POSITIVELY AWARE MARCH/APRIL 2011
brand name: Videx and Videx EC
common name: didanosine or ddI
class: Nucleoside analog reverse transcriptase inhibitor
(nucleoside analog, NRTI, or nuke)
manufacturer: Bristol-Myers Squibb | www.bms.com, (800) 321-1335
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: $442.42 / month for Videx 400 mg capsules (generic Virex EC $368.72 / month)
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 Videx is 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. Recent post-marketing surveillance has reported cases of non-cirrhotic portal hypertension (increased blood pressure in the vessels that connect to and from the liver) associated with the use of Videx EC. Symptoms (elevated liver enzymes, enlarged spleen, blood in vomit, and fluid collection in abdomen) may begin months to years after starting Videx EC. Routine doctor visits and lab tests will assist in early detection and prompt discontinuation of Videx EC. 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 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
Should not be taken with Viread, if possible. However, if co-administration is necessary, use Viread with caution and close monitoring, since Videx levels are increased with Viread (a drug also found in Truvada and Atripla). Dose adjust Videx or Videx EC when taking Viread, Truvada, or Atripla 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 and/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.
More information
Study indicates Videx EC compared to Zerit may have lower risk of peripheral neuropathy, but the rate found in clinical trials is still 12-34%. 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. See package insert for more complete information on potential side effects and interactions.
Doctor’s comments
Videx (ddI), approved in 1991, was our second antiretroviral drug. People often used it after AZT stopped working. Later, it was added to AZT in our primitive attempts at early combination therapy. It was a complicated drug to take, requiring twice-daily dosing on an empty stomach, and sometimes involving the use of powder formulations or the mixing of crushed tablets with antacids to improve tolerability. The new EC (enteric coated) formulation eliminates those problems, but this is no longer a drug with much of a purpose. Its resistance patterns overlap with the better tolerated tenofovir and abacavir, and it causes neuropathy, pancreatitis, and probably lipo-atrophy. More recently, questions have been raised about whether ddI might cause non-cirrhotic portal hypertension, an uncommon but serious and potentially fatal liver condition that doesn’t get better after you stop taking the drug. —Joel Gallant, MD, MPH
Activist’s comments
Originally hailed as an improvement over AZT, when used alone, Videx proved just as ineffective. Even in combination with other drugs, the problematic dosing on an empty stomach, the crippling neuropathy, pancreatitis, and lactic acidosis combined to make this drug an also-ran. The fact that it’s rarely used anymore can work in its favor—making it a useful add-on drug to salvage regimens for patients who’ve exhausted all other options. —Jeff Taylor
