How the interaction occurs:
How this interaction occurs is not known.
What might happen:
When these medications are taken together, the levels of didanosine in your blood may increase. You may have more side effects from your didanosine. If you are taking these medicines with efavirenz or nevirapine, they may not work as well against your HIV infection.
What you should do about this interaction:
Your doctor may change the dose of your didanosine if you start or stop taking tenofovir. If you take the enteric coated capsule form of didanosine and either plain tenofovir or a combination product containing tenofovir with emtricitabine, you may take it with your tenofovir on an empty stomach or with a light meal. A light meal consists of less than 400 calories and less than 20% fat. If you take any other form of didanosine, you may still take it at the same time as your plain tenofovir or your combination tenofovir with emtricitabine, but you should take both on an empty stomach. The combination product containing tenofovir, emtricitabine, and efavirenz should be taken on an empty stomach.Let your healthcare professionals (e.g. doctor or pharmacist) know if you notice any new side effects from your didanosine, especially severe stomach pain with nausea and vomiting; or if you feel very weak, tired, or uncomfortable, cold, dizzy or lightheaded; or if you develop a slow or irregular heartbeat.Your doctor may want to perform some blood tests to see how your medicines are working.Your healthcare professionals may already be aware of this interaction and may be monitoring you for it. Do not start, stop, or change the dosage of any medicine before checking with them first.
1.Viread (tenofovir disoproxil fumarate) US prescribing information. Gilead Sciences, Inc. July, 2013.
2.Truvada (emtricitabine/tenofovir disoproxil fumarate) US prescribing information. Gilead Sciences, Inc. June, 2013.
3.Atripla (efavirenz/emtricitabine/tenofovir disoproxil fumarate) US prescribing information. Gilead Sciences, Inc. April, 2013.
4.Dear Canadian Healthcare Professional letter: Subject: New safety information regarding the co-administration of Videx and Viread, and either Sustiva or Viramune. Bristol-Myers Squibb Canada and Gilead June 9, 2005.
5.Videx EC (didanosine) US prescribing information. Bristol-Myers Squibb Company November, 2011.
6.Guo Y, Fung HB. Fatal lactic acidosis associated with coadministration of didanosine and tenofovir disoproxil fumarate. Pharmacotherapy 2004 Aug; 24(8):1089-94.
7.Blanchard JN, Wohlfeiler M, Canas A, King K, Lonergan JT. Pancreatitis treated with didanosine and tenofovir disoproxil fumarate. Clin Infect Dis 2003 Sep 1;37(5):e57-62.
8.Murphy MD, O'Hearn M, Chou S. Fatal lactic acidosis and acute renal failure after addition of tenofovir to an antiretroviral regimen containing didanosine. Clin Infect Dis 2003 Apr 15;36(8):1082-5.