Didanosine dosage

Extensive serial audiological studies in an HIV-infected child showed high-frequency hearing loss after 19 months of combined treatment with zidovudine and didanosine (dosages unknown), which were started at 24 months of age (9). Normal tympanograms indicated that this hearing loss was sensorineural. 

Boelaert JR, Dorn GM, Huitema ADR, Beijnen JH, Lange JMA. The boosting of didanosine by allopurinol permits a halving of the didanosine dosage. AIDS (2002) 16, 2221-3. 

Didanosine EC (Videx EC) - Didanosine EC has not been studied in pediatric patients. Please consult the complete prescribing information for didanosine buffered formulation and pediatric powder for oral solution for dosage and administration of didanosine to pediatric patients. 

Peripheral neuropathy occurs in up to 50% of patients taking zalcitabine. Stomatitis, esophageal ulceration, hepatotoxicity, rash, and pancreatitis may occur. Zalcitabine should be used with caution in individuals with a history of pancreatitis, liver disease, or alcohol abuse. Dosage adjustment is necessary for individuals with renal impairment. Zalcitabine should not be used in combination with didanosine, lamivudine, or stavudine. 

Jablonowski H. Didanosin als Kapsel. Bewahrtes Medikament in neuer Form. [Didanosine as a capsule. A reliable drug in a new dosage form.] MMW Fortschr Med 2001 143(Suppl l) 92-5. 

Established interactions. With the NRTTs that are actively excreted via the kidneys (e.g. lamivudine, stavudine, and zaicitabine), it is unlikely that dosage alterations are necessary unless the patient has renal impairment. However, when both drugs are needed, patients should be closely monitored for signs of toxicity. Moreover, the UK manufacturer of lamivudine recommends that the use of lamivudine with high-dose co-trimoxazole for the treatment of Pneumocystis pneumonia and toxoplasmosis should be avoided. Since renal clearance represents only 20 to 30% of the total clearance of zidovudine, the authors of two of these reports " suggest that this interaction is unlikely to be clinically important for zidovudine unless the glucuronidation by the liver is impaired by liver disease or other drugs. Didanosine also does not appear to interact to a clinically relevant extent. 

Buffered didanosine 400 mg was given to 14 healthy subjeets, with and without allopurinol 300 mg daily for 7 days. The allopurinol signifieantly inereased didanosine absorption, shown by a twofold inerease in the AUC and a 69% rise in its maximum serum levels. Similar findings were seen in HIV-positive subjects. Moreover, the addition of allopurinol 300 mg daily allowed the dosage of didanosine to be halved from 400 mg to 200 mg daily in 4 patients taking buffered didanosine, hydroxyearbamide and chloroquine. Didanosine plasma levels and antiviral effieaey were unchanged. ... 

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