Videx Side Effects

Generic Name: didanosine

Note: This page contains side effects data for the generic drug didanosine. It is possible that some of the dosage forms included below may not apply to the brand name Videx.

It is possible that some side effects of Videx may not have been reported. These can be reported to the FDA here. Always consult a healthcare professional for medical advice.

For the Consumer

Applies to didanosine: oral capsule delayed release, oral powder for solution, oral powder for suspension, oral tablet chewable

As well as its needed effects, didanosine (the active ingredient contained in Videx) may cause unwanted side effects that require medical attention.

If any of the following side effects occur while taking didanosine, check with your doctor immediately:

Less common
  • Nausea and vomiting
  • stomach pain
  • tingling, burning, numbness, and pain in the hands or feet
Rare
  • Convulsions (seizures)
  • fever and chills
  • shortness of breath
  • skin rash and itching
  • sore throat
  • swelling of the feet or lower legs
  • unusual bleeding and bruising
  • unusual tiredness and weakness
  • yellow skin and eyes
Incidence not known
  • Abdominal or stomach discomfort
  • anxiety
  • black, tarry stools
  • bleeding gums
  • blindness
  • bloating
  • blood in the urine or stools
  • blue-yellow color blindness
  • blurred vision
  • change in the color of the eye
  • chest pain
  • clay colored stools
  • cold sweats
  • coma
  • confusion
  • constipation
  • cool, pale skin
  • cough
  • dark urine
  • decreased appetite
  • decreased vision
  • depression
  • diarrhea
  • difficulty with moving
  • difficulty with swallowing
  • dizziness
  • dry eyes
  • dry mouth
  • eye pain
  • fast heartbeat
  • fast, shallow breathing
  • flushed, dry skin
  • fruit-like breath odor
  • general feeling of discomfort
  • headache
  • hives
  • increased hunger
  • increased thirst
  • increased urination
  • indigestion
  • joint pain
  • light-colored stools
  • loss of appetite
  • loss of consciousness
  • muscle aching, cramping, or pain
  • nervousness
  • nightmares
  • painful or difficult urination
  • pains in the stomach, side, or abdomen, possibly radiating to the back
  • pinpoint red spots on the skin
  • puffiness or swelling of the eyelids or around the eyes, face, lips, or tongue
  • right upper abdominal pain and fullness
  • shakiness
  • sleepiness
  • slurred speech
  • sores, ulcers, or white spots on the lips or in the mouth
  • stomachache
  • sweating
  • swollen glands
  • swollen joints
  • tightness in the chest
  • troubled breathing with exertion
  • unexplained weight loss
  • unsteadiness or awkwardness
  • weakness in the arms, hands, legs, or feet
  • wheezing

Some didanosine side effects may not need any medical attention. As your body gets used to the medicine these side effects may disappear. Your health care professional may be able to help you prevent or reduce these side effects, but do check with them if any of the following side effects continue, or if you are concerned about them:

More common
  • Difficulty with sleeping
  • irritability
  • restlessness
Incidence not known
  • Acid or sour stomach
  • belching
  • excess air or gas in the stomach or intestines
  • full feeling
  • hair loss or thinning of the hair
  • heartburn
  • indigestion
  • lack or loss of strength
  • passing gas
  • redistribution or accumulation of body fat

For Healthcare Professionals

Applies to didanosine: oral delayed release capsule, oral powder for reconstitution, oral tablet chewable

General

The adverse effects of didanosine (the active ingredient contained in Videx) are sometimes difficult to distinguish from the symptomatology observed during the clinical course of AIDS, as well as from the possible adverse effects of other drugs used in the treatment of HIV infection. During the Expanded Access Program (EAP), adverse effects resulted in drug discontinuation in 42% of patients with AIDS and 34% of patients with ARC.

When didanosine is used in combination with other agents with similar toxicities, the incidence of these toxicities may be higher than when didanosine is used alone. Patients treated with didanosine in combination with stavudine, with or without hydroxyurea, may be at an increased risk for pancreatitis and hepatotoxicity, which may be fatal, and severe peripheral neuropathy.

Many of the side effects associated with nucleoside reverse transcriptase inhibitor therapy (myopathy, pancreatitis, liver failure, lactic acidosis, etc.) are attributable to their direct toxic effect on mitochondria which causes decreased mitochondrial energy-generating capacity.

Patients with renal dysfunction may be at increased risk of toxicity due to decreased clearance of didanosine.

Gastrointestinal

The frequency of pancreatitis is dose related. In phase 3 trials with buffered formulations, incidence ranged from 1% to 10% with doses higher than currently recommended and 1% to 7% with recommended doses.

The factors that increase the risk of pancreatitis in patients with HIV infection are an AIDS diagnosis, CD4+ cell count less than 100 cells/mm3, baseline hyperamylasemia, substantial alcohol intake, elevated liver transaminases, concurrent treatment with pancreatotoxic medications, and prior history. Resolution is generally seen 2 to 3 weeks following discontinuation of therapy, although fatal cases have been reported. Permanent discontinuation of didanosine (the active ingredient contained in Videx) in patients developing pancreatitis is suggested, because rechallenge often results in recurrent disease.

A retrospective cohort study evaluated the risk of pancreatitis with didanosine combination therapy. Patients with HIV can develop pancreatitis from the virus itself or from direct toxicity of several antiretroviral drugs.

Gastrointestinal side effects have included diarrhea (up to 70%), nausea (up to 53%), vomiting (30%), elevated lipase (Grades 3 to 4: up to 8%; all Grades: up to 26%), abdominal pain (up to 13%), and pancreatitis (up to 7%). Pancreatitis resulting in death has been reported during clinical trials of didanosine in combination with other antiretroviral agents. During the EAP in which patients received clinically recommended dosages, the incidence at 5 months for pancreatitis, increased amylase, or abdominal pain was 5% to 8%. Anorexia, dyspepsia, flatulence, pancreatitis (including fatal cases), dry mouth, sialoadenitis, and parotid gland enlargement have been reported during postmarketing experience.

Hepatic

Hepatic side effects have included lactic acidosis/severe hepatomegaly with steatosis, hepatic toxicity, and elevated AST (Grades 3 to 4: up to 9%; all Grades: up to 53%), ALT (Grades 3 to 4: up to 9%; all Grades: up to 50%), bilirubin (Grades 3 to 4: up to 16%; all Grades: up to 68%), and gamma-glutamyltransferase (greater than 5 times ULN: up to 5%; all Grades: up to 28%). Fatal hepatic events were reported most often in patients treated with the combination of hydroxyurea, didanosine (the active ingredient contained in Videx) and stavudine. In addition, fulminant hepatitis has been associated with didanosine and has resulted in death. Symptomatic hyperlactatemia/lactic acidosis and hepatic steatosis, noncirrhotic portal hypertension, hepatitis, and liver failure have been reported during postmarketing experience. Hepatotoxicity and hepatic failure resulting in death have been reported during postmarketing experience with hydroxyurea and other antiretroviral agents.

Lactic acidosis and severe hepatomegaly with steatosis, including fatal cases, have been reported with the use of nucleoside analogs alone or in combination with other antiretroviral agents. Caution should be exercised when administering didanosine to any patient with known risk factors for liver disease. However, cases have also been reported in patients with no known risk factors. Fatal lactic acidosis has been reported in pregnant women who received the combination of didanosine and stavudine with other antiretroviral agents.

Hyperlactatemia and lactic acidosis are often a life-threatening and serious concern with the use of didanosine in combination with other antiretrovirals. Lactate elevation is a common issue in patients on stable antiretroviral therapy and increased levels without acidosis may result from increased production, release, or diminished clearance.

HIV reverse transcriptase inhibitors are competitive inhibitors of DNA polymerase and the greatest affinity appears to be in the mitochondria. Depletion of mitochondrial DNA diminishes cellular respiratory function leading to increased production of lactic acid. Excess lactic acid leaks out of the cell into systemic circulation and can progress to lactic acidosis if hydrogen ions drop the blood pH. Additionally, disturbances in metabolic homeostasis with antiretrovirals can cause hypertriglyceridemia and insulin resistance leading to steatohepatitis and decreased liver function.

Hyperlactatemia appears to be more common with didanosine while lactic acidosis is an infrequent occurrence.

In a report following patients on combined therapy with didanosine and tenofovir, one patient developed didanosine-related toxicity characterized by lactic acidosis with liver failure after 3 months on didanosine 200 mg/day with tenofovir.

Safety and efficacy have not been established in HIV-infected patients with significant underlying liver disease. During combination antiretroviral therapy, patients with preexisting liver dysfunction (including chronic active hepatitis) have an increased rate of liver function abnormalities, including severe and potentially fatal hepatic side effects.

Nervous system

Peripheral neuropathy occurred in 16% of patients treated during the EAP. Early trials of didanosine (the active ingredient contained in Videx) therapy reported a higher incidence. Those studies, however, used higher dosages than more recent trials using lower therapeutic dosages and early trials included patients with very advanced HIV disease. One-year rates of developing peripheral neuropathy ranged from 6% to 15% in the latter trials.

Neuropathy presents as tingling, numbness, or pain in the hands or soles of the feet which progresses up the legs. The incidence is higher in patients with a history of neuropathy and/or low CD4+ cell counts (less than 50 cells/mm3). Following discontinuation of didanosine, neuropathy usually resolves within 2 to 12 weeks.

Nervous system side effects have included headache (up to 46%), peripheral neurologic symptoms/neuropathy (up to 26%), insomnia, restlessness, and seizures.

Metabolic

There has been one case report of acute gouty arthritis developing 14 weeks after didanosine (the active ingredient contained in Videx) was added to the treatment regimen of a patient receiving ritonavir, both known to infrequently cause hyperuricemia. The symptoms resolved upon discontinuation of didanosine and a short course of indomethacin.

Metabolic side effects have included elevated alkaline phosphatase (greater than 5 times ULN: up to 4%), amylase (at least 1.4 times ULN: up to 17%; greater than 2 times ULN: up to 8%; all Grades: up to 31%), and uric acid (greater than 12 mg/dL: up to 3%). Hyperuricemia developed in 4% of patients treated during the EAP. At least one case of acute gouty arthritis has been reported. Diabetes mellitus, redistribution/accumulation of body fat (including central obesity, dorsocervical fat enlargement, peripheral wasting, facial wasting, breast enlargement, and "cushingoid appearance"), hypoglycemia, hyperglycemia, and elevated serum uric acid, serum alkaline phosphatase, serum amylase, and serum gamma-glutamyltransferase have been reported during postmarketing experience.

Dermatologic

Dermatologic side effects have included rash (up to 30%), rash/pruritus (up to 9%), and at least one case of cutaneous leukocytoclastic vasculitis. Alopecia has been reported during postmarketing experience.

Hematologic

Hematologic side effects have included anemia, neutropenia, and thrombocytopenia. Leukopenia, anemia, and thrombocytopenia have also been reported during postmarketing experience. Thrombocytopenia and splenomegaly have been reported as early signs of noncirrhotic portal hypertension, which has been reported during postmarketing experience.

Cardiovascular

Cardiovascular side effects have rarely included dyspnea, orthopnea, edema, pericarditis, and left ventricular failure. Underlying cardiomyopathy may have been aggravated by treatment with buffered formulations, which had high sodium content.

Ocular

Diffuse dysfunction of the retinal epithelium has been reported in two patients during therapy with didanosine (the active ingredient contained in Videx) Both patients experienced bilateral visual deficit including night blindness and a peripheral visual fold reduction. Symptoms were first noted after 31 and 34 weeks of therapy. Deficits in both patients appeared to be partially reversible upon discontinuation of didanosine.

Ocular side effects have included retinal changes and optic neuritis. Diffuse dysfunction of the retinal epithelium with bilateral visual deficit (including night blindness and a peripheral visual fold reduction) has been reported. Dry eyes, retinal depigmentation, and optic neuritis have been reported during postmarketing experience.

Other

Other side effects have included abdominal pain, asthenia, chills/fever, and pain during postmarketing experience.

Musculoskeletal

Musculoskeletal side effects have included myalgia (with or without increases in creatine kinase), rhabdomyolysis (including acute renal failure and hemodialysis), arthralgia, and myopathy during postmarketing experience.

Hypersensitivity

Hypersensitivity side effects have included anaphylactoid reaction during postmarketing experience.

Immunologic

Immunologic side effects have included immune reconstitution syndrome. Autoimmune disorders (e.g., Graves' disease, polymyositis, and Guillain-Barre syndrome) have been reported in the setting of immune reconstitution.

Endocrine

Endocrine side effects are uncommon but have included hypertriglyceridemia, impaired glucose tolerance, hyperglycemia, and hypoglycemia. Insulin-dependent diabetes mellitus has also been reported.

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