Didanosine is an antiviral medicine that prevents human immunodeficiency virus (HIV) from multiplying in your body.

Didanosine is used to treat HIV, the virus that can cause acquired immunodeficiency syndrome (AIDS). Didanosine is not a cure for HIV or AIDS.

Didanosine is for use in adults and children who are at least 2 weeks old.

Didanosine may also be used for purposes not listed in this medication guide.

Do not take didanosine together with allopurinol, ribavirin, or stavudine.

You may develop lactic acidosis, a dangerous build-up of lactic acid in your blood. Call your doctor or get emergency medical help if you have unusual muscle pain, trouble breathing, stomach pain, dizziness, feeling cold, or feeling very weak or tired.

This medicine can also cause severe or life-threatening effects on your liver or pancreas. Call your doctor at once if you have: severe pain in your upper stomach (may spread to your back), nausea and vomiting, fast heart rate, itching, loss of appetite, dark urine, clay-colored stools, or jaundice (yellowing of the skin or eyes).

Follow all directions on your prescription label and read all medication guides or instruction sheets. Use the medicine exactly as directed.

Take didanosine on an empty stomach, at least 30 minutes before or 2 hours after a meal. Do not take with food.

Shake the oral suspension (liquid) before you measure a dose. Use the dosing syringe provided, or use a medicine dose-measuring device (not a kitchen spoon).

Swallow the capsule whole and do not crush, chew, break, or open it.

Use all HIV medications as directed and read all medication guides you receive. Do not change your dose or dosing schedule without your doctor's advice. Every person with HIV should remain under the care of a doctor.

You will need frequent medical tests. Your vision may also need to be checked.

Store the tablets or capsules at room temperature in a tightly closed container, away from moisture and heat.

Store the liquid in the refrigerator. Throw away any leftover didanosine liquid that is more than 30 days old.

Usual Adult Dose for HIV Infection:

Delayed-release Capsules:
-Less than 60 kg: 250 mg orally once a day
-At least 60 kg: 400 mg orally once a day

Oral Solution:
Preferred dosing:
-Less than 60 kg: 125 mg orally twice a day
-At least 60 kg: 200 mg orally twice a day

For patients requiring once-daily dosing:
-Less than 60 kg: 250 mg orally once a day
-At least 60 kg: 400 mg orally once a day

Use: In combination with other antiretroviral agents, for the treatment of HIV-1 infection

Usual Pediatric Dose for HIV Infection:

Delayed-release capsules:
20 to less than 25 kg: 200 mg orally once a day
25 to less than 60 kg: 250 mg orally once a day
At least 60 kg: 400 mg orally once a day

Oral solution:
2 weeks to 8 months: 100 mg/m2 orally twice a day
Older than 8 months: 120 mg/m2 orally twice a day
-Maximum dose:
---Less than 60 kg: 125 mg/dose
---At least 60 kg: 200 mg/dose

Comments:
-Oral solution: The adult dose should not be exceeded.

Use: In combination with other antiretroviral agents, for the treatment of HIV-1 infection

Panel on Antiretroviral Therapy and Medical Management of Children Living with HIV Recommendations:
Delayed-release capsules:
6 years or older:
20 to less than 25 kg: 200 mg orally once a day
25 to less than 60 kg: 250 mg orally once a day
At least 60 kg: 400 mg orally once a day

Oral solution:
2 weeks to less than 3 months: 50 mg/m2 orally every 12 hours
3 to 8 months: 100 mg/m2 orally every 12 hours
Older than 8 months: 120 mg/m2 (dose range: 90 to 150 mg/m2) orally every 12 hours
-Maximum dose:
---Less than 60 kg: 250 mg/day
---At least 60 kg: 400 mg/day

Comments:
-This drug is not recommended due to significant toxicity and availability of safer agents.
-Viral suppression has been effective in therapy-naive patients (3 years or older) administered 240 mg/m2 orally once a day (either formulation).
-BSA-based dosing should not exceed maximum adult dose.
-Combination therapy with tenofovir disoproxil fumarate (DF) is not recommended.
-Current guidelines should be consulted for additional information.

You should not use didanosine if you are allergic to it. Do not take didanosine together with allopurinol, ribavirin, or stavudine.

Tell your doctor if you have ever had:

• liver disease or pancreatitis (didanosine can cause severe or life-threatening effects on your liver or pancreas);

• kidney disease (or if you are on dialysis);

• numbness or tingling in your hands or feet, including Raynaud's syndrome; or

• if you drink large amounts of alcohol.

You may develop lactic acidosis, a dangerous build-up of lactic acid in your blood. This may be more likely if you have other medical conditions, if you've taken HIV medication for a long time, or if you are a woman. Ask your doctor about your risk.

Tell your doctor if you are pregnant, and use your medications properly to control your infection. HIV can be passed to your baby if the virus is not controlled during pregnancy. Your name may be listed on a registry to track any effects of antiviral medicine on the baby.

If you are pregnant, do not take didanosine together with stavudine. This combination can be very dangerous during pregnancy.

Women with HIV or AIDS should not breast feed a baby. Even if your baby is born without HIV, the virus may be passed to the baby in your breast milk.

Take the medicine as soon as you can, but skip the missed dose if it is almost time for your next dose. Do not take two doses at one time.

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.

Keep didanosine capsules in the container they came in, tightly closed, and out of reach of children. Store them at room temperature and away from excess heat and moisture (not in the bathroom). Keep didanosine oral solution in the refrigerator, closed tightly, and dispose of any unused medication after 30 days.

It is important to keep all medication out of sight and reach of children as many containers (such as weekly pill minders and those for eye drops, creams, patches, and inhalers) are not child-resistant and young children can open them easily. To protect young children from poisoning, always lock safety caps and immediately place the medication in a safe location – one that is up and away and out of their sight and reach. http://www.upandaway.org

Unneeded medications should be disposed of in special ways to ensure that pets, children, and other people cannot consume them. However, you should not flush this medication down the toilet. Instead, the best way to dispose of your medication is through a medicine take-back program. Talk to your pharmacist or contact your local garbage/recycling department to learn about take-back programs in your community. See the FDA's Safe Disposal of Medicines website (http://goo.gl/c4Rm4p) for more information if you do not have access to a take-back program.

Unless your doctor tells you otherwise, continue your normal diet.

Do not drink alcohol. It may increase your risk of liver damage or pancreatitis.

Avoid using antacids without your doctor's advice while taking didanosine. Use only the specific type of antacid your doctor recommends.

Using didanosine will not prevent your disease from spreading. Do not have unprotected sex or share razors or toothbrushes. Talk with your doctor about safe ways to prevent HIV transmission during sex. Sharing drug or medicine needles is never safe, even for a healthy person.

Get emergency medical help if you have signs of an allergic reaction: hives; difficult breathing; swelling of your face, lips, tongue, or throat.

Mild symptoms of lactic acidosis may worsen over time, and this condition can be fatal. Get emergency medical help if you have: unusual muscle pain, trouble breathing, stomach pain, vomiting, irregular heart rate, dizziness, feeling cold, or feeling very weak or tired.

Didanosine may cause serious side effects. Call your doctor at once if you have:

• numbness, tingling, or pain in your hands or feet;

• bloody or tarry stools, coughing up blood or vomit that looks like coffee grounds;

• vision changes; or

• signs of liver or pancreas problems--loss of appetite, upper stomach pain (that may spread to your back), nausea or vomiting, fast heart rate, dark urine, jaundice (yellowing of the skin or eyes).

Didanosine affects your immune system, which may cause certain side effects (even weeks or months after you've taken didanosine). Tell your doctor if you have:

• signs of a new infection--fever, night sweats, swollen glands, cold sores, cough, wheezing, diarrhea, weight loss;

• trouble speaking or swallowing, problems with balance or eye movement, weakness or prickly feeling; or

• swelling in your neck or throat (enlarged thyroid), menstrual changes, impotence.

Common side effects of didanosine may include:

• nausea, vomiting, diarrhea, stomach pain;

• rash;

• headache; or

• changes in the shape or location of body fat (especially in your arms, legs, face, neck, breasts, and waist).

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

Certain HIV medications or antibiotics should not be taken at the same time as didanosine. These other medicines can affect the levels of didanosine in your bloodstream:

• Ciprofloxacin should be taken at least 2 hours before or 6 hours after you take didanosine.

• Delavirdine or indinavir should be taken at least 1 hour before you take didanosine.

• Nelfinavir should be taken at least 1 hour after you take didanosine.

• Itraconazole or ketoconazole should be taken at least 2 hours before you take didanosine.

Many drugs can affect didanosine, and some drugs should not be used at the same time. Tell your doctor about all your current medicines and any medicine you start or stop using. This includes prescription and over-the-counter medicines, vitamins, and herbal products. Not all possible interactions are listed here.

Do not let anyone else take your medication. Ask your pharmacist any questions you have about refilling your prescription.

Keep a supply of didanosine on hand. Do not wait until you run out of medication to refill your prescription.

It is important for you to keep a written list of all of the prescription and nonprescription (over-the-counter) medicines you are taking, as well as any products such as vitamins, minerals, or other dietary supplements. You should bring this list with you each time you visit a doctor or if you are admitted to a hospital. It is also important information to carry with you in case of emergencies.