In 2006, the first single-tablet combination regimen was approved for treating HIV infection. Little did we know that one pill-once a day would become the rule, not the exception. The drug Atripla combined three potent drugs for treating HIV: Efavirenz, Emtricitabine (or FTC) and Tenofovir. Efavirenz (Sustiva) was first approved in 1998 and quickly became one of the most widely used HIV drugs. In 2019, we now have at least 10 fixed-dose-combination tablets available for treating HIV. Most contain three drugs, some contain four (three active drugs and a booster) and some contain only two drugs, all combined into one tablet. They are all dosed once a day.
I remember quite vividly when Atripla was approved. Everyone wanted the ease and simplicity of just one pill once a day. But Everyone wasn’t going to get it. Obviously, there were some patients who had become resistant to either efavirenz, or FTC or tenofovir from previous use and so they would not be eligible for the single-pill combination. It would not work well for them. But a whole group of patients would not be able to take Atripla because of safety concerns. Safety concerns for who? We started a discussion about pregnancy in the last article. There’s good news and bad news.
The good news we discussed last time is that HIV medicines can protect an HIV+ mother from infecting her baby, during gestation, delivery and breast-feeding. The bad news is that some medicines can harm babies during development. Because of this, there are many drugs of all types that are not to be given to pregnant women. Drugs that cause harm to a developing fetus are called teratogens. So while HIV medicines could protect developing babies, we needed to know which ones are teratogens and not use them in pregnant women.
When Efavirenz was released, we had good reason to believe that it was a teratogen, increasing risk for a birth defect that disrupted normal development of the spinal cord . Efavirenz or Atripla would not be given to pregnant women. But since HIV treatment is chronic and life long, there was a concern of women taking the drug and later becoming pregnant while on it. A woman could be switched to a different treatment after becoming pregnant, but they don’t even