- What is didanosine, and how does it work (mechanism of action)?
- What are the uses for didanosine?
- What are the side effects of didanosine?
- What is the dosage for didanosine?
- Which drugs or supplements interact with didanosine?
- Is didanosine safe to take if I'm pregnant or breastfeeding?
- What else should I know about didanosine?
What is didanosine, and how does it work (mechanism of action)?
Didanosine is an oral medication that is used for the treatment of infections with the human immunodeficiency virus (HIV). It is in a class of drugs called reverse transcriptase inhibitors which also includes zalcitabine (Hivid), zidovudine (Retrovir), stavudine (Zerit), and lamivudine (Epivir). During infection with HIV, the HIV virus multiplies within the body's cells. The newly-formed viruses then are released from the cells and spread throughout the body where they infect other cells. In this manner, the infection spreads to new, uninfected cells that the body is continually producing, and HIV infection is perpetuated. When producing new viruses, the HIV virus must manufacture new DNA for each virus. Reverse transcriptase is the enzyme that the virus uses to form this new DNA. Specifically, didanosine is converted within the body to its active form (dideoxyadenosine triphosphate). This active form is similar to a chemical, deoxyadenosine triphosphate, that is required by the HIV virus to make new DNA. The reverse transcriptase uses dideoxyadenosine triphosphate instead of deoxyadenosine triphosphate for making DNA, and the dideoxyadenosine triphosphate that interferes with the reverse transcriptase. Didanosine does not kill existing HIV virus and it is not a cure for HIV. The FDA approved didanosine in October 1991.
What brand names are available for didanosine?
Videx, Videx EC
Is didanosine available as a generic drug?
GENERIC AVAILABLE: Yes
Do I need a prescription for didanosine?
Yes
What are the side effects of didanosine?
The most severe side effects of didanosine are:
- inflammation of the pancreas (pancreatitis),
- liver failure, and
- nerve damage in the arms and legs (peripheral neuropathy).
Symptoms of peripheral neuropathy are tingling, numbness and pain in the feet or hands.
Other important side effects include:
What is the dosage for didanosine?
Adults weighing 60 kg or more should receive 400 mg once daily of the capsules or 200 mg twice daily of the powder. Adults weighing less than 60 kg require 250 mg once daily of the capsules and 125 mg twice daily of the powder.
Didanosine should be administered on an empty stomach because food reduces the absorption of didanosine by as much as 46%.

SLIDESHOW
A Timeline of the HIV/AIDS Pandemic See SlideshowWhich drugs or supplements interact with didanosine?
Didanosine powder contains an antacid which reduces the absorption of tetracycline (for example, Vibramycin, Minocin), ketoconazole (Nizoral), fluoroquinolone antibiotics (for example, ciprofloxacin [Cipro], Floxin), and other drugs that need stomach acid for absorption. Therefore, these drugs should be administered at least two hours before or after administration of didanosine solution.
Allopurinol (Zyloprim), tenofovir (Viread), and ganciclovir (Cytovene) increase blood levels of didanosine by reducing its elimination.
Is didanosine safe to take if I'm pregnant or breastfeeding?
Although it is not known whether didanosine is excreted in breast milk, HIV-infected mothers should not breast feed because of the potential risk of transmitting HIV to an infant that is not infected.
What else should I know about didanosine?
What preparations of didanosine are available?
Capsules (Extended Release): 125, 200, 250, and 400 mg. Solution: 10 mg/ml
How should I keep didanosine stored?
Capsules and unmixed powder should be stored at room temperature, 15 C to 30 C (59 F to 86 F). The powder may be stored in the refrigerator at 2 C to 8 C (36 F to 46 F for up to 30 days after it is mixed with water.
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Summary
Didanosine (Videx, Videx EC) is a drug prescribed for the treatment of the human immunodeficiency virus (HIV) in adults and children. Review side effects, dosage, drug interactions, pregnancy safety, and warnings and precautions information prior to taking this medication.
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Related Disease Conditions
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Human Immunodeficiency Virus (HIV)
HIV (human immunodeficiency virus) infection left untreated causes AIDS (acquired immunodeficiency syndrome). The human immunodeficiency virus (HIV) is a type of virus called a retrovirus, which can infect humans when it comes in contact with tissues that line the vagina, anal area, mouth, or eyes, or through a break in the skin. HIV infection is generally a slowly progressive disease in which the virus is present throughout the body at all stages of the disease. Three stages of HIV infection have been described. The initial stage of infection (primary infection), which occurs within weeks of acquiring the virus, often is characterized by the flu- or mono-like illness that generally resolves within weeks. The stage of chronic asymptomatic infection (meaning a long duration of infection without symptoms) lasts an average of eight to 10 years without treatment. The stage of symptomatic infection, in which the body's immune (or defense) system has been suppressed and complications have developed, is called the acquired immunodeficiency syndrome (AIDS). The symptoms are caused by the complications of AIDS, which include one or more unusual infections or cancers, severe loss of weight, and intellectual deterioration (called dementia). When HIV grows (that is, by reproducing itself), it acquires the ability to change (mutate) its own structure. These mutations enable the virus to become resistant to previously effective drug therapy. The goals of drug therapy are to prevent damage to the immune system by the HIV virus and to halt or delay the progress of the infection to symptomatic disease. Therapy for HIV includes combinations of drugs that decrease the growth of the virus to such an extent that the treatment prevents or markedly delays the development of viral resistance to the drugs. The best combination of drugs for HIV are those that effectively suppress viral replication in the blood and also are well tolerated and simple to take so that people can take the medications consistently without missing doses.
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AIDS (Acquired Immunodeficiency Syndrome)
AIDS is the advanced stage of HIV infection. Symptoms and signs of AIDS include pneumonia due to Pneumocystis jiroveci, tuberculosis, toxoplasmosis, seizures, weakness, meningitis, yeast infection of the esophagus, and Kaposi's sarcoma. Anti-retroviral therapy (HAART) is used in the treatment of AIDS.
Treatment & Diagnosis
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- Pharmacy Visit, How To Get The Most Out of Your Visit
- Indications for Drugs: Approved vs. Non-approved
- Drugs: The Most Common Medication Errors
- Medication Disposal
- Dangers of Mixing Medications
- Drugs: Buying Prescription Drugs Online Safely
- Generic Drugs, Are They as Good as Brand-Names?
Medications & Supplements
- Drugs: Questions to Ask Your Doctor or Pharmacist about Your Drugs
- Drug Interactions
- abacavir, Ziagen
- Retrovir (zidovudine, ZDV, formerly called AZT)
- lamivudine (3tc) (Epivir; Epivir HBV)
- efavirenz (Sustiva)
- zalcitabine
- delavirdine (Rescriptor)
- nevirapine (Viramune, Viramune XR)
- Combivir (lamivudine and zidovudine)
- abacavir, lamivudine, zidovudine (Trizivir)
- Side Effects of Videx (didanosine)
- stavudine (Zerit)
Prevention & Wellness
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Report Problems to the Food and Drug Administration
You are encouraged to report negative side effects of prescription drugs to the FDA. Visit the FDA MedWatch website or call 1-800-FDA-1088.