Videx EC

Common Name: didanosine or ddI

Brand Name: Videx & Videx EC

Class: nucleoside analogs (also called nucleoside reverse transcriptase inhibitors, NRTIs or nukes)

Standard dose: One 400 mg enteric-coated (Videx EC), delayed-release capsule once a day, with adjustments for weight, kidney impairment, and when combined with Viread, Truvada, or Atripla. (Also available in 125 mg, 200 mg, and 250 mg capsules.) Videx is also available as a buffered powder for oral solution. Take Videx and Videx EC strictly on an empty stomach (unless taking with Viread), one hour before or two hours after food or drink, except water. Approved for children weighing at least 44 pounds. Take missed dose as soon as possible, unless it is almost time for your next dose. Do not double up on your next dose. Generic Videx EC is available.

AWP: $425.42 / month for Videx EC 400 mg capsules (generic enteric-coated $368.72 / month)

Manufacturer contact: Bristol-Myers Squibb,
www.bmsvirology.com, 1 (800) 272-4878

Potential side effects and toxicity: Peripheral neuropathy (tingling, burning, numbness or pain in the hands or feet) may go away once Videx is stopped, but can be painful and permanently debilitating if not treated in time. It occurs more frequently when used with Zerit. Upset stomach, diarrhea, headache, and, more rarely, pancreatitis (inflammation of the pancreas) have also been reported. Pancreatitis can be life-threatening and may cause pain in the stomach and back, along with nausea, vomiting, and blood in the urine. Risks for pancreatitis include higher than recommended doses of NRTIs, advanced HIV, and alcohol use. Stop all HIV medications and see a health care provider right away. Other possible toxicities include eye changes and optic neuritis. Have periodic eye exams by someone who is aware you are HIV-positive. Increased uric acid levels (indicating a number of disorders, including kidney damage and metabolic diseases), and insomnia are other potential side effects. Rare but potentially serious toxicity with all NRTIs: enlarged fatty liver (hepatomegaly with steatosis) and lactic acidosis (accumulation of lactate in the blood and abnormal acid-base balance). Lactic acidosis may cause persistent fatigue, abdominal pain or distension, nausea/vomiting, difficulty breathing or shortness of breath, and enlarged fatty liver. People with a history of peripheral neuropathy, pancreatitis, or heavy alcohol use should avoid Videx. Body fat redistribution/accumulation has also been reported with Videx.

Potential drug interactions: Videx levels are increased with Viread (a drug also found in Truvada and Atripla); therefore, use with caution and monitor closely when taking Viread, Truvada, or Atripla with Videx or Videx EC to avoid Videx-related toxicity, including neuropathy. The combined use of Videx and Retrovir (zidovudine, AZT), Zerit (stavudine, d4T), or hydroxyurea may increase risk of peripheral neuropathy. Either Videx or Videx EC taken with Zerit increases the risk of facial wasting, or lactic acidosis. Combining Videx with Zerit, hydroxyurea, alcohol, ganciclovir, valganciclovir, or intravenous (not inhaled) pentamidine may increase risk of pancreatitis. Do not take with ribavirin or allopurinol. Also, ganciclovir substantially increases Videx levels, and is generally recommended not to be taken together. If there is no alternative to ganciclovir, use it with caution and monitor for Videx toxicity. Videx oral solution should be taken on an empty stomach one hour before or two hours after protease inhibitors, Tagamet (cimetidine), ketoconazole, itraconazole, and dapsone, and one hour apart from Rescriptor, while Videx EC can be taken with them, but still on an empty stomach. With Viread, it may be taken with a light snack (low-fat, 373 calories). Methadone decreases Videx powder concentrations significantly and should not be used together, but if necessary, the Videx EC formulation should be used.

Tips: Study indicates Videx EC (compared to Videx) may have lower risk of peripheral neuropathy. Swallow the capsules whole. The capsules eliminate the bad taste and texture of the tablets and the enteric coating reduces diarrhea. If you have reduced kidney function, you may require a lower dose. Notify your doctor right away if peripheral neuropathy is suspected. Please see package insert for more complete potential side effects and interactions.

Doctor

Videx (didanosine, known to most as ddI) was approved for use in HIV infection in 1991. This was the second antiretroviral drug produced and it was usually given after taking AZT and no longer responding to it. This approach, called sequential monotherapy, was done for several years until studies showed that combination therapies of either two nucleosides or the now standard three-drug approach were more durable. Videx cannot be absorbed in an acid environment, but there is a capsule available that allows the drug to be absorbed after it passes through the stomach. A generic form of Videx capsules was also approved for sale in the U.S. in 2004. Videx is rarely used at this point -- there are several side effect issues noted that have limited the interest in using this agent -- including peripheral neuropathy, hepatitis, pancreatitis, and lipodystrophy. Early on, when tenofovir [Viread] first came out, we learned that this specific combination had additional side effects, leading clinicians to avoid that combination. Finally, an increased risk of myocardial infarction (heart attack) was found with the use of Videx (as is seen with abacavir) in the D.A.D. observational study. Therefore, it is clear why this drug is rarely used and listed as an acceptable but inferior option by the DHHS 2009 guidelines. -- Cal Cohen, M.D.

Activist

Once considered a major improvement over AZT, this drug now has little left to recommend it. It cannot be taken with food -- which can be a huge obstacle to adherence. It can also cause crippling neuropathy, and potentially fatal pancreatitis and lactic acidosis. Given these limitations, it's rarely used anymore -- which is what can make it useful as an add-on drug for patients in deep salvage who have developed resistance and burned through all the other meds. -- Jeff Taylor