What is Didanosine?

Warning: Pancreatitis, Lactic Acidosis and Hepatomegaly with SteatosisFatal and nonfatal pancreatitis has occurred during therapy with didanosine used alone or in combination regimens in both treatment-naive and treatment-experienced patients, regardless of degree of immunosuppression. Didanosine should be suspended in patients with suspected pancreatitis and discontinued in patients with confirmed pancreatitis .Lactic acidosis and severe hepatomegaly with steatosis, including fatal cases, have been reported with the use of nucleoside analogues alone or in combination, including didanosine and other antiretrovirals. Fatal lactic acidosis has been reported in pregnant women who received the combination of didanosine and stavudine with other antiretroviral agents .Coadministration of didanosine and stavudine is contraindicated because of increased risk of serious and/or life-threatening events. Suspend treatment if clinical or laboratory findings suggestive of lactic acidosis or pronounced hepatotoxicity occurs

Didanosine is used in combination with other medicines for the treatment of human immunodeficiency virus (HIV) infection. HIV is the virus that causes acquired immune deficiency syndrome (AIDS).

Didanosine will not cure or prevent HIV infection or AIDS. It helps keep HIV from reproducing and appears to slow down the destruction of the immune system. This may help delay the development of problems usually related to AIDS or HIV disease. Didanosine will not keep you from spreading HIV to other people. People who receive this medicine may continue to have the problems usually related to AIDS or HIV disease.

This medicine is available only with your doctor's prescription.

The buffered tablets that are to be chewed, crushed or mixed with water are no longer available in the United States. This product was voluntarily discontinued, and it was not due to safety concerns. Didanosine delayed-release capsules (Videx® EC) and pediatric powder for oral solution are still available.

Take this medicine exactly as directed by your doctor. Do not take more of it, do not take it more often, and do not take it for a longer time than your doctor ordered. Also, do not stop taking this medicine without checking first with your doctor.

This medicine comes with a Medication Guide. Read and follow these instructions carefully. Ask your doctor if you have any questions.

Keep taking didanosine for the full time of treatment, even if you begin to feel better. Only take medicine that your doctor has prescribed specifically for you. Do not share your medicine with other people.

This medicine works best when there is a constant amount in the blood. To help keep the amount constant, do not miss any doses. If you need help in planning the best times to take your medicine, check with your doctor.

Didanosine should be taken on an empty stomach since food may keep it from working properly. Didanosine oral liquid should be taken at least 30 minutes before or 2 hours after you eat.

Swallow the delayed-release capsule whole. Do not break, crush, chew, or open it.

Shake the oral liquid before use. Measure each dose with a specially marked measuring spoon or measuring cup. The average household teaspoon may not hold the right amount of liquid.

The dose of this medicine will be different for different patients. Follow your doctor's orders or the directions on the label. The following information includes only the average doses of this medicine. If your dose is different, do not change it unless your doctor tells you to do so.

The amount of medicine that you take depends on the strength of the medicine. Also, the number of doses you take each day, the time allowed between doses, and the length of time you take the medicine depend on the medical problem for which you are using the medicine.

• For HIV infection:
  • For oral dosage form (delayed-release capsules):
    • Adults and children who can swallow capsules—Dose is based on body weight and must be determined by your doctor.
      • For patients weighing 60 kilograms (kg) or more—400 milligrams (mg) once a day.
      • For patients weighing 25 kg to less than 60 kg—250 mg once a day.
      • For patients weighing 20 kg to less than 25 kg—200 mg once a day.
    • Children weighing less than 20 kg—The oral capsules are not given to small children.
  • For oral dosage form (solution):
    • Adults weighing 60 kilograms (kg) or more—Dose is based on body weight and must be determined by your doctor. The usual dose is 200 milligrams (mg) 2 times a day or 400 mg once a day.
    • Adults weighing less than 60 kg—Dose is based on body weight and must be determined by your doctor. The usual dose is 125 mg 2 times a day or 250 mg once a day.
    • Children older than 8 months of age—Dose is based on body size and must be determined by your doctor. The usual dose is 120 milligrams per square meter (mg/m(2)) 2 times a day.
    • Infants 2 weeks to 8 months old—Dose is based on body size and must be determined by your doctor. The usual dose is 100 mg/m(2) 2 times a day.
    • Infants younger than 2 weeks old—Use and dose must be determined by your doctor.

If you miss a dose of this medicine, take it as soon as possible. However, if it is almost time for your next dose, skip the missed dose and go back to your regular dosing schedule. Do not double doses.

Keep out of the reach of children.

Do not keep outdated medicine or medicine no longer needed.

Ask your healthcare professional how you should dispose of any medicine you do not use.

Store the delayed-release capsules in a closed container at room temperature, away from heat, moisture, and direct light. Keep from freezing.

Store the oral liquid in the refrigerator. Throw away any unused medicine after 30 days.

In deciding to use a medicine, the risks of taking the medicine must be weighed against the good it will do. This is a decision you and your doctor will make. For this medicine, the following should be considered:

Tell your doctor if you have ever had any unusual or allergic reaction to this medicine or any other medicines. Also tell your health care professional if you have any other types of allergies, such as to foods, dyes, preservatives, or animals. For non-prescription products, read the label or package ingredients carefully.

Appropriate studies performed to date have not demonstrated pediatric-specific problems that would limit the usefulness of didanosine in children 2 weeks of age and older.

Appropriate studies performed to date have not demonstrated geriatric-specific problems that would limit the usefulness of didanosine in the elderly. However, elderly patients are more likely to have age-related kidney problems, which may require caution and an adjustment in the dose for patients receiving didanosine.

There are no adequate studies in women for determining infant risk when using this medication during breastfeeding. Weigh the potential benefits against the potential risks before taking this medication while breastfeeding.

Although certain medicines should not be used together at all, in other cases two different medicines may be used together even if an interaction might occur. In these cases, your doctor may want to change the dose, or other precautions may be necessary. When you are taking this medicine, it is especially important that your healthcare professional know if you are taking any of the medicines listed below. The following interactions have been selected on the basis of their potential significance and are not necessarily all-inclusive.

Using this medicine with any of the following medicines is not recommended. Your doctor may decide not to treat you with this medication or change some of the other medicines you take.

• Allopurinol
• Oxypurinol
• Ribavirin
• Stavudine

Using this medicine with any of the following medicines is usually not recommended, but may be required in some cases. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.

• Darunavir
• Hydroxyurea
• Orlistat
• Tenofovir Disoproxil Fumarate
• Zalcitabine

Using this medicine with any of the following medicines may cause an increased risk of certain side effects, but using both drugs may be the best treatment for you. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.

• Atazanavir
• Atevirdine
• Ciprofloxacin
• Delavirdine
• Enoxacin
• Ganciclovir
• Indinavir
• Itraconazole
• Ketoconazole
• Lomefloxacin
• Methadone
• Metoclopramide
• Moxifloxacin
• Nelfinavir
• Norfloxacin
• Ofloxacin
• Ranitidine
• Rifabutin
• Ritonavir
• Sulfamethoxazole
• Trimethoprim
• Trovafloxacin Mesylate
• Valganciclovir

Certain medicines should not be used at or around the time of eating food or eating certain types of food since interactions may occur. Using alcohol or tobacco with certain medicines may also cause interactions to occur. The following interactions have been selected on the basis of their potential significance and are not necessarily all-inclusive.

The presence of other medical problems may affect the use of this medicine. Make sure you tell your doctor if you have any other medical problems, especially:

• Alcohol use, active or history of or
• Liver disease (including hepatitis) or
• Obesity (overweight) or
• Pancreatitis (inflammation of the pancreas), history of or
• Peripheral neuropathy (nerve disorder), history of—Use with caution. May cause side effects to become worse.

• Kidney disease—Use with caution. The effects may be increased because of slower removal of the medicine from the body.

• Portal hypertension (high blood pressure in the portal vein of the liver)—Use with caution. May make this condition worse.

It is very important that your doctor check your or your child's progress at regular visits to make sure that this medicine is working properly. Blood tests may be needed to check for unwanted effects.

Do not use didanosine if you or your child are also using allopurinol (Zyloprim®), ribavirin (Copegus®, Rebetol®), or stavudine (Zerit®). Using these medicines together may cause serious side effects.

This medicine may cause a life-threatening condition called pancreatitis. Check with your doctor right away if you or your child have more than one of these symptoms: bloating, chills, constipation, darkened urine, a fast heartbeat, fever, indigestion, loss of appetite, nausea, pains in the stomach, side, or abdomen, possibly radiating to the back, vomiting, or yellow eyes or skin.

Two rare but serious reactions to this medicine are lactic acidosis (too much acid in the blood) and liver toxicity, which includes an enlarged liver. These are more common if you are female, very overweight (obese), or have been taking anti-HIV medicines for a long time. Call your doctor right away if you or your child have more than one of these symptoms: abdominal or stomach discomfort or cramping, dark urine, decreased appetite, diarrhea, a general feeling of discomfort, light-colored stools, muscle cramping or pain, nausea, unusual tiredness or weakness, trouble breathing, vomiting, or yellow eyes or skin.

Check with your doctor right away if you or your child have abdominal or stomach pain, black, tarry stools, bleeding gums, blood in the urine or stools, pinpoint red spots on the skin, or unusual bleeding or bruising. These may be symptoms of a condition called non-cirrhotic portal hypertension.

Tell your doctor right away if you or your child start having numbness, tingling, or burning pain in your hands, arms, legs, or feet. These may be symptoms of a condition called peripheral neuropathy.

Your immune system may get stronger when you start taking HIV medicines. Sometimes the immune system will start to fight infections that were hidden in your body, such as pneumonia or tuberculosis, or may result in a flare-up of a hidden autoimmune disorder such as Graves' disease, polymyositis, or Guillain-Barré syndrome. Tell your doctor right away if you notice any changes in your health.

This medicine may cause you or your child to lose fat from your legs, arms, or face. Talk to your doctor if you have any concerns.

Check with your doctor right away if you or your child start to see unusual colors or have blurred vision. Your doctor may want you to have your eyes checked regularly by an eye doctor (ophthalmologist).

Do not drink alcohol while you are using this medicine.

This medicine will not keep you from giving HIV to your partner during sex. Make sure you understand this and practice safe sex, even if your partner also has HIV, by using a latex condom or other barrier method. This medicine will also not keep you from giving HIV to other people if they are exposed to your blood. Do not re-use or share needles with anyone.

Do not take other medicines unless they have been discussed with your doctor. This includes prescription or nonprescription (over-the-counter [OTC]) medicines and herbal or vitamin supplements.