Didanosine (patient information)

# IMPORTANT WARNING
Didanosine, when used alone or in combination with other medications, can cause serious damage to the liver and pancreas and a condition called lactic acidosis. Tell your doctor if you drink or have ever drunk large amounts of alcohol; if you use or have used street drugs; or if you have or have ever had Crohn's disease, cystic fibrosis, diabetes, high cholesterol, or liver or pancreas disease. Tell your doctor and pharmacist if you are taking stavudine (Zerit), especially if you are pregnant. Tell your doctor and pharmacist if you are taking or have taken any of the following medications: acetaminophen (Tylenol, others); allopurinol (Zyloprim); amiodarone (Cordarone, Pacerone); azathioprine (Imuran); cholesterol-lowering medications (statins); dantrolene (Dantrium); furosemide (Lasix); hormone replacement therapy; iron products; isoniazid (INH, Nydrazid); ketoconazole (Nizoral); medications to treat HIV or AIDS; 6-mercaptopurine (Purinethol); methotrexate (Rheumatrex); methyldopa (Aldoril); niacin (nicotinic acid); oral contraceptives (birth control pills); oral steroids such as dexamethasone (Decadron, Dexone), methylprednisolone (Medrol), and prednisone (Deltasone); pentamidine (Nebupent, Pentam); piroxicam (Feldene); pyrazinamide (Rifater); ribavirin (Rebetron); rifampin (Rifadin, Rimactane); salicylate pain relievers such as aspirin, choline magnesium trisalicylate (Trisalate), choline salicylate (Arthropan), diflunisal (Dolobid), magnesium salicylate (Doan's, others), and salsalate (Argesic, Disalcid, Salgesic); sulfonamide antibiotics such as sulfadiazine, sulfamethizole (Urobiotic), sulfasalazine (Azulfidine), and sulfisoxazole (Eryzole, Gantrisin, Pediazole); sulindac (Clinoril); valproic acid (Depakene, Depakote); or products containing kava. If you experience any of the following symptoms, call your doctor immediately: upset stomach, vomiting, loss of appetite, stomach pain or swelling, severe back pain, extreme tiredness, weakness, dizziness, light-headedness, fast heart beat, sudden development of a slow or irregular heartbeat, deep or rapid breathing, shortness of breath, dark yellow or brown urine, unusual bleeding or bruising, yellowing of the skin or eyes, feeling cold, fever, or flu-like symptoms.
Ask your doctor about the safe use of alcohol while you are taking didanosine. Drinking alcohol can increase the risk that you will develop serious side effects of didanosine.
Keep all appointments with your doctor and the laboratory. Your doctor will order certain lab tests to check your body's response to didanosine. Talk to your doctor about the risks of taking didanosine.

# Why this medication is prescribed
Didanosine is used with other medications to treat human immunodeficiency virus (HIV) infection in patients with or without acquired immunodeficiency syndrome (AIDS). Didanosine is in a class of medications called nucleoside reverse transcriptase inhibitors (NRTIs). Didanosine works by slowing the spread of HIV in the body. Didanosine does not cure HIV infection and may not prevent you from developing HIV-related illnesses. Didanosine does not prevent you from spreading HIV to other people.

# How this medication should be used
Didanosine comes as extended-release (long-acting) capsules, tablets that can be chewed or mixed with water, a powder to be mixed with water, and a solution (liquid). All are taken by mouth. Didanosine is usually taken once or twice a day on an empty stomach, 30 minutes before or 2 hours after eating. To help you remember to take didanosine, take it 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, or open them.
If you are using the tablets, do not swallow them whole. Chew the tablets well or mix them in at least 1 ounce of water and stir well to dissolve the tablets before swallowing. You may add one ounce (2 tablespoonfuls) of clear apple juice to the mixture for flavor, if needed. Do not use any other kind of juice. Drink all of the liquid right away.
If you are using the powder, you must mix it with water immediately before you take it. Open the packet and pour the powder into a glass with four ounces (1/2 cup) of water. Stir the mixture for 2 or 3 minutes until the powder is completely dissolved. Drink all of the liquid right away. Do not mix the powder with fruit juice or any other liquid.
If you are using the 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 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.

# Other uses for this medicine
Didanosine is also used with another medication to help prevent infection in health care workers or other people who were accidentally exposed to HIV. Talk to your doctor about the possible risks of using this drug for your condition.
This medication may be prescribed for other uses; ask your doctor or pharmacist for more information.

# Special precautions
Before taking didanosine:
- tell your doctor and pharmacist if you are allergic to didanosine, aspartame (Nutrasweet), antacids, or any other medications.
- tell your doctor and pharmacist what other prescription and nonprescription medications, vitamins, and nutritional supplements you are taking. Be sure to mention any of the medications listed in the IMPORTANT WARNING section and the following: antacids; cancer chemotherapy medications; ganciclovir (Cytovene); methadone (Dolophine, Methadose); tenofovir (Viread); or zalcitabine (HIVID). Your doctor may need to change the doses of your medications or monitor you carefully for side effects.
- you should know that some medications must be taken several hours before or after you take didanosine. If you are taking any of the following medications, ask your doctor exactly when you should take them: anticoagulants ('blood thinners') such as warfarin (Coumadin); antifungals such as itraconazole (Sporanx) and ketoconazole (Nizoral); delavirdine (Rescriptor), digoxin (Lanoxin, Lanoxicaps); indinavir (Crixivan); nelfinavir (Viracept); quinolone antibiotics such as cinoxacin (Cinobac), ciprofloxacin (Cipro), enoxacin (Penetrex), gatifloxacin (Tequin), levofloxacin (Levaquin), lomefloxacin (Maxaquin), moxifloxacin (Avelox), nalidixic acid (NegGram), norfloxacin (Noroxin), ofloxacin (Floxin), sparfloxacin (Zagam), and trovafloxacin and alatrofloxacin combination (Trovan); tetracycline antibiotics such as demeclocycline (Declomycin), doxycycline (Doryx, Vibramycin), minocycline (Dynacin, Minocin), and tetracycline (Sumycin); and zinc supplements.
- tell your doctor if you are on a low-salt diet and if you have or have ever had eye disease or problems with your vision, muscle problems, gout, 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), radiation therapy, phenylketonuria (PKU, a disease in which you must avoid certain foods), or heart or kidney disease.
- tell your doctor if you are pregnant, plan to become pregnant, or are breast-feeding. If you become pregnant while taking didanosine, call your doctor. You should not breastfeed if you are infected with HIV or 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 your body fat may increase or move to different areas of your body such as your breasts and upper back.

# Special dietary instructions
Unless your doctor tells you otherwise, continue your normal diet.

# What to do if you forget 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.

# Side effects

## Minor side effects
Didanosine may cause side effects. Tell your doctor if any of these symptoms are severe or do not go away:
- diarrhea
- headache
- muscle pain

## Severe side effects
Some side effects can be serious. The following symptoms are uncommon, but if you experience any of them, or those mentioned in the IMPORTANT WARNING section, call your doctor immediately:
- hives
- skin rash
- itching
- difficulty breathing or swallowing
- numbness, tingling, burning, or pain in hands or feet
- blurred vision
- difficulty in seeing colors clearly
- chills
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  or by phone .

# Storage conditions needed for this medication
Keep didanosine capsules, tablets, and powder in the containers 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). Use mixtures of tablets and apple juice within 1 hour, and mixtures of powder and water within 4 hours. Keep didanosine liquid in the refrigerator, closed tightly, and throw away any unused medication after 30 days. Throw away any medication that is outdated or no longer needed. Talk to your pharmacist about the proper disposal of your medication.

# In case of emergency/overdose
In case of overdose, call your local poison control center at 1-800-222-1222. If the victim has collapsed or is not breathing, call local emergency services at 911.
Symptoms of overdose may include:
- diarrhea
- numbness, tingling, burning, or pain in hands or feet
- upset stomach
- vomiting
- loss of appetite
- stomach pain
- swelling of the stomach
- severe back pain
- extreme tiredness
- weakness
- dizziness
- light-headedness
- fast heart beat
- sudden development of a slow or irregular heartbeat
- deep or rapid breathing
- shortness of breath
- dark yellow or brown urine
- unusual bleeding or bruising
- yellowing of the skin or eyes
- feeling cold
- fever
- flu-like symptoms

# Other information
Do not let anyone else take your medication. Ask your pharmacist any questions you have about refilling your prescription.
If you spill a packet of didanosine powder or didanosine liquid, clean the area of the spill with a wet mop or damp sponge using soap and water. Clean the area slowly so you do not make dust in the air. Try to keep all of the spill in one area. Wash your hands and the clean-up materials well after use.

# Brand names
- Videx
- Videx EC
- Videx Pediatric

# Other names
- ddI
- dideoxyinosine