Didanosine (Oral)

Didanosine is used together with other medicines to treat 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 stop HIV from multiplying and seems to slow down the damage to the immune system. This may help delay the onset of issues usually associated with AIDS or HIV disease. Didanosine will not prevent you from passing HIV to other people. Individuals taking this medicine may still experience problems typically related to AIDS or HIV disease.

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

The buffered tablets that can 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.

It is very important for your doctor to check your or your child's progress at regular visits to ensure 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.

In deciding to use a medicine, you and your doctor need to think about the risks of taking it compared to the benefits it offers. Here are some important considerations for this medicine:

Allergies

Tell your doctor if you have ever had any unusual or allergic reactions to this medicine or any other medicines. Also inform your healthcare professional about any other allergies you have, such as to foods, dyes, preservatives, or animals. If you are using non-prescription products, read the label or package ingredients carefully.

Pediatric

Studies so far have not shown any specific problems in children aged 2 weeks and older that would limit the usefulness of didanosine.

Geriatric

Studies have not shown any specific problems in elderly patients that would limit the usefulness of didanosine. However, older patients may be more likely to have kidney issues related to aging, which could require caution and a dose adjustment for those taking didanosine.

Breast Feeding

There are no adequate studies in women to determine the risk to infants when using this medicine during breastfeeding. Consider the potential benefits and risks before taking this medicine while breastfeeding.

Interactions with Medicines

Some medicines should not be used together at all, while others may be used together even with possible interactions. If you are taking this medicine, it is very important for your healthcare professional to know if you are also taking any of the medicines listed below. The following interactions are significant and may not include all possible interactions.

Using this medicine with any of the following medicines is not recommended. Your doctor may decide not to prescribe this medication or may adjust your other medications.

• Allopurinol
• Oxypurinol
• Ribavirin
• Stavudine

Using this medicine with any of the following medicines is usually not recommended, but may be necessary in some cases. If both medicines are prescribed together, your doctor may adjust the dose or the frequency of one or both medications.

• Atazanavir
• Cabotegravir
• Darunavir
• Hydroxyurea
• Orlistat
• Tacrolimus
• Tenofovir Disoproxil Fumarate
• Zalcitabine

Using this medicine with any of the following medicines may increase the risk of certain side effects, but using both may be the best treatment for you. If both medicines are prescribed together, your doctor may change the dose or frequency for one or both.

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

Interactions with Food/Tobacco/Alcohol

Some medicines should not be taken around the time of eating food or certain types of food due to possible interactions. Using alcohol or tobacco with certain medicines may also lead to interactions. The following interactions are significant and may not include all possible interactions.

Other Medical Problems

Other medical issues may affect how this medicine works. Be sure to tell your doctor if you have any other medical conditions, especially:

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

• Kidney disease—Use with caution. The effects may be stronger due to slower removal of the medicine from the body.

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

Along with its needed effects, a medicine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor immediately if any of the following side effects occur:

Less common

• Nausea
• stomach pain
• tingling, burning, numbness, and pain in the hands or feet
• vomiting

Rare

• Chills
• fever
• itching, skin rash
• seizures
• sore throat
• swelling of the feet or lower legs
• unusual bleeding and bruising
• unusual tiredness and weakness
• yellow skin and eyes

Incidence not known

• Anxiety
• black, tarry stools
• bleeding gums
• blindness
• bloating
• blood in the urine or stools
• blue-yellow color blindness
• blurred vision
• change in the color of the eye
• chest pain
• clay colored stools
• cold sweats
• confusion
• constipation
• cool, pale skin
• cough
• dark urine
• decreased appetite
• decreased vision
• depression
• diarrhea
• difficulty with moving
• difficulty with swallowing
• dizziness
• dry eyes or mouth
• eye pain
• fast heartbeat
• fast, shallow breathing
• flushed, dry skin
• fruit-like breath odor
• general feeling of discomfort
• headache
• hives
• increased hunger
• increased thirst
• increased urination
• indigestion
• joint pain
• light-colored stools
• loss of appetite
• loss of consciousness
• muscle aching, cramping, or pain
• nightmares
• painful or difficult urination
• pains in the stomach, side, or abdomen, possibly radiating to the back
• pinpoint red spots on the skin
• puffiness or swelling of the eyelids or around the eyes, face, lips, or tongue
• right upper abdominal or stomach pain and fullness
• shakiness
• sleepiness
• slurred speech
• sores, ulcers, or white spots on the lips or in the mouth
• stomach ache or discomfort
• sweating
• swollen glands or joints
• tightness in the chest
• troubled breathing with exertion
• unexplained weight loss
• unsteadiness or awkwardness
• weakness in the arms, hands, legs, or feet

Some side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

More common

• Difficulty with sleeping
• irritability
• restlessness

Incidence not known

• Belching
• excess air or gas in the stomach or bowels
• feeling of fullness
• hair loss or thinning of the hair
• heartburn
• indigestion
• lack or loss of strength
• passing gas

Other side effects not listed may also occur in some patients. If you notice any other effects, check with your healthcare professional.

Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.

In the U.S.

• Videx
• Videx EC
• Videx Pediatric

Available Dosage Forms:

• Capsule, Delayed Release

Therapeutic Class: Antiretroviral Agent

Pharmacologic Class: Nucleoside Reverse Transcriptase Inhibitor

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.

Dosing

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.

Missed Dose

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.

Storage

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.