A point-prevalence study of off-label medication use in an Australian adult tertiary intensive care unit

Medications prescribed for indications or at doses, frequencies or durations not approved by the Australian Therapeutic Goods Administration are considered "off- label". Critical illness makes seeking consent for off-label medication use impractical. We aimed to characterise the extent of off-label medication use in a tertiary medical- surgical intensive care unit (ICU) by auditing the electronic health records of all patients admitted over a one-month period. We found 25.4% of 2292 prescriptions made for 142 patients were off-label. Eighty-one (37.2%) of the total of 218 different prescribed medications were used at least once for an off-label indication. Medications commonly prescribed off-label included antacids (pantoprazole, esomeprazole), analgesics (fentanyl, morphine, ketamine, pregabalin), anticonvulsants (levetiracetam), antibiotics (cefazolin, erythromycin), antipsychotics (quetiapine, haloperidol), and cardiovascular agents (metoprolol, clonidine). Nearly all patients (88.0%) received at least one off-label medication during their ICU stay. Most off- label medications were used for conventional (albeit not licensed) reasons, but nine out of 81 (11.1%) were not; for example, acetazolamide for hypertension, aminophylline for oliguria, and dexmedetomidine for seizures. Recognising the challenges of formally registering an indication with the Therapeutic Goods Administration, but also the value of reducing the incidence of medications used for potentially incorrect purposes, we suggest guideline endorsement of what constitutes standard critical care practice as an alternative to regulatory control.