Updated March 2010
Videx, Videx EC – brand names
ddI – commonly-used name
didanosine – generic name
Videx EC belongs to a class of HIV drugs called nucleoside reverse transcriptase inhibitors (NRTIs), also known as nucleoside analogs or “nukes.”
This drug was originally available as a tablet called Videx. Videx tablets were discontinued and replaced by Videx EC, which is an easier-to-take capsule version of the same drug.
Videx EC and the other NRTIs block reverse transcriptase, a protein that HIV needs to make more copies of itself. This may slow down HIV disease.
The Food and Drug Administration (FDA) has approved Videx EC for use in combination with other HIV drugs for the treatment of HIV infection in adults and children weighing more than 44 pounds. A powdered version of Videx is approved for children two weeks and older.
The FDA also approved a generic version of Videx EC that is manufactured by Barr Laboratories.
Videx EC comes in:
- 125 milligram (mg), 200 mg, 250 mg, and 400 mg capsules (capsules should be swallowed whole, not chewed)
Dosing depends on body weight:
- For people weighing more than 132 pounds, the dose is one 400 mg capsule once a day
- For people weighing less than 132 pounds, the dose is one 250 mg capsule once a day
Videx EC must be taken on an empty stomach, one hour before eating or two hours after a meal. Videx EC should be taken with water. It should not be taken with acidic juices, soda, or milk.
If you have liver, kidney, or pancreas problems, or peripheral neuropathy, tell your healthcare provider. Your dose of Videx EC may need to be reduced.
Check with your child’s health care provider for children’s dosing and administration. (There is a powdered formulation available for children.)
Videx EC must be used with other HIV medications to treat HIV.
If you miss a dose, take it as soon as possible. If it is almost time for the next dose, skip the missed dose and continue your regular dosing schedule.
As with all HIV drugs, it is important to take Videx EC as prescribed by your health care provider. Missing or skipping doses can cause your blood levels of Videx EC to fall too low and the virus can become resistant to it. This may cause Videx EC and other HIV drugs you are taking to stop working.
Videx EC can be used if you are beginning treatment for the first time or if you have taken HIV drugs in the past.
You may be able to use Videx EC if you have developed resistance to other NRTIs, such as Epivir (lamivudine or 3TC).
You and your health care provider can use resistance testing and your treatment history to guide the use of Videx EC and to determine which drugs are likely to work best for you.
If your virus develops resistance to Videx EC then it may stop working or not work as well for you.
Videx EC-resistant HIV may also be resistant to Hivid (zalcitabine or ddC).
Videx EC can interact with other medications. Taking Videx EC with certain drugs can change the amount of each drug in your blood. Your health care provider may need to either adjust the doses of your drugs to avoid under- or overdosing or change the drugs you currently take.
Videx EC should not be taken with:
- Zyloprim, Lopurin, and Aloprim (allopurinol)
- Copegus, Rebetol, Ribasphere, and Virazole (ribavirin)
- Videx EC plus Viread (tenofovir) plus Sustiva (efavirenz), Viramune (nevirapine), or Rescriptor (delavirdine) should not be used together
- Avoid using alcohol while taking Videx EC
Several medications can make the side effects of Videx EC worse, such as Viread and Zerit. It may be best to avoid combining Videx EC with either of these drugs
If you are taking Reyataz (atazanavir), it should be taken two hours before or one hour after Videx EC.
Methadone can decrease the amount of Videx EC in the bloodstream. This can result in your HIV drug regimen being less effective against HIV, which can cause drug resistance.
Because there are many possible drug interactions with Videx EC, it is very important to go over all your medications with your health care provider. Be sure your health care provider knows about all the medications you are taking (including over-the-counter, prescription, street drugs, and herbs), even if you only use them occasionally.
For more information and additional resources to check interactions between
the particular drugs you are taking, see our info sheet on
drug interactions or go to:
Videx EC can cause side effects, especially if taken with Zerit. However, most Videx EC side effects are likely to be temporary and go away as your body adjusts to the medication. If you are experiencing any of the side effects listed below, call your health care provider for advice. Do not just stop taking your medication.
- Stomach pain
More serious side effects:
- Peripheral neuropathy (numbness, pain, or tingling, especially in your feet and hands).
- Pancreatitis (inflammation of the pancreas) can be a serious threat to your health. Symptoms include sudden or sharp pains in the middle of the abdomen, fever, nausea, or vomiting. Notify your health care provider immediately if you develop symptoms of pancreatitis. Pancreatitis is more common in older patients, people who have had it before, and those with kidney problems.
- An increase of lactic acid in the blood ( lactic acidosis), an enlarged and fatty liver, and liver failure have been reported in people using NRTIs. Lactic acidosis is a rare but potentially fatal side effect. Symptoms include nausea, vomiting, or stomach pain; feeling very weak and tired; shortness of breath.
- Damage to the eyes. Because of this, you should have regular eye exams and report any changes in vision to your doctor right away.
- Lipodystrophy, which may include elevated blood sugar (glucose), elevated lipid levels ( cholesterol and triglycerides), and fat gain or loss in certain areas. The exact causes of lipodystrophy are not known, but may include HIV and/or HIV drugs. It is unclear if Videx EC will cause or impact symptoms of lipodystrophy. For more information on lipodystrophy, see our info sheet.
- Non-cirrhotic portal hypertension: This rare, but serious complication in the liver can result in serious bleeding and, in some cases, death. People on Videx EC should be monitored for portal hypertension.
If you are experiencing persistent, unusual, or serious side effects, call your health care provider right away.
Videx and Videx EC have been studied in both men and women. The effectiveness and side effects seem very similar in both sexes.
An early study called ACTG 175, researchers compared Retrovir alone, Videx alone, Retrovir plus Videx, and Retrovir plus Hivid. This study included 18% women, or about 444 women out of 2,467 total participants.
In this trial, the two combination regimens and Videx alone all worked better than Retrovir alone. Videx alone and Videx plus Retrovir both slowed the decline of CD4 cells and reduced the risk of progression to AIDS or death.
In terms of side effects, studies of medical records indicate that women (especially overweight women) taking NRTI drugs, including Videx, are more likely than men to develop elevated lactic acid levels and enlarged fatty livers. Some studies suggest that women are also more likely than men to develop pancreatitis.
Studies have shown that pregnant women who use HIV drugs can greatly reduce the risk of passing HIV on to their babies. Videx EC has been used during pregnancy without any significant negative effect to mother or baby; however, long- term effects on the child are not known.
There have been a few cases of fatal lactic acidosis in pregnant women taking Videx plus Zerit. In 2001, the FDA issued a warning about use of this drug combination by pregnant women.
Pregnant women should not take Videx EC and Zerit together.
An Antiretroviral Pregnancy Registry has been established to collect
information on pregnant women who take HIV drugs, including Videx EC. If you
are pregnant and taking Videx EC or other HIV drugs, your health care provider
can register you by calling 1-800-258-4263 or going to
It is not known whether Videx EC passes into breast milk. HIV+ women should not breast-feed because their babies could be infected with HIV through the breast milk.
Check with your health care provider about the best treatment options for you and your baby if you are thinking of getting pregnant.
Click this link for more information about pregnancy.
People who are starting HIV treatment for the first time may develop Immune Reconstitution Syndrome or IRS (also called Immune Reconstitution Inflammatory Syndrome or IRIS). IRS can happen as a result of the immune system getting stronger and responding to an HIV-related infection such as Mycobacterium avium infection (MAC), cytomegalovirus (CMV), Pneumocystis jirovecii pneumonia (PCP), or tuberculosis (TB). People may have been treated for these infections in the past or not even know they have them. If you notice any unusual symptoms soon after starting HIV drugs for the first time, let your health care provider know right away so you can be evaluated and, if necessary, treated.