23.4 Why is drug resistance important for ART?
Blood levels of ARV drugs have to be maintained at optimal concentrations in order to be effective against HIV. Poor adherence to ART will result in low blood levels of ARV drugs, and these low concentrations will be unable to completely suppress viral multiplication. In these conditions, the virus can change in such a way that it resists the action of the drugs, even if drug blood levels return to normal, that is, even if the patient resumes good adherence to ART. Hence, drug-resistant viruses will multiply faster in a patient with a history of poor adherence, leading to the patient becoming sicker. In addition, drug-resistant HIV can be transmitted to other individuals for whom these drugs will not work either.
Whether a person living with HIV is infected with drug-resistant HIV can be confirmed at a hospital by specific blood tests. If this is the case, the regimen of drugs taken by that individual will have to be modified and new drugs prescribed. However, drug resistance is not without problems when it comes to HIV treatment, for two reasons. First, there are limited numbers of drugs available in Ethiopia. Secondly, it may be more difficult for a patient to maintain adherence to the drugs used to replace first-line ARV drugs to which HIV has become resistant, due to their increased side-effects and the larger number of tablets to be taken.
What are the consequences for a patient who has not adhered to their ART treatment and failed to respond to first-line drugs?
In general if patients needing ART treatment fail to adhere to their initial treatment, then HIV within these patients may develop resistance to their ARV drugs. If this patient is not prescribed other combinations of ARV drugs (which may be more difficult to adhere to), they will eventually become sick and develop AIDS-related symptoms.