Videx, Videx EC – brand names

ddI – commonly-used name

didanosine – generic name

Videx tablets (original buffered version) and Videx EC capsules (time-release version) are different formulations of the same drug (didanosine). Because Videx EC is easier to take and does not contain a buffer (which can cause stomach upsets and drug interactions) it is the preferred formulation. The drug manufacturer discontinued the less-popular buffered version, Videx, in February 2006 in the US. Videx EC continues to be available.

Videx EC belongs to a class of HIV drugs called nucleoside reverse transcriptase inhibitors (NRTIs), also known as nucleoside analogs or “nukes.”

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.

The FDA also approved a generic version of Videx EC that is manufactured by Barr Laboratories.

Videx EC comes in:

• 125 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, the dose of Videx EC may need to be reduced.

Check with your child’s doctor 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.

As with all HIV drugs, it is important to take Videx EC as prescribed. Missing or skipping doses can cause your blood levels of the drug to fall too low and resistance can develop. When your virus becomes resistant to an HIV medication, that drug may stop working.

Videx EC can be used if you are beginning treatment for the first time.

You may be able to use Videx EC if you have developed resistance to other NRTIs, such as Epivir (lamivudine or 3TC).

Your doctor can run a resistance test to help determine whether Videx EC is likely to work 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).

Resistance to Videx EC is unlikely to cause resistance to Retrovir (zidovudine or AZT) or Zerit (stavudine or d4T).

Sometimes taking more than one medication can cause drug interactions. Consult your doctor or pharmacist for specific dosing instructions regarding your drugs (including methadone) and Videx EC.

Some drugs should not be taken with Videx EC, such as Hivid, Viread (tenofovir), Truvada, ribavirin, and Zerit. You should also avoid using alcohol while taking Videx EC.

Videx EC plus Viread plus Sustiva (efavirenz), Viramune (nevirapine), or Rescriptor (delavirdine) should not be used together. If you are taking Reyataz (atazanavir), it should be taken two hours before or one hour after Videx EC.

Several medications can make the side effects of Videx EC worse, such as hydroxyurea. Taking certain drugs can also change the amount of each drug in your blood. Your doctor may need to adjust the doses of your drugs to avoid side effects or under- or overdosing.

Be sure your doctor 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.

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 doctor for advice. Do not just stop taking your medication.

• Diarrhea
• Nausea
• Headaches
• Insomnia (trouble falling or staying asleep)

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 doctor 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.

If you are experiencing persistent, unusual, or serious side effects, call your doctor 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 pivotal study, ACTG 175, 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.

Check with your doctor 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 doctor know right away so you can be evaluated and, if necessary, treated.

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2		Monno, L., et. al. (1999). Comparison of once and twice daily dosing of didanosine in combination with stavudine for the treatment of HIV-1 infection. Antiviral Therapy, 4(4). 195-202.
3		Seidlin, M., et. al. (1992). Pancreatitis and pancreatic dysfunction in patients taking dideoxyinosine. AIDS, 6. 831-835.
4		Vella, S., et. al. (1996). A randomized trial (ISS 901) of switching to didanosine versus continued zidovudine after the diagnosis of AIDS. Journal of Acquired Immune Deficiency Syndromes, 12(5).462-469.