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AIDSinfo Drug Database

AIDSinfo Drug Database

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Didanosine  Audio icon

Brand Name: Videx EC, Videx
Other Names: ddI, ddl EC, delayed-release didanosine, dideoxyinosine, enteric-coated didanosine
Drug Class: Nucleoside Reverse Transcriptase Inhibitors
Approved Use: Treatment of HIV Infection

Drug Image:
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Didanosine 125
Didanosine 200
Didanosine Capsule 250
Didanosine Capsule 400
Chemical Image:
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Molecular Weight: 236.23


Didanosine can cause serious, life-threatening side effects. These include pancreatitis (inflammation of the pancreas), lactic acidosis (buildup of lactic acid in the blood), and liver problems. The combination of didanosine and stavudine (another HIV medicine; brand name: Zerit) should be used with caution in pregnant women because of the risk of lactic acidosis.

Contact your health care provider right away if you have any of the following symptoms that could be signs of pancreatitis:

  • Stomach pain.
  • Swelling of your stomach.
  • Nausea.
  • Vomiting.
  • Fever.

Contact your health care provider right away if you have any of the following symptoms that could be signs of lactic acidosis:

  • Feeling very weak or tired.
  • Unusual (not normal) muscle pain.
  • Trouble breathing.
  • Stomach pain with nausea and vomiting.
  • Feeling cold, especially in your arms and legs.
  • Feeling dizzy or lightheaded.
  • Fast or irregular heartbeat.

Contact your health care provider right away if you have any of the following symptoms that could be signs of liver problems:

  • Yellowing of your skin or the whites of your eyes (jaundice).
  • Dark-colored urine.
  • Loss of appetite.
  • Nausea.
  • Vomiting, including vomiting blood.
  • Easy bruising or bleeding.
  • Swelling of your stomach.
  • Pain on the right side of your stomach.
  • Dark-colored bowel movements.

While taking didanosine, it is important to keep all of your appointments with your health care provider.

What is didanosine?

Didanosine is a prescription medicine approved by the U.S. Food and Drug Administration (FDA) for the treatment of HIV infection in adults and children 2 weeks of age and older. Didanosine is always used in combination with other HIV medicines.

Didanosine belongs to a class (group) of HIV drugs called nucleoside reverse transcriptase inhibitors (NRTIs). NRTIs block an HIV enzyme called reverse transcriptase. (An enzyme is a protein that starts or increases the speed of a chemical reaction.) By blocking reverse transcriptase, NRTIs prevent HIV from multiplying and can reduce the amount of HIV in the body. 

HIV medicines can’t cure HIV/AIDS, but taking a combination of HIV medicines (called an HIV regimen) every day helps people with HIV live longer, healthier lives. HIV medicines also reduce the risk of HIV transmission. If you are taking HIV medicines, including didanosine, don’t cut down on, skip, or stop taking them unless your health care provider tells you to. 

What should I tell my health care provider before taking didanosine?

Before taking didanosine, tell your health care provider:

  • If you are allergic to didanosine or any other medicines.
  • If you have or have ever had pancreatitis (inflammation of the pancreas).
  • If you have or have ever had kidney problems.
  • If you have or have ever had liver problems, including hepatitis.
  • If you drink alcoholic beverages.
  • If you take a medicine called stavudine (brand name: Zerit).
  • If you have or have ever had peripheral neuropathy (numbness, tingling, or pain in your hands or feet).
  • If you have any other medical conditions.
  • If you are pregnant or plan to become pregnant. Whether didanosine can harm an unborn baby is unknown. The combination of didanosine and stavudine (another HIV medicine; brand name: Zerit) should be used with caution during pregnancy and is recommended only if the potential benefit clearly outweighs the potential risk. Talk to your health care provider about possible risks with taking didanosine when pregnant.
  • If you are breastfeeding or plan to breastfeed. Do not breastfeed if you are infected with HIV or are taking didanosine.
  • If you are using hormone-based birth control (such as pills, injections, or implants).
  • About other prescription and nonprescription medicines, vitamins, nutritional supplements, and herbal products you are taking or plan to take. Didanosine may affect the way other medicines or products work, and other medicines or products may affect how didanosine works. Taking didanosine together with certain medicines or products may cause serious, life-threatening side effects. 

How should I take didanosine?

Didanosine comes in capsule form for use in adults and children 6 years of age or older who can safely swallow capsules and weigh at least 20 kg. The capsules come in 4 strengths, all under the brand name Videx EC:

  • 125-mg, 200-mg, 250-mg, and 400-mg delayed-release capsules, containing enteric-coated beadlets.

Didanosine also comes in a powder to mix with water to create an oral solution. An oral solution is a mixture of a medicine and a liquid that can be taken by mouth. The powder for oral solution can be used in adults and in children 2 weeks of age and older. The powder for oral solution comes in two strengths, both under the brand name Videx:

  • 4-ounce glass bottle containing 2 g of didanosine.
  • 8-ounce glass bottle containing 4 g of didanosine.

Take didanosine according to your health care provider’s instructions.

Both didanosine capsules and didanosine oral solution should be taken on an empty stomach. Do not take didanosine with food. Take didanosine oral solution at least 30 minutes before or 2 hours after you eat. Swallow the didanosine capsule whole; do not open it.

Some medicines should not be taken at the same time of day that you take didanosine. Talk to your health care provider about other medicines that you take.

Always take didanosine in combination with other HIV medicines.

If you take too much didanosine, contact your health care provider or local poison control center (1-800-222-1222) right away, or go to the nearest hospital emergency room.

For more information on how to take didanosine, see the FDA drug labels for didanosine capsules (brand name: Videx EC) and didanosine powder for oral solution (brand name: Videx), from DailyMed. (DailyMed is a federal website that includes the most recent drug labels submitted to FDA.)

What should I do if I forget a dose?

If you miss a dose of didanosine, take the missed dose as soon as you remember it. But if it is almost time for your next dose, skip the missed dose and just take your next dose at the regular time. Do not take two doses at the same time to make up for a missed dose.

What side effects can didanosine cause?

Didanosine may cause side effects. Most side effects from didanosine are manageable, but a few can be serious. Serious side effects of didanosine include pancreatitis (inflammation of the pancreas), lactic acidosis (buildup of lactic acid in the blood), and liver problems. (See the WARNING above.)

Other possible side effects of didanosine include:

  • Changes in body fat (including gain or loss of fat).
  • Vision changes.
  • Damage to the nerves outside the brain and spinal cord (peripheral neuropathy). Symptoms include numbness, tingling, or pain in your hands or feet. 
  • Immune reconstitution inflammatory syndrome (IRIS), a condition that sometimes occurs when the immune system begins to recover after treatment with an HIV medicine. As the immune system gets stronger, it may have an increased response to a previously hidden infection.

Tell your health care provider if you have any side effect that bothers you or that does not go away.

These are not all the possible side effects of didanosine. To learn more about possible side effects of didanosine, read the drug label or package insert or talk to your health care provider or pharmacist.

The AIDSinfo fact sheet on HIV Medicines and Side Effects also includes information that may apply to didanosine.

You can also report side effects to FDA at 1-800-FDA-1088 (1-800-332-1088) or online at


How should didanosine be stored?

  • Store didanosine capsules in a tightly closed container at 59°F to 86°F (15°C to 30°C).
  • Store bottles of didanosine powder in a tightly closed container at 59°F to 86°F (15°C to 30°C). Once the didanosine powder is mixed with water, the solution may be stored up to 30 days in a refrigerator at 36°F to 46°F (2°C to 8°C). Any solution left after 30 days should be thrown away.
  • Do not use didanosine if the original seal over the bottle opening is broken or missing.
  • Throw away didanosine that is no longer needed or expired (out of date). Follow FDA guidelines on how to safely dispose of unused medicine.
  • Keep didanosine and all medicines out of reach of children.

Where can I find more information about didanosine?

More information about didanosine is available:

Manufacturer Information

Bristol-Myers Squibb

The above Patient Version drug summary is based on the following FDA label(s): Capsule (delayed release); Powder (for solution).

Last Reviewed: January 4, 2016

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