Underprescribing may take the form of:
(1) failing to prescribe a drug that is indicated and appropriate
(2) prescribing less than what is needed for full effect (by dose, route, and/or schedule)
Reasons for underprescribing:
(1) cost
(2) age of the patient
(3) concerns about adverse effects
(4) concerns about drug interactions
(5) concerns about abusing the drug
(6) lack of knowledge about the drug
(7) concerns about polypharmacy
An initial prescription error may be continued if there are problems in clinical follow-up or failures to monitor drug levels.
A patient may avoid a medication or not take as much as needed for very similar reasons.