Didanosine

Why is this medicine prescribed?

Didanosine is used along with other medications to treat human immunodeficiency virus (HIV) infection. Didanosine is in a class of medications called nucleoside reverse transcriptase inhibitors (NRTIs). It works by decreasing the amount of HIV in the blood. Although didanosine does not cure HIV, it may decrease your chance of developing acquired immunodeficiency syndrome (AIDS) and HIV-related illnesses such as serious infections or cancer. Taking these medications along with practicing safer sex and making other lifestyle changes may decrease the risk of transmitting (spreading) the HIV virus to other people.

Are there other uses for this medicine?

Didanosine is also sometimes used with other medications to help prevent infection in healthcare workers or other people who were accidentally exposed to HIV. Talk to your doctor about the possible risks of using this medication for your condition.

This medication may be prescribed for other uses; ask your doctor or pharmacist for more information.

How should this medicine be used?

Didanosine comes as extended-release (long-acting) capsules and as an oral solution (liquid) to take by mouth. The oral solution is usually taken once or twice a day 30 minutes before or 2 hours after eating. The extended-release capsules are usually taken once a day on an empty stomach. Take didanosine around the same time(s) every day. Follow the directions on your prescription label carefully, and ask your doctor or pharmacist to explain any part you do not understand. Take didanosine exactly as directed. Do not take more or less of it, or take it more often than prescribed by your doctor.

If you are using the extended-release capsules, swallow them whole; do not split, chew, crush, break, or dissolve them. Tell your doctor if you are unable to swallow the extended-release capsules whole.

If you are taking the oral solution, you should shake it well before each use to mix the medication evenly. Use a dose-measuring spoon or cup to measure the correct amount of liquid for each dose, not a regular household spoon.

Didanosine controls HIV infection but does not cure it. Continue to take didanosine even if you feel well. Do not stop taking didanosine without talking to your doctor. If you miss doses or stop taking didanosine, your condition may become more difficult to treat.

What special precautions should I follow?

Before taking didanosine,

• tell your doctor and pharmacist if you are allergic to didanosine, any other medications, or any of the ingredients in didanosine capsules or oral solution. Ask your pharmacist or check the Medication Guide for a list of the ingredients.
• tell your doctor if you are taking allopurinol (Aloprim, Lopurin, Zyloprim), or ribavirin (Copegus, Rebetol, Virazole). Your doctor will probably tell you not to take didanosine if you are taking one or both of these medications.
• tell your doctor and pharmacist what other prescription and nonprescription medications, vitamins, nutritional supplements, and herbal products you are taking or plan to take. Be sure to mention any of the medications listed in the IMPORTANT WARNING section and the following: antacids containing aluminum or magnesium (Maalox, Mylanta, others): antifungals such as itraconazole (Sporanox) and ketoconazole; atazanvir (Reyataz); antibiotics such as ciprofloxacin (Cipro), gatifloxacin (Tequin), moxifloxacin (Avelox), ofloxacin (Floxin), pentamidine (Nebupent, Pentam), sulfamethoxazole and trimethoprim (Bactrim, Septra), and tetracycline (Sumycin); cabazitaxel (Jevtana); dapsone (Aczone); delavirdine (Rescriptor); docetaxel (Taxotere); ganciclovir (Cytovene); hydroxyurea (Droxia, Hydrea); indinavir (Crixivan); methadone (Dolophine, Methadose); nelfinavir (Viracept); paclitaxel (Abraxane, Taxol); pentamidine (Nebupent, Pentam); ranitidine (Zantac); ritonavir (Norvir); sulfamethoxazole and trimethoprim (Bactrim, Septra). tenofovir (Viread); tipranavir (Aptivus); valganciclovir (Valcyte); or vincristine (Marqibo). Your doctor may need to change the doses of your medications, change when you are taking your medications, or monitor you carefully for side effects. Many other medications may also interact with didanosine, so be sure to tell your doctor about all the medications you are taking, even those that do not appear on this list.
• tell your doctor if you have or have ever had peripheral neuropathy (numbness, tingling, burning, or pain sensation in your hands or feet, or decreased ability to feel temperature or touch in your hands or feet) or kidney disease.
• tell your doctor if you are pregnant, plan to become pregnant, or are breastfeeding. If you become pregnant while taking didanosine, call your doctor. You should not breastfeed if you are infected with HIV or if you are taking didanosine.
• you should know that didanosine may cause side effects that must be treated right away before they become serious. Children who are taking didanosine may not be able to tell you about the side effects they are feeling. If you are giving didanosine to a child, ask the child's doctor how you can tell if the child is having these serious side effects.
• you should know that you may have a loss of body fat from your face, legs, arms, and buttocks. Talk to your doctor if you notice this change.
• you should know that while you are taking medications to treat HIV infection, your immune system may get stronger and begin to fight other infections that were already in your body. This may cause you to develop symptoms of those infections. If you have new or worsening symptoms after starting treatment with didanosine, be sure to tell your doctor.

What special dietary instructions should I follow?

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

What should I do if I forget to take a dose?

Take the missed dose as soon as you remember it. However, if it is almost time for the next dose, skip the missed dose and continue your regular dosing schedule. Do not take a double dose to make up for a missed one.

What should I do in case of overdose?

In case of overdose, call the poison control helpline at 1-800-222-1222. Information is also available online at https://www.poisonhelp.org/help . If the victim has collapsed, had a seizure, has trouble breathing, or can't be awakened, immediately call emergency services at 911.

Symptoms of overdose may include the following:

• diarrhea
• numbness, tingling, burning, or pain in hands or feet
• nausea
• vomiting
• loss of appetite
• stomach pain
• swelling of the stomach
• muscle or joint pain
• extreme tiredness
• weakness
• dizziness
• lightheadedness
• fast, slow or irregular heartbeat
• deep or rapid breathing
• shortness of breath
• dark yellow or brown urine
• unusual bleeding or bruising
• vomiting a substance that is bloody or looks like coffee grounds
• dark stools
• yellowing of the skin or eyes
• feeling cold
• fever
• flu-like symptoms

What side effects can this medicine cause?

Didanosine may cause side effects. Tell your doctor if this symptom is severe or does not go away:

• headache

Some side effects can be serious. If you experience any of the following symptoms or those mentioned in the IMPORTANT WARNING section, call your doctor immediately:

• hives
• rash
• itching
• difficulty breathing or swallowing
• numbness, tingling, burning, or pain in hands or feet
• vision changes
• difficulty in seeing colors clearly

Didanosine may cause other side effects. Call your doctor if you have any unusual problems while taking this medication.

If you experience a serious side effect, you or your doctor may send a report to the Food and Drug Administration's (FDA) MedWatch Adverse Event Reporting program online ( http://www.fda.gov/Safety/MedWatch ) or by phone (1-800-332-1088).

What should I know about storage and disposal of this medication?

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.

What other information should I know?

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.