Question

Which of the following is the most appropriTe breakthrough dose for a patient receiving oral extended morphine 60 mg q 12 hours? my professor said answer is morphine elixir 4 mg PO but not sure why

Answer 1

Breakthrough dose is ordered using immediate release tablets or oral solution. Usually, the dose given is 1/24th of daily morphine taken hourly p.r.n. or 1/12th of daily morphine dose q.2 hours p.r.n. A higher or lower breakthrough dose is given as needed depending on the patient response. Here since the patient is receiving morphine 60 mg q.12 hours, i.e. 120 mg daily, the breakthrough dose is 120 * 1/24, which is 5 mg. The choice given here is 4 mg, which is the nearest one and maybe 4 is a lower breakthrough dose given depending on the patient response.