Q and A


Can I be late with Atripla?

Can taking my daily pill of Atripla an hour later than my usual time make me resistant to the medication?


Taking meds late can increase the chance of resistance. The three drugs in Atripla generally have high enough concentrations after 24 hours for this not to be a big risk if it happens very occasionally (once a month), and probably still a small risk if it happens more often.

Taking antiretrovirals as close to the prescribed time as possible is important. This is to keep good drug levels in your body and keep the pressure on HIV replication. The more HIV replicates, the higher the chance of the virus mutating. Mutations lead to resistance.

Some classes of medications are more


  1. Lisa Thorley

    Hi Bill,

    Though there is a possibility that this can happen, (please see the following http://i-base.info/qa/2234 ) it’s very rare. If you stop taking your medication you risk developing resistance to the Atripla as well as viral rebound, therefore this isn’t something that’s advised.

  2. Bill


    I read Atripla could get false positive to marijuana. I want to know how much time do i need to suspend the pills if i need normal laboratories.

  3. MARIO


  4. Rebecca McDowall

    Hi Mario,
    I’m very sorry to hear about your recent diagnosis. Do you have any support to help you deal with this?

    Before you start any treatment your doctor will need to run some tests to check how strong your immune system is (this is called a CD4 count test). Unless your CD4 count is low (under 200) you should have some time to learn about treatment before you need to start any meds. HIV is treated with meds called antiretrovirals (ARVs). Different people take different ARVs depending on their health, preferences and what is available. You can read about this treatment in our Introduction to combination therapy. Also, have a look at our Just diagnosed? page for advice about coming to terms with a new diagnosis.

  5. Rebecca McDowall

    Hi John,

    I’m glad to hear you are doing so well on treatment. Your doctor is right than most people take Atripla at night to avoid side effects. But if 2pm works better for you then it is fine to take it then. I wish you the best of luck with treatment!

  6. John

    I have been taking Atripla for 5 years now!!!!! as of January 6th 2013 my viral load is (less than 20 copies Undetectable) & (CD4 is 800) I have missed 4 doses in 5 years by accidentally falling asleep and waking up 7 hour later yes I did take it first thing when I woke up but as you can see my bloods are perfect. My doctor said Atripla has very long half life so that’s why it didn’t affect my levels. She did tell me that I could take Atripla during the day if I wanted to but most people take them at night because of sutsiva CNS side affects WHICH I HAVE HAD NO SIDE AFFECTS FROM ATRIPLA WHATSOEVER EVER. I now take the Attipla combo at 2pm everyday & I find that is a million times easier than say at 11pm tired and exhausted after work.

  7. Sean

    I have been on Atripla for three months now and have had labs drawn once. My viral load was nearly undetectable (2000) the bigger problem was my CD4 count which was really low. I took the pill 6 hours late once and I am not too concerned because of the half-life.

    I will stay on course because I do not want the risk of resistance. This drug is a miracle!

  8. Chria


    I need to ask something. I am on Stocrin and Truvada. I have been taking them exactly on time for about the last 2 months. I have only been on treatment for roughly 2 months.

    Last night I fell asleep and woke up 7 hours later and took them. I did phone my doctor and she said I must take them immediatley.

    This has been the first and only time that this has happend. Now I want to know if there is now a chance I have screwed everything up?

    Please can someone help with some answer?



  9. Simon Collins

    Thanks for posting this link, though I’m not sure this answer from Prof Gallant it is right for every situation.

    I’d be very careful about generalising anything about adherence, and I don’t think there is any data to say that anyone can safely and regularly be 5 hours late, with any combination, without that increasing the risk that they will develop resistance.

    Even now, only 70-80% of people using the drugs in Atripla (efavirenz, tenofovir/FTC) get viral load to undetectable in trials – and adherence is likely to be one of the reasons this is not 100%.

    I think that looking in more detail about the window that you have to take your drugs in is both practical and useful, and before giving a general comment, I’d want to know whether someone was just starting treatment, or whether they already had an undetectable viral load that had been steady for many months.

    When starting treatment, I think being as accurate to the time as possible is still important with all HIV drugs. Even though some recent drugs are generally better at having a safer ‘buffer’ level at the end of the dose period, there are still people who have low levels at the end of each dose.

    In Europe this decision to approve Atripla is that it is only used as a switch drug in people without related resistance in people who have had and undetectable viral load for over 3 months by taking efavirenz and Truvada as separate drugs.

    Also, as drug level monitoring is rarely used, there is no way of knowing on an individual level, if you are one of the people who has low levels at the end of the dosing period.

    When starting treatment, some people will have high viral loads and low CD4 counts, and will need everything they can get from treatment to get viral load down to undetectable levels.

    Also, aiming for the same time each day when starting treatment, is likely to make adherence a more routine part of your life – and easier not to miss any doses.

    After getting your viral load down to undetectable in blood (less than 50 copies/mL), it takes another few months to get undetectable levels in your lymph nodes (where at least 20 times as much virus lives). After this, when your HIV drugs have done the bulk of their first main job, you still need to continue treatment though to mainly catch and suppress that wakes up from sleeping cells.

    At this point, the impact of being a bit earlier or later with treatment is less likely to cause resistance, especially if those drugs generally have good levels at the end of the dose. This is the case with all the drugs in Atripla.

  10. Chris


    While I would agree with you regarding the ‘normal’ twice-daily regimens, I think Atripla is a bit more forgiving than this. Here is the opinion of Prof. Joel Gallant (who I greatly trust!) in response to this question:

    Dose timing for Atripla and Sustiva (Posted on Oct 5, 2007)


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