05 June 2014

Incorrect medication worsens drug-resistant TB

Experts are concerned that we’re running into an era where we don’t have drugs available because organisms have developed resistance to these drugs.


An international expert on tuberculosis has warned about the danger of doctors prescribing incorrect or too little medication for TB. This dramatically hikes the chances of contracting or worsening drug-resistant TB, making it far harder and more expensive to treat.

It’s also causing a potential crisis around the availability of drugs that work.

“Many experts are very concerned that we’re running into an era where we don’t have drugs available because the organisms, such as TB, have developed resistance to them,” says Professor Simon Schaaf, paediatric TB researcher at the Desmond Tutu TB Centre at Stellenbosch University.

Waiting for new drugs

Schaaf says it’s vital to use TB drugs with great care so that they don’t lose their efficacy. 

Patients also need to be very aware of taking their medication regularly and correctly.

“We’re now at a stage where we were in the early 1990s when we were waiting for new drugs to treat multidrug-resistant (MDR)-TB. We’ve used up our chances. We need to help the patients, but also protect the drugs.

Read: Drug-resistant strains make TB difficult to control

Schaaf, who was recently awarded the National Order of Mapungubwe (Silver) by President Jacob Zuma for his groundbreaking work on drug-resistant TB, says doctors need to have a better understanding of TB treatment beyond managing drug-sensitive TB.

“We are not thinking carefully enough about what we are doing, largely because of ignorance.  If you’re only giving one, or too few effective drugs, resistance can easily develop.”

He said doctors and nurses also need to be very careful about monitoring whether the medication is working. Patients can become drug-resistant if they don’t take their treatment. However, it may also be that the patient was infected with a drug-resistant TB strain from the start.

“Sometimes when a patient fails to respond to ordinary TB treatment over six months, they’re put on the same medication again, adding only one drug. By doing this, they eventually become resistant to all TB drugs. This has caused a huge problem, and has led to cases of extensive drug-resistant TB (XDR-TB), which can be fatal.

Combination of effective drugs essential

Schaaf says a combination of effective drugs is essential. He suggests that at least four different effective drugs be prescribed for someone with drug-resistant TB.

“Rather start aggressively with several drugs, and then taper down when you have the final drug sensitivity results. You need the combination of drugs so that the drugs can protect each other from organisms with resistance mutations taking over. If one doesn’t work, the others may.” 

Schaaf’s work with children at Tygerberg Children’s Hospital, as well as Brooklyn Chest Hospital has proved that MDR-TB can be successfully treated. The children with MDR-TB in these hospitals boast a cure rate of 90%, compared to a 50-60% cure rate in adults with MDR-TB.

About 7% of children who display TB symptoms have drug-resistant or MDR-TB.

Treatment for MDR-TB is tough on children. They have to endure painful injections and stay in hospital for up to six months to make sure they get their injectable drugs and are culture-negative for TB. But the medication can be life-saving. There may also be good news ahead for children with MDR-TB.

Child-friendly treatment

“With the recent development of a number of new drugs against TB, which should be available in the next few years, we hope to get rid of the injectable drugs,” says Schaaf.

Together with colleagues from the Desmond Tutu TB Centre at the Department of Paediatrics and Child Health, Schaaf is working on a study to improve drug dosaging and develop more child-friendly treatment for children. 

Read: Better treatment for babies with TB

“Professor Schaaf starts with the best interests of the children at heart. He has developed interventions and tested them and found the best way to go forward. Through this he has become a world expert in MDR-TB,” says Professor Mariana Kruger, head of the Department of Paediatrics and Child Health at Stellenbosch University.

Schaaf frequently advises clinicians all over the world. He also played a role in getting the World Health Organisation to change their recommendations for the correct TB drug dosages for children.

While appreciating the accolades, Schaaf says caring for his young patients is most rewarding.  “What I enjoy most is seeing the children get better.”

Read more:
Decrease in SA TB deaths
TB infections hard to diagnose in children

TB does not discriminate


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