Drug-resistant TB

Toby Capstickby Toby Capstick, Lead Respiratory Pharmacist & Member of the British Thoracic Society MDRTB Clinical Advice Service

Last night’s  Inside Out report for BBC One London Tackling drug-resistant TB in London described how tuberculosis is on the increase in London. A serious concern is that an increasing number of patients are being identified with strains of TB that are resistant to the most effective antibiotics used to treat the disease.

Rates of TB in the UK as a whole have remained relatively steady since 2005. They had risen over the previous two decades, in contrast to most other developed countries where TB rates had remained stable or had fallen. Public Health England reported that there were a total of 8,751 cases of TB in the UK in 2012, and resistance to at least one antibiotic was found in almost 1 in every 13 people diagnosed with TB.

Whilst levels of multidrug-resistant TB (resistance to the two most effective antibiotics) in the UK is currently relatively low – there were 81 reported cases in 2012 – it is important to understand the complexities, cost and difficulties of taking antibiotics to treat drug-resistant TB.

Drug-resistant TB is on the increase across the world. This is caused by use of inappropriate antibiotics, lack of monitoring of treatment, unavailability of TB medicines and patients stopping treatment early or missing doses for any reason. Pharmacists have a pivotal role in each of these areas to prevent resistance developing.

People diagnosed with the most common type of TB require a six-month course of treatment, initially with medication containing a combination of four different antibiotics, and this will cure them of the disease. However in people with drug-resistant TB, treatment requires up to five or six antibiotics to be taken for nearly two years (including daily injections for the first 6-8 months).

Increasing rates of multidrug-resistant TB is of concern partly because the drugs used are more complex and more expensive than those used to treat the most common type of TB, costing about £8,600 over 18 months compared to £260 for a standard 6-month treatment course.

If the first-choice antibiotic treatment doesn’t work for a patient, a second-choice treatment is selected.  These ‘second-line’ antibiotics are often less effective than ‘first-line’ antibiotics, which explains why more are required for a longer duration, and they have more, often severe, side effects.

Pharmacists have the expertise to advise on the appropriate use of these antibiotics, and monitoring blood tests to ensure they are used safely and effectively. We play an important role in the management of drug-resistant TB as incorrect treatment may result in further antibiotic resistance developing.

We are also able to support patients throughout treatment, advising on the importance of taking, and how to take, their medication, as well as monitoring, treating and preventing side effects of treatment.

The expertise of pharmacists is of paramount importance as many of the second-line antibiotics used to treat multidrug-resistant TB are currently not available in the UK, and have to be imported from abroad. Sometimes hospitals experience difficulties in obtaining these essential antibiotics to treat TB. These supply problems are relatively rare, but pharmacists are essential in ensuring the consistent supply of quality-assured medicines to ensure the successful treatment of TB.