Before treatment failure is presumed and a particular regimen discarded, every effort should be made to rule out causes other than drug resistance. Patients should be evaluated for correctable factors, such as:
Inappropriate dosing schedules,
Drug interactions that may reduce the efficacy of some of the ARV,
Non adherence due to side effects, and
Evidence of malabsorption.
Each of the above scenarios could result in sub-therapeutic drug levels and poor clinical response. In such cases, the regimen in question may be salvaged with palliative medication and/or patient education. If clinical assessment indicates the presence of treatment failure due to confirmed drug resistance, then the best approach is to switch to an entirely new regimen, choosing two or more drugs to which the patient is naïve as the second line drug regimen. Before changing to the second line drug regimen, the patient should go through the treatment readiness and education process again. This would need to be carefully monitored as some patients might hide their non-adherence.
Second-line antiretroviral therapy in adults and adolescents
The second line regimen for adults and adolescents includes the following drug combinations:
Abacavir 300 mg twice daily/Lopinavir/ritonavir 133.3/33.3 mg (Kaletra) 3 tablets twice a day and didanosine 200 mg. two tablets a day on an empty stomach
Note: ddI is easier to dose at 250-300 mg od for wt < 60 kg and 400 mg od for body wt > 60 kg.
Alternatively the following regimen can also be used:
Abacavir (ABC) 300 mg twice daily//Saquinavir/ritonavir (SQV 5X 200 mg or 1000 mg bd plus RTV one 100 mg cap bd) and didanosine 200 mg. two tablets a day
Note: ddI is easier to dose at 250-300 mg od for wt < 60 kg and 400 mg od for body wt > 60 kg.\