated with a ‘flu-like syndrome, shortness of breath, low blood pressure, acute renal failure and shock.

Drug interactions

Rifampicin may increase the breakdown of other medications, making them less effective. The dosage of these drugs may need adjustment if taken together with rifampicin:

• Anticoagulants (warfarin)
• Anticonvulsants (phenytoin)
• Antiarrhythmics (disopyramide, mexilitine)
• Antipsychotics (eg haloperidol)
• Antifungals (eg itraconazole)
• Antiretroviral drugs (eg zidovudine)
• Beta blockers
• Calcium channel blockers (eg diltiazem, verapamil)
• Chloramphenicol
• Clarithromycin
• Corticosteroids
• Ciclosporin
• Dapsone
• Digoxin
• Oral contraceptives
• Benzodiazepines (eg diazepam)

Precautions

• Non-hormonal contraceptive methods may be necessary in women of child bearing age when taking rifampicin, due to its effects on oral contraceptives.
• If used in pregnancy, it may be harmful to the fetus without causing malformations. Appears in breast milk.
• Baseline blood tests should be done in adults, including a blood count, renal and liver function tests. If there are significant abnormalities, these should be repeated during treatment. Caution should be taken when there is pre-existing liver disease or liver function abnormalities.