The prescribing of drugs for case in veterinary medicine in Norway was investigated through a cross‐sectional survey. Of the 8741 prescriptions issued for animals included in this study 22% were for drug use in veterinarians' practices. Drugs from all but one therapeutic group were prescribed for use in animals. On average, 49% of the prescriptions were for vererinairy prepirations, 43% were for human preparations, and 8% were for formulations prepared by pharmacies. Of prescriptions for specific animal species, 27% of the preparations were not approved for the intended animal species. The corresponding figures for prescriptions of veterinary and human preparations were 7% and 41%, respectively. Of prescriptions for production animals 17% of the preparations were not approved for the intended animal species, and for pets this figure was 30%.
The choice of antibacterial drugs for the treatment of bacterial diseases in farmed salmonids changed dramatically during the period 1980‐1994. In terms of treatment doses, oxytetracycline chloride was the most frequently prescribed antibacterial drug during the periods 1980‐1983 and 1985‐1986. In 1984, prescriptions changed in favour of furazolidone and trimethoprim/ sulphadiazine (1:5). Oxolinic acid was introduced for use in farmed fish in Norway in 1987, and immediately became the drug of choice, comprising 36% and 50% of the prescribed treatment doses in 1987 and 1988, respectively. In 1989, flumequine was temporarily approved for use in farmed salmonids, and during the period 1989‐1994 antibacterial drug therapy in farmed salmonids acquired the character of a‘mono‐therapy’with the quinolones flumequine and oxolinic acid. This rapid change‐over in the choice of drug may partly be explained by the development of bacterial drug resistance in farmed salmonids, both to oxytetracycline and trimethoprim/sulphadiazine. The prescribing of furazolidone declined to zero during the study period. The morbidity caused by bacterial infections was defined as the number of treatment doses of antibacterial drugs per kg biomass of farmed salmonids per year. It was estimated that during the period 1988‐1995, an average of 39% (mean value) of farmed salmon received, in theory, an antibacterial cure once each year. In comparison, the corresponding figure for the period 1981‐1988 was 60%. However, in 1993 this figure fell to 13%, and declined even further in 1994 to 2.3%. The practice of on‐farm mixing of medicated feed, using prescribed raw materials (pure drug substances) or premix formulations, declined significantly during the period 1992‐1994. This was due to the introduction, in 1992, of new regulations on the prescribing of drugs to farmed fish.
The prescribing of drugs for food‐producing animals in Norway was investigated with special emphasis on written information given about withdrawal times. The study was designed as a cross‐sectional prescription survey. Of 1518 prescriptions for food‐producing animals, it was concluded that 1224 of the prescriptions were for drugs requiring withdrawal times for meat, milk or eggs. Of these 1224 prescriptions, 82.8% were for veterinary preparations, 6.6% were for human preparations and 10.6% were for other drugs. For 20.8% of the prescriptions, information about withdrawal time(s) was missing. For prescriptions for veterinary preparations this figure was 5.9%, and for prescriptions for human preparations and other drugs 95.1% and 90.8%, respectively. For veterinary preparations approved for the intended species, as many as 99.2% gave information about withdrawal times on the drug container label. Lack of information about withdrawal times might give rise to drug residues in food for human consumption and thus pose a potential hazard to human health.
Compliance with Norwegian legal regulations for veterinary prescriptions was investigated and evaluated. The study was designed as a cross‐sectional prescription survey, and the prescriptions were recorded in Dbase III. Of the 6505 written and telephone prescriptions collected only about one in five fulfilled the legal requirements, namely, giving information about the animal species the drug was intended for, indication for the prescribed drug and directions for use. On average 86% contained information about the animal species, while 26% and 80%, respectively, contained information about the indication for the prescribed drug and directions for use. The number of prescriptions on which indication and directions for use were given, was significantly higher for written prescriptions than for telephone prescriptions, and for prescriptions of human preparations compared with prescriptions of veterinary preparations. For pets, the number of prescriptions containing directions for use was significantly higher than for production animals. The proportion of prescriptions for pets giving a statement of the indication was not significantly different from prescriptions for production animals.
