|5 and a half days with wrong regimen !
Feb 23, 2002
Following a switch from PI-containing HAART to NNRTI-HAART, a friend of mine inadvertently (due to poor transmission of information...) took (nevirapine (1/day) + norvir (2/day)), instead of the prescribed (Combivir + Nevirapine), for 5.5 days before realizing the error. The HAART switch was done at a time when his VL was undetectable (actually VL was undetectable since HAART was started one year ago). The decision to switch was motivated following enrollment in a "IL-2 trial". In your experience, do those 5.5 days on nevirapine "alone" pose a major threat to the long term efficacy of the whole NNRTI class? The patient, who is otherwise perfectly compliant, was immediately put back on his prior PI-containing scheme + nevirapine for 1 week, prior to resume the new scheme with (combivir + nevirapine). Do you expect a major risk of resistance developing over that period ? What about resistant strains being "archived" ? Does that necessarily worsens the long-term prognosis ?
Query from a (non-hiv specialist) doctor
(PS: I tried to send the same question yesterday, but was not sure whether it had gone through...Please disregard this query in case you already got it. Than you for considering this question in your forum)
Response from Dr. Little
No - I think the risk is extremely small. In general, nevirapine is started at 1 tab per day for 14 days, then with an increase to 1 tab twice daily indefinitely. After over a year of being completely suppressed, the viral load may well have still been undetectable the entire 5.5 day duration in question.
In terms of archived virus - in general, any time resistant virus is generated at a level that is sufficient to be detected by population based detection techniques (those that are routinely used in the non-research setting) - we would presume that it has been archived in various long lived T cell reservoirs and could be rapidly re-selected in the future if the appropriate selective drug pressure (use of a drug to which this archived virus is resistant) were restarted. However, in the 5.5 day case presented, I think the chances are really quite remote that there is any significant risk that resistant virus developed.
Three classes resistance
Drug Resistance Question
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