Prescribers considering use of zoledronic acid (Aclasta) once-yearly infusion in patients who have osteoporosis will need to weigh up the possible benefits against the relative lack of experience with this drug in osteoporosis.

This month’s NPS RADAR review of the newly PBS-listed drug provides information to help prescribers’ decision-making and to counsel patients.

“Zoledronic acid is an alternative to oral bisphosphonates and may be particularly useful for those patients who cannot tolerate or who have difficulty taking oral bisphosphonates, however, the dosing convenience of an annual infusion will be somewhat limited if patients need calcium and vitamin D supplements as these will still need to be taken daily,” NPS Deputy CEO, Karen Kaye, said.

“Prescribers need to balance the possible risks and benefits of any new drug,” Ms Kaye said.

“Like other bisphosphonates, zoledronic acid has been associated with serious, often delayed, adverse effects, including renal dysfunction, inflammatory ocular disorders, osteonecrosis of the jaw and possibly atrial fibrillation.

“Most safety data for zoledronic acid are from its use at higher doses for malignancy, so there’s relatively limited experience with its use in osteoporosis. We don’t yet know if the risk of osteonecrosis of the jaw differs from that with oral bisphosphonates in people treated for  steoporosis,” Ms Kaye said.

Acute-phase reactions, such as fever, myalgia, flu-like illness and headache, frequently occur within three days of infusion.

Before prescribing zoledronic acid, GPs should check if patients have received their first infusion in hospital and should ensure that oral bisphosphonates are stopped.

The importance of patient counselling, particularly to avoid confusion between formulations, is also highlighted in reviews of new once-daily formulations of tramadol (Durotram XR) and quetiapine (Seroquel XR).

“With a number of tramadol formulations now available, with different dosing frequencies and brand names, it’s particularly important to provide clear information to patients to avoid confusion and possible errors,” Ms Kaye said.

“Ensure that patients are aware that tramadol extended-release is a once-daily tablet and advise them not to take any other product containing tramadol while using tramadol extended-release, without speaking to a doctor or pharmacist,” Ms Kaye said.

The quetiapine extended-release tablets come in different strengths from those of the existing immediate-release tablets, and dosing and administration is slightly different.

“There is no compelling reason to switch people who are currently stable on quetiapine immediaterelease tablets to extended-release tablets. Prescribers will need to instruct patients carefully to prevent confusion between the two formulations,” Ms Kaye said.

Consumer reviews of both zoledronic acid and tramadol are available at www.nps.org.au in the latest editions of Medicine Update. These may assist when counselling patients.

ENDS

NPS RADAR provides independent information about new medicines and changes to PBS listings important to GPs, pharmacists and other health professionals involved in primary care management of patients.

For further advice health professionals can call the NPS Therapeutic Advice and Information Service (TAIS) – a medicines information service staffed by specialist drug information pharmacists – on 1300 138 677 Monday to Friday 9am-7pm Eastern Standard Time for the cost of a local call (mobiles may cost more). National Prescribing Service Limited (NPS) is an independent, non-profit organisation for Quality Use of Medicines funded by the Australian Government Department of Health and Ageing.