2020 Edition 3
clinical initiatives, research and current updates in treatment
Special Edition World Antimicrobial Awareness Week is from 18 - 24 November 2020. It aims to raise awareness of antimicrobial resistance and promote the responsible use of antimicrobials.
How long is a “course” of antibiotics? Glenn Valoppi, Antimicrobial Stewardship Pharmacist – Slade Pharmacy, Epworth Hospital Richmond Antibiotics are commonly prescribed for the treatment and prevention of infectious diseases. The most appropriate drug, dose, route of administration and duration of therapy should be used to achieve the best outcome for the patient while minimising the risk of harm. These potential harms include adverse effects (e.g. nausea, hepatitis), development of superinfections (yeasts, C.difficile), and colonisation with resistant organisms (e.g. ESBL E.coli, vancomycin-resistant E.faecium (VRE)).
For how long are antibiotics actually needed? Recommendations for the duration of therapy of antibiotics might be based on patient outcomes, for example continuing an antiviral drug such as ganciclovir until viral loads in the blood are under control. Other recommendations are often based on research comparing different lengths of therapy before stopping treatment or changing from injectable to oral options. These studies often compare a new (shorter) treatment plan with current standard care. If there is no worse outcome for patients using a shorter course, this may lead to a change in treatment guidelines. The likelihood of treatment success is the same, but the risk of harm from the antibiotic is
reduced. There are additional potential benefits in terms of reduced treatment costs, reduced lengths of stay, and reduced IV-line related complications related to intravenous treatment. Research is emerging indicating that clinical outcomes are similar between short and long courses of antibiotics for many common infections. To determine what the most appropriate duration might be, it is important to know what the diagnosis is for your patient.
How much longer does my patient need treatment with antibiotics? The efficacy of antibiotics is related to how much of the drug gets to the site of infection rather than the actual administration method. Every day of treatment with an active drug should be counted when reviewing the patient, regardless of the route. Consider a patient with severe pyelonephritis caused by E.coli who is now stable and ready for discharge on oral antibiotics. They received 2 days of IV piperacillin-tazobactam started in the Emergency Department; followed by 3 days of IV ceftriaxone in hospital once the microbiology findings were reported. Treatment was then de-escalated to oral amoxicillin for the last 2 days. Guidelines suggest a total treatment duration of 10 to 14 days for severe pyelonephritis. The
discharge prescription should specify for how long to continue oral antibiotics; for a further 3 to 7 days only.
Completing the course Once a diagnosis is clear, and the patient is improving, a treatment duration (in days) can be tailored to the patient. Continuing therapy until this point might be considered ‘Completing the Course’. Continuing antibiotics until a standard packet is emptied may not achieve this. A standard pack size cannot be the right fit for all patients; who may be taking different numbers of pills per day (e.g. clindamycin), have different recommended treatment durations (e.g. cystitis vs. osteomyelitis), or who have already received part of the treatment (initial IV therapy, or imprest supply). Some commercial pack sizes, or PBS quantities, are not necessarily a good fit for recommended therapy. Patients may require more than one pack of amoxicillin or clindamycin capsules to achieve the right dose for the right duration. A standard pack of seven tablets of trimethoprim is more than required for cystitis in most women, an appropriate number for cystitis in most men, and too few for treatment of prostatitis.
Where else to look for information? Useful summaries have been recently Continued on page 2