Generic name: Didanosine

What is Videx?

Videx is an antiviral medication used to treat human immunodeficiency virus (HIV) infection. Videx is also sometimes used in combination with other medications to treat hepatitis B. Videx belongs to a class of drugs called nucleoside reverse transcriptase inhibitors (NRTIs). It works by inhibiting the activity of reverse transcriptase, an enzyme needed for the virus to replicate. Videx does not cure HIV or AIDS, but it may decrease your risk of developing acquired immune deficiency syndrome (AIDS) and HIV-related illnesses such as infections and cancer. Videx is available in generic form.

Health Benefits

Videx is used in the treatment of human immunodeficiency virus (HIV) infection. Videx is also sometimes used in combination with other medications to treat hepatitis B.

Side Effects and Risks

The most common side effects of Videx include headache, diarrhea, nausea, and vomiting. Videx may also cause dizziness. This effect may be increased if you take Videx with alcohol or other medications that can cause drowsiness. You should not drive or operate heavy machinery until you know how Videx affects you. Other serious side effects of Videx include:

• Pancreatitis (inflammation of the pancreas)

• Lactic acidosis (buildup of lactic acid in the blood)

• Peripheral neuropathy (nerve damage)

• Hepatotoxicity (liver damage)

• Anemia (low red blood cell count)

• Skin rash

Talk to your doctor about the potential side effects of Videx before starting treatment.

Dosage

The recommended dose of Videx for adults is 200 mg taken twice daily. For children ages 3 to 18, the recommended dose is weight-based. The usual starting dose is 8 mg/kg (up to a maximum of 200 mg) taken twice daily.

Videx may be taken with or without food. If you experience stomach upset, you may take Videx with food.

Drug Interactions

Videx may interact with other medications. Tell your doctor all prescription and over-the-counter medications and supplements you take. Videx should not be taken with the following medications:

• Adenovirus type 5 vaccine ( live)

Yellow fever vaccine (live)

Rotavirus vaccine, live (RotaTeq, Rotarix)

• Zidovudine (Retrovir)

• Stavudine (Zerit)

• Didanosine (Videx, Videx EC)

• Lamivudine (Epivir, Epivir-HBV)

• Emtricitabine/tenofovir (Atripla, Complera, Truvada)

Tenofovir disoproxil fumarate (Viread)

Emtricitabine/rilpivirine/tenofovir disoproxil fumarate (Complera)

Emtricitabine/efavirenz/tenofovir disoproxil fumarate (Atripla)

• Rilpivirine (Edurant)

Efavirenz (Sustiva, Atripla)

• Acyclovir (Zovirax)

Famciclovir (Famvir)

Valacyclovir (Valtrex)

• Pentamidine (NebuPent, Pentam 300)

Tell your doctor if you are taking any of these medications. Your doctor may need to adjust your dose or monitor you more closely for side effects. Videx may also interact with:

• Birth control pills or patch

• Probenecid (Benemid)

• Blood thinners such as warfarin (Coumadin)

• This list is not complete and other drugs may interact with Videx. Tell your doctor about all medications you use. This includes prescription, over-the-counter, vitamin, and herbal products. Do not start a new medication without telling your doctor.

Mechanism of Action

Videx belongs to a class of drugs called nucleoside reverse transcriptase inhibitors (NRTIs). It works by inhibiting the activity of reverse transcriptase, an enzyme needed for the virus to replicate.

Pharmacokinetics

Videx is rapidly absorbed from the gastrointestinal tract and reaches peak concentrations in 1 to 4 hours. The bioavailability of Videx is approximately 60%. Videx is widely distributed in the body and has a volume of distribution of approximately 140 L. Videx is 96% bound to plasma proteins.

Videx is metabolized by nucleoside phosphorylase to 2′-3′-dideoxyinosine monophosphate (ddI-MP). ddI-MP is further metabolized by adenosine deaminase to 2′,3′-dideoxyinosine (ddI). ddI is eliminated primarily by urinary excretion.

The half-life of Videx ranges from 1.5 to 4 hours.

Videx is eliminated primarily by urinary excretion as ddI. Less than 5% of the dose is excreted unchanged in the urine.