“My doctor says I have resistance to (Drug X), but he is still prescribing it as part of my 3-drug ‘cocktail.’ Why would I still be on it if I’m resistant?”
That’s a very frequently asked question, regardless of the drug – AZT, Epivir, Viread, whatever. It demonstrates a lack of understanding about what “resistance” means. Even the phrase “I am resistant” is a problem. It is never the patient who is drug-resistant; it is the patient’s virus.
Basically, “resistance” means that Drug X is not completely doing its share in controlling the person’s HIV, because the virus has changed slightly (mutated). Thus, Drug X is not 100% effective as part of the cocktail, or HAART. However, that doesn’t mean Drug X isn’t doing anything at all. Despite partial resistance, it may still have some very useful activity.
A resistance panel (there are two kinds of tests) doesn’t show black/white or works/fails. It says whether resistance is present and how much – e.g., none, low, medium, or high. It should also state which mutations are present to enable resistance.
Some resistance, by itself, may not be enough reason to switch meds. The degree of resistance is important. If Drug X still works at an acceptable level – say, low resistance – then why change? Other considerations also may cause Drug X to be retained. What other drug options are available? What side effects are likely with another drug? Does switching predict disastrous future mutations? What will a change do to dosing requirements?
Of course, if viral load isn’t under acceptable control, then another HAART combination may be needed. The decision is a complex one: It is always based on more than having simple resistance.
This article appears in “The AC” Gen Y Magazine Debuts.