Sedation with non sedating antihistamines
After three, six, or 12 months, “green form” questionnaires are sent to the general practitioners who wrote the original prescriptions.
These questionnaires seek to determine any event experienced by patients while they were taking the drug and for a period afterwards.
They act on histamine receptors in the brain and spinal cord and in the rest of the body (called the periphery).
Second generation antihistamines were developed in the 1980s and are much less sedating than first-generation antihistamines.
The methods of prescription-event monitoring have been previously described in detail.5 In brief, the general practitioner writes a prescription which the patient takes to the pharmacist.
The pharmacist sends all these prescriptions to the Prescription Pricing Authority, which under conditions of full confidentiality, provides electronic copies of the exposure data to the Drug Safety Research Unit.
Incidence densities were calculated for all of the events reported, to give an indication of which events were reported significantly more frequently in the first month of exposure.
We calculated non-adjusted and age and sex adjusted odds ratios for drowsiness or sedation for fexofenadine, cetirizine, and acrivastine using loratadine as baseline.