What Factors Affect a Sufficient Rifampicin Dose?

The establishment of a sufficient rifampicin dose depends on a number of factors, including the condition for which it is being used, the weight of the patient, and his or her renal and hepatic function. Rifampicin is an antibiotic drug used in combination with others to treat tuberculosis (TB), for a number of other bacterial infections, and for the prevention of meningitis in people at risk. It is available in most countries by prescription only and may be known by different trade names, according to manufacturer.

Rifampicin works by inhibiting RNA-polymerase, an enzyme involved in bacterial synthesis. By blocking the action of the enzyme, rifampicin prevents replication of the bacteria. When rifampicin is used to treat bacterial infections, including tuberculosis, it is used in combination with other antibiotics, to prevent the development of resistance. When treating tuberculosis, the doctor may take a sample from the patient, such as sputum, to establish bacterial susceptibility and to allow the correct choice of drugs for treatment.

The rifampicin dose for treatment of tuberculosis is usually established on a per kilogram basis in both children and adults. In severe liver or kidney failure the rifampicin dose may be reduced slightly. In cases of severe tuberculosis, or that affecting organs other than the lungs, a higher rifampicin dose may be given and the treatment course may be over a longer period. Treatment of tuberculosis is usually over many months with a number of different drugs, including rifampicin.

For the treatment of asymptomatic meningitis carriers, the rifampicin dose in adults is usually 600 mg twice a day for two days. The dose for children is, again, established by weight. Rifampicin is not used to treat meningitis, but to prevent it.

Resistance to rifampicin may occur and it is for this reason that the full prescribed course of rifampicin, and the other medications prescribed, must be completed, even if symptoms have resolved. It is also for this reason that repeated cultures may be done on samples from the patient. Should resistance occur, a change in treatment may be necessary.

As with any medication, rifampicin may interact with other medications and cause adverse effects. Any other medication, including complementary, over-the-counter and homeopathic preparations should be disclosed to the treating doctor. Adverse reactions which have been reported include liver toxicity, gastrointestinal side effects and discoloration of body fluids such as tears and urine. Should any untoward effects occur, medical attention should be sought.