Question
I find it hard to take my meds at work – can I take a late dosage?
11 November 2011. Related: Adherence, All topics, Living with HIV long-term.
Because of work, I find it hard to take my meds at the same time every day. I usually take my Truvada within a 1 hour window (9.30 to 10.30) but my effavirenz is sometimes 4 hours later then the usual (sometimes not till 1 in the morning). Will this have an effect on resistance and effectiveness of the treatment?
Answer
I can understand that it can be difficult at times, especially at work, to follow and maintain a routine. Taking medication everyday and on time is very important because the drugs has to be kept at enough level to keep HIV under control, all of the time. Missing or late dosage means you will not absorb enough of the drugs for it to work properly and you can develop resistance.
There is usually a window period of about 1 or 2 hour that is still okay and all combination drugs are flexible enough to allow this widow period. The odd occasion of missing or being late with a dose (say once a month) may not make very much difference but do make sure it does not become too regular.
If your viral load is currently undetectable and has been this low for more than 6 months, the combination of efavirenz and truvada probably had sufficient flexibility for you to sometimes be up to four hours late with the efavirenz.
The two drugs in truvada will cover any short period when efavirenz levels are low, but efavirenz all is pretty good at having a buffer level at the end of each dose, so should hopefully not drop this low anyway.
The best way to avoid resistance is to take all your medications on time, everyday and also to follow any diet restriction (for example with or without food). One suggestion is for you to have a bleeper/timer with you all the time or perhaps you could ask one of your close friend or a family member to also remind you.
I include a link for you based on resistance, there you will find all the necessary information and hope that reading this will help you to understand and be informed about HIV.
The FOTO study (Five-On Two-Off) reported that in a small group of people with an undetectable viral load there was no viral rebounds over one year from missing the weekend doses of Atripla. This study was specific to these drugs (ie efavirenz, tenofovir and FTC).
Although that study is interesting, it is still probably better to stick to daily dosing. The caution about letting the window period for each dose be out by longer – by five hours for example – is that it might be more difficult to remember whether you have taken your meds each day. The routine is a pretty good adherence support in itself.
Before routinely extending the dosing by five hours it would be good to confirm drugs levels with a drug level blood test. Some people do not have high levels of efavirenz at 24 hours after the dose and it would be better to check this rather than find out months later that you have developed resistance.
Reference: Cohen C et al. The FOTO study: The 48 week extension to assess durability of the strategy of taking efavirenz, tenofovir and emtricitabine Five days On, Two days Off (FOTO) each week in virologically suppressed patients. 5th IAS Conference, 2009. Abstract MOPEB063.
http://library.iasociety.org/AbstractView.aspx?confID=2009&abstractId=3046
Since efavirenz reaches a constant concentration in the body after 5 days and takes several days to reach a level where it is not supressing HIV in most people I see no reason to stick to a 1-2 hour window for efavirenz as a rule. Once a day any time roughly in the same part of the day should be sufficient. The proof of the pudding is in the eating so to speak, ie does viral load stay undetectable? If it does, then no worries.
Also, if this combination is inconvenient for work reasons, perhaps an alternative might be more convenient (and just as good)?
– matt