One in 3 prescriptions are never redeemed: primary nonadherence in an outpatient clinic.

Background: Despite being essential to medication adherence, redemption of initial prescriptions (ie, primary adherence) has been investigated only sparsely.

Objectives: The objectives were to determine the frequency and risk factors for primary nonadherence among outpatients with dermatologic conditions.

Methods: Every 15th day during 2006, all patients receiving a prescription for an initial treatment with a previously untried medication were studied. Redemptions were traced in an electronic register after 4 weeks. Exclusions were a result of identical treatments within the last 6 months or hospitalizations within 4 weeks.

Results: In all, 30.7% of the 322 eligible patients did not collect their medication. Patients with psoriasis were least adherent with nearly 50% of the prescriptions being unredeemed.

Limitations: Only initial prescriptions for previously untried medications issued to hospital outpatients were studied.

Conclusions: For the clinician, primary nonadherence is an essential differential diagnosis when a given therapy fails.