Where more than one prescription of the same chemical entity was available, these prescriptions were counted only once; different chemical entities within the same drug class were counted separately.
If within the calculated duration a new prescription of the same AED class was issued, exposure was considered continuous, lasting until the last day of the last prescription.
Patients were required to have a second prescription of the same insulin within 180 days and to be free of cancer.
A 'new prescription' was defined as a prescription without any preceding prescription of the same drug substance recorded for that patient in a period of 13 months leading up to the prescription of interest.
The subsequent optical correction is provided by the use of aphakic spectacles which may be given as standard power of +10 to + 12 Dioptres or the exact prescription of the same may be given.
'A first dispensing' was defined as the delivery of a drug to a certain patient who, in the preceding half year, had not had a similar prescription of the same substance (on fifth ATC level and thereby regardless of dosage, dosage form, pack size and brand) [ 11].
If there was an overlap between two prescriptions of the same drug at the same dose and schedule, we assumed that the first prescription was finished before the second prescription was started rather than assuming a higher amount of drug was taken during the overlap.
The same rule was applied to overlapping prescriptions of the same drug but with different doses and overlapping prescriptions for different drugs within the same drug class (anti-TNF agents, systemic steroids, COXIBs or NSAIDs).
When there was a gap of 7 days or less between two prescriptions of the same drug, or of different drugs within the same drug class (excluding DMARDs), it was assumed that the drug was taken continuously and the gap was filled with the daily dose of the second prescription.
Importantly, they can be viewed side by side with the corresponding distributions for the database as a whole, for other prescriptions of the same drug, and for other prescriptions followed by the same medical event.
These patterns were the same for all three groups of OTC analgesics.> Figures for concomitant use of OTC analgesics and prescriptions of the same group of analgesics were similar for paracetamol and NSAIDs: about 3, 4 and 5% had received prescriptions for the same group of analgesics during the last 4, 6 and 8 weeks, respectively, before HUNT 3 data collection (Table 5).
