Videx
Videx - General Information
A dideoxynucleoside compound in which the 3&
Pharmacology of Videx
Videx is a nucleoside reverse transcriptase inhibitor (NRTI) with activity against Human Immunodeficiency Virus Type 1 (HIV-1). Videx differs from other nucleoside analogues, as it does not have any of the regular bases, instead it has hypoxanthine attached to the sugar ring. Videx is phosphorylated to active metabolites that compete for incorporation into viral DNA. They inhibit the HIV reverse transcriptase enzyme competitively and act as a chain terminator of DNA synthesis. Videx is effective against HIV, and usually used in combination with other antiviral therapy. Switching from long term AZT treatment to didanosine has been shown to be beneficial. Videx has weak acid stability and therefore, it is often combined with an antacid.
Videx for patients
VIDEX EC
(generic name= didanosine also known as ddl)
VIDEX EC (didanosine) Delayed-Release Capsules
Enteric-Coated Beadlets
What is VIDEX EC?
VIDEX EC (pronounced VY dex ee see) is a prescription medicine used in combination with other drugs to treat adults who are infected with HIV (the human immunodeficiency virus, the virus that causes AIDS). VIDEX EC belongs to a class of drugs called nucleoside analogues. By reducing the growth of HIV, VIDEX EChelps your body maintain its supply of CD4 cells, which are important for fighting HIV and other infections.
VIDEX EC will not cure your HIV infection. At present there is no cure for HIV infection. Even while taking VIDEX EC, you may continue to have HIV-related illnesses, including infections with other disease-producing organisms. Continue to see your doctor regularly and report any medical problems that occur.
VIDEX EC does not prevent a patient infected with HIV from passing the virus to other people. To protect others, you must continue to practice safe sex and take precautions to prevent others from coming in contact with your blood and other body fluids.
There is limited information on the antiviral response of long-term use of VIDEX EC.
In VIDEX EC, an enteric coating is used to protect the medicine while it is in your stomach since stomach acids can break it down. The enteric coating dissolves when the medicine reaches your small intestine.
Who should not take VIDEX EC?
Do not take VIDEX EC if you are allergic to any of its ingredients, including its active ingredient, didanosine, and the inactive ingredients. Tell your doctor if you think you have had an allergic reaction to any of these ingredients.
Because it has only been studied in adults, VIDEX EC is not recommended for children.
How should I take VIDEX EC?
How should I store it?
VIDEX EC (didanosine) should only be taken once daily. Your doctor will determine your dose based on your body weight, kidney and liver function, other medicines you are taking, and any side effects that you may have had with VIDEX EC or other medicines. Take VIDEX EC on an empty stomach. Do not take VIDEX EC with food. Swallow the capsule whole; do not open it. Try not to miss a dose, but if you do, take it as soon as possible. If it is almost time for the next dose, skip the missed dose and continue your regular dosing schedule.
Store capsules in a tightly closed container at room temperature away from heat and out of the reach of children and pets.
If you have kidney disease
If your kidneys are not working properly, your doctor will need to do regular tests to check how they are working while you take VIDEX EC. Your doctor may also lower your dosage of VIDEX EC.
What should I do if someone takes an overdose of VIDEX EC?
If someone may have taken an overdose of VIDEX EC, get medical help right away. Contact their doctor or a poison control center.
What should I avoid while taking VIDEX EC?
Alcohol. Do not drink alcohol while taking VIDEX EC since alcohol may increase your risk of pancreatitis (pain and inflammation of the pancreas) or liver damage.
Other medicines. Other medicines, including those you can buy without a prescription, may interfere with the actions of VIDEX EC or may increase the possibility or severity of side effects. Do not take any medicine, vitamin supplement, or other health preparation without first checking with your doctor.
Pregnancy. It is not known if VIDEX EC can harm a human fetus. Also, pregnant women have experienced serious side effects when taking didanosine (the active ingredient in VIDEX EC) in combination with ZERIT (stavudine), also known as d4T, and other HIV medicines. VIDEX EC should be used during pregnancy only after discussion with your doctor. Tell your doctor if you become pregnant or plan to become pregnant while taking VIDEX EC.
Nursing. Studies have shown didanosine (the active ingredient in VIDEX EC)is in the breast milk of animals getting the drug. It may also be in human breast milk. The Centers for Disease Control and Prevention (CDC) recommends that HIV-infected mothers not breast-feed. This should reduce the risk of passing HIV infection to their babies and the potential for serious adverse reactions in nursing infants. Therefore, do not nurse a baby while taking VIDEX EC.
What are the possible side effects of VIDEX EC?
Pancreatitis. Pancreatitis is a dangerous inflammation of the pancreas that may cause death. Tell your doctor right away if you develop stomach pain, nausea, or vomiting. These can be signs of pancreatitis. Before starting VIDEX EC therapy, let your doctor know if you have ever had pancreatitis. This condition is more likely to happen in people who have had it before. It is also more likely in people with advanced HIV disease. However, it can occur at any stage of HIV disease. It may be more common in patients with kidney problems, those who drink alcohol, and those who are also treated with stavudine or hydroxyurea. If you get pancreatitis, your doctor will tell you to stop taking VIDEX EC.
Lactic acidosis, severe liver enlargement, and liver failure, including deaths, have been reported among patients taking VIDEX EC (including pregnant women). Symptoms that may indicate a liver problem are:
• feeling very weak, tired, or uncomfortable,
• unusual or unexpected stomach discomfort,
• feeling cold,
• feeling dizzy or lightheaded,
• suddenly developing a slow or irregular heartbeat.
Lactic acidosis is a medical emergency that must be treated in a hospital.
If you notice any of these symptoms or if your medical condition changes, stop taking VIDEX EC and call your doctor right away. Women, overweight patients, and those who have been treated for a long time with other medicines used to treat HIV infection are more likely to develop lactic acidosis. Your doctor should check your liver function periodically while you are taking VIDEX EC. You should be especially careful if you have a history of heavy alcohol use or a liver problem.
Vision changes. VIDEX EC may affect the nerves in your eyes. Because of this, you should have regular eye examinations. You should also report any changes in vision to your doctor right away. This includes, for example, seeing colors abnormally or blurred vision.
Peripheral neuropathy. This is a problem with the nerves in your hands or feet. The nerve problem may be serious.
Tell your doctor right away if you have continuing numbness, tingling, or pain in the feet or hands.
Before starting VIDEX EC therapy, let your doctor know if you have ever had peripheral neuropathy. This condition is more likely to happen in people who have had it before. It is also more likely in patients taking medicines that affect the nerves and in people with advanced HIV disease. However, it can occur at any stage of HIV disease. If you get peripheral neuropathy, your doctor will tell you to stop taking VIDEX EC. After stopping VIDEX EC, the symptoms may get worse for a short time and then get better. Once symptoms of peripheral neuropathy go away completely, you and your doctor should decide if starting VIDEX EC is right for you. If so, you might be started at a lower dose.
Special note about other medicines. If you take VIDEX EC along with other medicines with similar side effects, you may increase the chance of having these side effects. For example, using VIDEX EC in combination with other medicines that may cause pancreatitis, peripheral neuropathy, or liver problems (including stavudine and hydroxyurea) may increase your chance of having these side effects.
Other side effects
The most common side effects in adults taking VIDEX EC in combination with other HIV drugs included diarrhea, nausea, headache, vomiting, and rash.
Changes in body fat have been seen in some patients taking antiretroviral therapy. These changes may include increased amount of fat in the upper back and neck ("buffalo hump"), breast, and around the trunk. Loss of fat from the legs, arms, and face may also happen. The cause and long-term health effects of these conditions are not known at this time.
Inactive Ingredients
Carboxymethylcellulose sodium 12, diethyl phthalate, methacrylic acid copolymer, sodium hydroxide, sodium starch glycolate, talc, colloidal silicon dioxide, gelatin, sodium lauryl sulfate, and titanium dioxide.
This medicine was prescribed for your particular condition. Do not use VIDEX EC for another condition or give it to others. Keep VIDEX EC and all medicines out of the reach of children. Throw away VIDEX EC when it is outdated or no longer needed by flushing it down the toilet or pouring it down the sink.
This summary does not include everything there is to know about VIDEX EC. Medicines are sometimes prescribed for purposes other than those listed in a Patient Information Leaflet. If you have questions or concerns, or want more information about VIDEX EC, your physician and pharmacist have the complete prescribing information upon which this leaflet is based. You may want to read it and discuss it with your doctor or other healthcare professional. Remember, no written summary can replace careful discussion with your doctor.
Videx Interactions
Coadministration of VIDEX with drugs that are known to cause pancreatitis may increase the risk of this toxicity (see WARNINGS) and should be done with extreme caution, only if other alternatives are not available, and only if clearly indicated. Neuropathy has occurred more frequently in patients with a history of neuropathy or neurotoxic drug therapy, including stavudine, and these patients may be at increased risk of neuropathy during VIDEX therapy (see ADVERSE REACTIONS).
Allopurinol: The AUC of didanosine was increased about 4-fold when allopurinol at 300 mg/day was coadministered with a single 200-mg dose of VIDEX to two patients with renal impairment (CLcr=15 and 18 mL/min). The effects of allopurinol on didanosine pharmacokinetics in subjects with normal renal function are not known.
Antacids: Concomitant administration of antacids containing magnesium or aluminum with VIDEX Chewable/Dispersible Buffered Tablets or Pediatric Powder for Oral Solution may potentiate adverse events associated with the antacid components.
Drugs Whose Absorption Can Be Affected by the Level of Acidity in the Stomach: Drugs such as ketoconazole and itraconazole should be administered at least 2 hours prior to dosing with VIDEX.
Ganciclovir: Administration of VIDEX 2 hours prior to or concurrent with oral ganciclovir was associated with a 111 (114)% increase in the steady-state AUC of didanosine (n = 12). A 21 (17)% decrease in the steady-state AUC of ganciclovir was observed when VIDEX was administered 2 hours prior to ganciclovir, but not when the two drugs were administered simultaneously (n = 12).
Quinolone Antibiotics: VIDEX should be administered at least 2 hours after or 6 hours before dosing with ciprofloxacin because plasma concentrations of ciprofloxacin are decreased when administered with antacids containing magnesium, calcium, or aluminum. In eight HIV-infected patients, the steady-state AUC of ciprofloxacin was decreased an average of 26% (95% CI = 14%, 37%) when ciprofloxacin was administered 2 hours prior to a marketed chewable/dispersible tablet formulation of VIDEX. The AUC of ciprofloxacin was decreased an average of 15-fold in 12 healthy subjects given ciprofloxacin and didanosine-placebo tablets concurrently. In a single subject given one dose of ciprofloxacin 2 hours after a dose of didanosine-placebo tablets, a greater than 50% reduction in the AUC of ciprofloxacin was observed.
Plasma concentrations of quinolone antibiotics are decreased when administered with antacids containing magnesium, calcium, or aluminum. The optimal dosing interval for coadministration with VIDEX should be determined by consulting the appropriate quinolone package insert.
Interactions with Other Antiretroviral Drugs: Significant decreases in the AUC of delavirdine (20%) and indinavir (84%) occurred following simultaneous administration of these agents with VIDEX. To avoid this interaction, delavirdine or indinavir should be given 1 hour prior to dosing with VIDEX. The pharmacokinetics of nelfinavir are not altered to a clinically significant degree when it is administered with a light meal 1 hour after VIDEX.
Videx Contraindications
VIDEXEC (didanosine) is contraindicated in patients with previously demonstrated clinically significant hypersensitivity to any component of the formulation.
Additional information about Videx
Videx Indication: For use, in combination with other antiretroviral agents, in the treatment of HIV-1 infection in adults.
Mechanism Of Action: Videx (ddI) is metabolized intracellularly by a series of cellular enzymes to its active moiety, dideoxyadenosine triphosphate (ddATP), which inhibits the HIV reverse transcriptase enzyme competitively by competing with natural dATP. It also acts as a chain terminator by its incorporation into viral DNA as the lack of a 3'-OH group in the incorporated nucleoside analogue prevents the formation of the 5' to 3' phosphodiester linkage essential for DNA chain elongation, and therefore, the viral DNA growth is terminated.
Drug Interactions: Ganciclovir The antiviral agent increases the effect and toxicity of didanosine
Tenofovir Tenofovir increases the effect and toxicity of didanosine
Tipranavir Videx EC levels may be reduced
Zalcitabine Additive toxicities (peripheral neuropathy)
Valganciclovir The antiviral agent increases the effect and toxicity of didanosine
Food Interactions: Avoid alcohol.
Take on empty stomach: 1 hour before or 2 hours after meals.
Generic Name: Didanosine
Synonyms: DDI; Dideoxyinosine
Drug Category: Anti-HIV Agents; Antimetabolites; Reverse Transcriptase Inhibitors
Drug Type: Small Molecule; Approved
Other Brand Names containing Didanosine: Videx; Videx EC;
Absorption: Rapidly absorbed (bioavailability 30-40%) with peak plasma concentrations appearing within 0.5 and 1.5 hrs.
Toxicity (Overdose): Side effects include pancreatitis, peripheral neuropathy, diarrhea, hyperuricemia and hepatic dysfunction
Protein Binding: Low (<5%)
Biotransformation: Rapidly metabolized intracellularly to its active moiety, 2,3-dideoxyadenosine-5-triphosphate (ddA-TP). It is then further metabolized hepatically to yield hypoxanthine, xanthine, and uric acid.
Half Life: 30 minutes in plasma and more than 12 hours in intracellular environment.
Dosage Forms of Videx: Powder, for solution Oral
Tablet Oral
Capsule, coated Oral
Chemical IUPAC Name: 9-[(2R,5S)-5-(hydroxymethyl)oxolan-2-yl]-3H-purin-6-one
Chemical Formula: C10H12N4O3
Didanosine on Wikipedia: https://en.wikipedia.org/wiki/Didanosine
Organisms Affected: Human Immunodeficiency Virus
