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a nucleoside analogueantiretroviral agent used for the treatment of advanced human immunodeficiency virus infection and acquired immunodeficiency syndrome; administered orally.
Miller-Keane Encyclopedia and Dictionary of Medicine, Nursing, and Allied Health, Seventh Edition. © 2003 by Saunders, an imprint of Elsevier, Inc. All rights reserved.

didanosine (ddI, 2,3-dideoxyinosine)

Videx, Videx EC

Pharmacologic class: Nucleoside reverse transcriptase inhibitor

Therapeutic class: Antiretroviral, antiviral

Pregnancy risk category B

FDA Box Warning

• Pancreatitis has occurred when drug was used alone or in combination regimens in treatment-naive or treatment-experienced patients. Suspend therapy in patients with suspected pancreatitis; discontinue in patients with confirmed pancreatitis.

• Drug may cause lactic acidosis and severe hepatomegaly with steatosis when used alone or in combination with other antiretrovirals. Fatal lactic acidosis has occurred in pregnant women receiving didanosine-stavudine combination with other antiretrovirals. In pregnant patients, use this combination with caution and only if benefit clearly outweighs risk.


Inhibits replication of human immunodeficiency virus (HIV) by disrupting synthesis of DNA polymerase, an enzyme crucial to DNA and RNA formation


Capsules (delayed-release): 125 mg, 200 mg, 250 mg, 400 mg

Powder for oral solution (pediatric): 2 g in 4-oz glass bottle, 4 g in 8-oz glass bottle

Indications and dosages

HIV infection

Adults weighing 60 kg (132 lb) or more: 400 mg (capsules) P.O. once daily

Adults weighing less than 60 kg (132 lb): 250 mg (capsules) P.O. once daily

Children: 120 mg/m2 (powder for oral solution, pediatric) P.O. q 12 hours

Dosage adjustment

• Renal impairment


• Hypersensitivity to drug

• Concurrent use of allopurinol or ribavirin


Use cautiously in:

• renal or hepatic impairment, peripheral neuropathy, hyperuricemia

• elderly patients

• pregnant or breastfeeding patients

• children.


• Know that drug is usually given in conjunction with other antiretrovirals.

• Give on empty stomach 30 minutes before or 2 hours after a meal.

• Don't administer with fruit juice.

• Know that pharmacist must prepare pediatric powder for oral solution by diluting with water and antacid to a concentration of 10 mg/ml.

• Be aware that delayed-release capsules aren't intended for use in children.

Adverse reactions

CNS: dizziness, anxiety, abnormal thinking, hypoesthesia, agitation, confusion, hypertonia, asthenia, peripheral neuropathy, seizures, coma

CV: peripheral coldness, palpitations, hypotension, bradycardia, weak pulse, pseudoaneurysm, incomplete atrioventricular (AV) block, complete AV block, nodal arrhythmias, ventricular tachycardia, thrombophlebitis, embolism

EENT: diplopia, abnormal vision, ocular hypotony, iritis, retinal detachment

GI: nausea, vomiting, diarrhea, abdominal enlargement, dyspepsia, ileus, GI reflux, hematemesis, dysphagia, dry mouth, pancreatitis

GU: urinary retention, frequency, or incontinence; dysuria; cystalgia; prostatitis; renal dysfunction; nephrotoxicity

Hematologic: anemia, leukocytosis, thrombocytopenia, bleeding, neutropenia

Hepatic: hepatomegaly with steatosis, noncirrhotic portal hypertension

Metabolic: diabetes mellitus, hyperkalemia, lactic acidosis, noncirrhotic portal hypertension

Musculoskeletal: muscle contractions

Respiratory: pneumonia, crackles, rhonchi, bronchitis, pleurisy, dyspnea, wheezing, pleural effusion, pulmonary edema, pulmonary embolism, bronchospasm

Skin: diaphoresis, pallor, rash, urticaria, pruritus, bullous eruption, petechiae, cellulitis, abscess

Other: edema, development of human antichimeric antibodies


Drug-drug. Allopurinol, ganciclovir (oral), ribavirin, tenofovir: increased didanosine blood level

Amprenavir, delavirdine, indinavir, ritonavir, saquinavir: altered didanosine pharmacokinetics

Antacids, other drugs that increase gastric pH: increased risk of didanosine toxicity

Co-trimoxazole, pentamidine: increased risk of pancreatic toxicity

Dapsone, fluoroquinolones, ketoconazole: decreased blood levels of these drugs

Itraconazole: decreased itraconazole blood level

Methadone: 50% decrease in didanosine blood level

Drug-diagnostic tests. Alanine aminotransferase, alkaline phosphatase, aspartate aminotransferase, bilirubin, uric acid: increased levels

Granulocytes, hemoglobin, platelets, white blood cells: decreased values

Drug-food. Any food: decreased rate and extent of drug absorption

Patient monitoring

Monitor patient for signs and symptoms of pancreatitis. Withhold drug in patients with signs or symptoms of pancreatitis and discontinue drug in patients with confirmed pancreatitis.

Monitor patient for early signs and symptoms of portal hypertension (thrombocytopenia, splenomegaly). Discontinue drug in patients with evidence of noncirrhotic portal hypertension.

Assess carefully for signs and symptoms of lactic acidosis, such as dizziness, light-headedness, and bradycardia.

• Monitor for signs and symptoms of peripheral neuropathy.

• In patients with renal impairment, watch for drug toxicity and hypermagnesemia (suggested by muscle weakness and confusion).

Patient teaching

• Tell patient to take drug on empty stomach.

• Advise patient using buffered powder to mix it with water, not juice, and to let powder dissolve for several minutes before taking.

Instruct patient to immediately report abdominal pain, nausea, vomiting, tiredness, fast or irregular heartbeats, easy bruising, difficulty breathing, yellowing of skin or eyes, or dark urine.

• As appropriate, review all other significant and life-threatening adverse reactions and interactions, especially those related to the drugs, tests, and foods mentioned above.

McGraw-Hill Nurse's Drug Handbook, 7th Ed. Copyright © 2013 by The McGraw-Hill Companies, Inc. All rights reserved


(dĭ-dăn′ə-sēn′, -sĭn)
See DDI.
The American Heritage® Medical Dictionary Copyright © 2007, 2004 by Houghton Mifflin Company. Published by Houghton Mifflin Company. All rights reserved.


2',3'-dideoxyinosine, ddI, Videx AIDS A purine analogue that inhibits HIV-1's reverse transcriptase, which may be more effective than zidovudine and may be an anti-retroviral nucleoside of first choice– ddI is associated with an ↑ in CD4–T-helper cells, and ↓ p24 antigen–an indicator of HIV in the blood; ddI is better tolerated than zidovudine and causes less myelosuppression Side effects Peripheral neuropathy, pancreatitis Lab Hyperuricemia, ↑ aminotransferases. See AIDS, Zidovudine.
McGraw-Hill Concise Dictionary of Modern Medicine. © 2002 by The McGraw-Hill Companies, Inc.


A nucleoside analogue drug used in the treatment of AIDS. The drug is on the WHO official list. A brand name is Videx.
Collins Dictionary of Medicine © Robert M. Youngson 2004, 2005