An article published in the media last weekend is causing undue panic with a title that suggests there are problems with the new ARV regimen. Intolerance is incorrectly assumed to mean resistance. Intolerance and resistance are two different things.
Resistance refers to a decrease in the effectiveness of a drug while intolerance is adverse (harmful or unfavourable) effects from a drug such as stomach irritation or drowsiness. Simply put, resistance means the drug is not working; intolerance means the drug could be working but is making a person feel ill.
The article is based on a report in the HTB South Bulletin that discusses a presentation that was given by researchers at the International Conference on Aids and STIs in Africa (Icasa) in December 2013.
Unfortunately, I was not able to trace the original Icasa presentation but based on HTB South article, the researchers report that at Lighthouse Trust in Lilongwe, by March 2013, of 4 808 people on the new ARV regimen (TDF/3TC/EFV ), 94 had to switch to another treatment which does not have EFV or efavirenz i.e. (TDF/3TC+NVP) . This gives an intolerance rate of two percent.
That means two percent of people who started the new regimen experienced unfavourable side effects and were switched to another drug combination. This calculation is made to ensure adequate stocks of alternative treatments.
Previously, the researchers had estimated intolerance at one percent. Other international studies have found similar findings) but this could because health workers may have been less confident about switching patients’ treatments, health workers not aware of the symptoms related to efavirenz or few patients presenting with complaints.
The side effects of efavirenz include drowsiness or insomnia, dizziness, vivid dreams and nightmares and loss of memory. The side effects are most likely to occur in the first two to four weeks of treatment, after which they tend to diminish markedly. Care must be taken to rule out other causes of neurological or psychiatric symptoms.
Unfortunately, phrases in the article such as “worse than anticipated”, “quandary”, “limbo” were unnecessary. There have been a number of studies on the intolerance of efavirenz that suggest intolerance between one and three percent.
Efavirenz is much better than d4T, lest we forget that d4T had an intolerance of 15 percent and caused wasting. It is crucial to have a good approximation of intolerance so that there are adequate stocks of drugs for those experiencing adverse side effects.