Prescription Writing Flashcards
7 cards from real PSA practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Prescription Writing flashcards as text
Why should a 'trailing zero' (e.g., writing '1.0 mg' instead of '1 mg') never appear on a prescription?
Answer: It can be misread as '10 mg,' causing a tenfold overdose
A trailing zero after the decimal point (e.g., 1.0 mg) risks being misread as 10 mg if the decimal point is not seen, potentially causing a dangerous tenfold dosing error.
The abbreviation 'U' for units is on the Institute for Safe Medication Practices (ISMP) 'Do Not Use' list. What dangerous misinterpretation can occur?
Answer: 'U' can be misread as '0,' turning '10 U' into '100'
The abbreviation 'U' for units can be misread as the number '0,' so '10 U' of insulin could be dispensed as 100 units, a tenfold overdose.
Which error is most likely if a prescriber writes 'QD' ambiguously in a handwritten prescription?
Answer: Both A and B are plausible misreads depending on handwriting
Ambiguously written 'QD' can be misread as 'QID' (quadrupling the dose) or 'QOD' (halving it), which is why ISMP recommends writing 'daily' or 'every other day' in full.
The abbreviation 'MS' on a prescription is considered dangerous because it is ambiguous. What two drugs does it represent?
Answer: Morphine sulfate and magnesium sulfate
'MS' can stand for either morphine sulfate (an opioid analgesic) or magnesium sulfate (used in eclampsia and as a laxative), two drugs with vastly different indications and dose ranges.
A prescription written for 'warfarin 2.5 mg' is presented, but the prescriber's handwriting makes the dose look like '25 mg.' This is an example of which error type?
Answer: Wrong dose error due to illegibility
Illegible handwriting that obscures a decimal point or zero can cause a wrong dose error, here potentially causing life-threatening anticoagulant toxicity.
When writing a prescription for a drug with a narrow therapeutic index (e.g., digoxin), which practice is most important to prevent dosing errors?
Answer: Writing the dose in both numbers and words (e.g., '0.125 mg [one hundred twenty-five micrograms]')
For narrow therapeutic index drugs, writing the dose in both numerals and spelled-out words provides a double-check, reducing the risk of misreading or transcription errors.
Which prescribing practice should be avoided to prevent confusion between micrograms and milligrams?
Answer: Writing the Greek letter μg for micrograms
The Greek symbol μg can be misread as 'mg' (milligrams), creating a 1,000-fold dosing error; ISMP recommends spelling out 'micrograms' or using 'mcg' instead.