Question
How often can I miss a dose?
9 June 2008. Related: Adherence, All topics, Resistance.
Hi, I have been on Sustiva/Truvada for 7 months and only missed 1 dose.
In your opinion how often could you safeley miss a dose? Not intending to purposely miss doses just a question really. Thanks!
Answer
I have a very traditional opinion and will have to say that you cannot miss doses safely.
The thing is that HIV does not mutate selectively, it does it randomly. Hense missing a dose is like a Russian roulette. During the period when the virus can replicate (as there is not enough medication to supress it in your body), it can mutate in such a way, that it becomes resistant to the medication, but it also can mutate in a way that it does not become resistant.
Hence every missed dose is a potential resistance provoker and it is more true with the non-nucleoside reverse transcriptase inhibitors (Sustiva and Viramune) than with the protease inhibitors.
At the same time, as I mentioned before, not every missed dose will by default lead to resistance, but, again, less is better.
Hi GK.
Where do you live? I’m asking because in most places ARVs are free.
Not taking your meds for a few weeks isn’t ideal. However, even if there may be some viral rebound this does not mean that you will become resistant to the meds. Once you restart them, your viral load will recover. That is if there’s a rebound. Having a very high CD4 is good.
It would help if you could talk to a doctor.
I’ve run out of finances and cannot afford to buy the tribuss treatment and won’t be able to for the next few weeks… it worries me a lot that I might become resistant to the medication. I have been taking it for 1 year and 6 months… and haven’t gone for my viral load test. Although there are no signs of my system showing weakness since my CD4 count was on 1000 the last time I took tests…. should I subtitute for something lesser? Will the medication have the same effect?
Hi Irese,
What meds are you taking?
The tablet is not easy to sallow.
Everyone forgets to take the meds at some time. If you skipped three doses in three years that’s good going, and it shouldn’t have a bad effect on your health.
But it’s not the same as missing three doses in a row. Whether it’s dangerous can depend on different things, such as what meds you are taking and if your viral load is undetectable.
You can find out more about missing doses here:
http://i-base.info/guides/starting/forgot-my-pills
Please let me know if you’d like more info.
Roy
I have been on treatment for three years and skipped three doses is it dangerous
The production of medication is really very heavy duty regulated. The companies do not have any interest to withold information about problems of this kind as the implications on the side of the regulatory bodies can be really severe. Severe to the extent that nowadays some regulatory bodies can remove a product from the market, and believe me the HIV is a quite lucrative market and no company would like to see their product disappear.
I worry about silly things like the manufacturer of the drug inadvertently making a bad batch of the meds and sending out a less efficacious batch of meds leading to people inadvertently taking weakened versions of their meds and widespread drug recalls etc (I’m sure it’s all computerized/formulated), but sometimes things happen…eg. tylenol scare a few years ago
Thanks John. I also think that missing one odd dose is unlikely to make any difference, especially after you have been on treatment for over six months.
There is not that much accurate data on the risks though because most adherence studies do not use standarised approaches and definitions, even for how ‘adherence’ is defined – ie a missed dose, a late dose etc.
The frequently quoted goal of 95% adherence was from a study in 1998 by Patterson and colleagues using nelfinavir (ie an unboosted PI). However 22% of people with >95% adherence still didn’t get an undetectable viral load – probably related to the potency of the drugs used and pre-existing resistance and other factors.
That study is out of date for many reasons, but I still support the goal for close to 100% adherence all the time – and not to worry if you miss an occasional dose.
More recent research (Bangsberg et al) has suggested that the risk of resistance with less than optimal adherence is likely to differ by the class of HIV drugs that are used.
References:
Patterson et al. Adherence to protease inhibitor therapy and outcomes in patients with HIV infection. Ann Intern Med. 2000 Jul 4;133(1):21-30.
http://www.ncbi.nlm.nih.gov/pubmed/10877736 J Antimicrob Chemother. 2004 May;53(5):696-9. Epub 2004 Mar 24.
Bangsberg et al. Paradoxes of adherence and drug resistance to HIV antiretroviral therapy.
http://www.ncbi.nlm.nih.gov/pubmed/15044425?dopt=Abstract
But studies show that 95% adherence is as good as 100%. And with this combo, missing the odd dose will mean nothing important because the drugs stay in your body at such a high level after the first 5 days that eg missing 1 dose a month will make no difference..
Respect. keep up the good work