Zidovudine (Retrovir) Product Label Updated with New Dosing Recommendations for Children with HIV

Zidovudine (Retrovir) Tablet

Last week the U.S. Food and Drug Administration (FDA) announced revised product labeling for zidovudine (AZT; Retrovir), reflecting updated dosing recommendations for pediatric patients. HIV positive children may now take zidovudine either twice or three times daily.

Below is the text of the FDA announcement of the change:

HIV/AIDS Update - Retrovir syrup, capsules and tablets label update for twice daily dosing in children 6 weeks to 18 years of age

On September 19, 2008, FDA approved a pediatric efficacy supplement for Retrovir syrup, capsules and tablets allowing for a twice daily dosing regimen in children 6 weeks to 18 years of age. It also provides for dosing by weight in addition to dosing by body surface area.

Previously, Retrovir dosing recommendations for the treatment of HIV in children included three times daily dosing with dose calculated using body surface area. The new label has recommendations for twice daily or three times daily dosing by weight or by body surface area. The new recommendations should allow for more convenient dosing (twice daily) of Retrovir (zidovudine) in children.

The main changes include revisions to the Dosage and Administration section to include twice daily dosing in children as follows.

Pediatric Patients (6 weeks to <18 years of age): Healthcare professionals should pay special attention to accurate calculation of the dose of Retrovir, transcription of the medication order, dispensing information, and dosing instructions to minimize risk for medication dosing errors.

Prescribers should calculate the appropriate dose of Retrovir for each child based on body weight (kg) and should not exceed the recommended adult dose.

Before prescribing Retrovir capsules or tablets, children should be assessed for the ability to swallow capsules or tablets. If a child is unable to reliably swallow a Retrovir capsule or tablet, the Retrovir syrup should be prescribed.

The recommended dosage in pediatric patients 6 weeks of age and older and weighing ? 4 kg is provided in Table 1. Retrovir syrup should be used to provide accurate dosage when whole tablets or capsules are not appropriate.

[Editor's note: b.i.d. = twice daily; t.i.d. = three times daily]

Alternatively, dosing for Retrovir can be based on body surface area (BSA) for each child. The recommended oral dose of Retrovir is 480 mg/m2/day in divided doses (240 mg/m2 twice daily or 160 mg/m2 three times daily). In some cases the dose calculated by mg/kg will not be the same as that calculated by BSA.

Additionally, the label was converted to Physician Labeling Rule (PLR) format to make product labeling more informative and accessible. The pregnancy related sections were modified with the conversion to PLR format to make the data more accessible to clinicians but content was not revised.

Retrovir is a product of GlaxoSmithKline.

9/26/08

Source
R Klein and K Struble. Retrovir syrup, capsules and tablets label update for twice daily dosing in children 6 weeks to 18 years of age. FDA HIV/AIDS Update. September 22, 2008.