The Medication Possession Ratio (MPR) is the ratio of a patient's drug supply based on pharmacy records to the amount needed for continuous therapy. This can help identify patients who may be nonadherent to drug therapy.
medication possession ratio =
= (number of days covered by drugs received) / (number of days that need to be covered for continuous drug therapy)
Ratio |
Interpretation |
---|---|
< 0.8 |
poor adherence |
0.8 - 1.1 |
good adherence |
> 1.1 |
excess drug refills |
Some causes for poor adherence:
(1) free drug samples
(2) prescription filled at another pharmacy
(3) admitted to the hospital for a prolonged period
Some causes for excess drug refills:
(1) lost medication
(2) change in prescription with excess drug provided
(3) diverting medication (if abuse potential)
Limitations:
• This is a relatively crude screening tool. A person could have filled a prescription and not taken the medication.
• This could be useful for monitoring a patient on a long-term medication at stable dosing.
Purpose: To compare the amount of drug received by a patient to the amount needed for continuous therapy over a given period.
Specialty: Pharmacology, clinical
Objective: dosage calculations, dosage adjustments, drug levels
ICD-10: A00-B99, C00-D49, D50-D89, E00-E89, F01-F99, G00-G99, H00-H59, H60-H95, I00-I99, J00-J99, K00-K95, M00-M99, N00-N99,