title: Concomitant use of two or more antipsychotic drugs is common in Sweden.
abstract: OBJECTIVE
  To assess the prevalence of concomitant use of two or more antipsychotic drugs and other psychotropic drugs in the Swedish population.
  
  
  METHODS
  Data for this observational cohort study were collected from the Swedish Prescribed Drug Register including all dispensed drugs to the entire Swedish population (9.4 million inhabitants). We identified all individuals with at least one dispensed prescription of antipsychotic drug during January to June 2008. After 12 months, a second exposure period was chosen. Individuals who were dispensed two or more antipsychotic drugs in both periods were considered long-time users of antipsychotic polypharmacy.
  
  
  RESULTS
  In 2008, 1.5% of the Swedish population was dispensed antipsychotic drugs, the majority (75%) using only one antipsychotic drug. Out of individuals who were dispensed 2 or more antipsychotic drugs during the first period, 62% also was also dispensed at least 2 antipsychotic drugs during the second period. A total of 665 different unique combinations were used in 2008. Individuals prescribed two or more antipsychotic drugs during both periods were more often dispensed anxiolytics and sedatives than those who were dispensed only one antipsychotic drug. Elderly were dispensed antipsychotic drugs much more often than younger persons.
  
  
  CONCLUSIONS
  In Sweden, 25% of patients dispensed antipsychotic drugs receive a combination of two or more antipsychotic drugs. Individuals who are dispensed antipsychotic polypharmacy are more often dispensed anxiolytics and sedatives than those prescribed only one antipsychotic drug. Long-term observational studies are needed to assess the efficacy and safety of such combinations.
authors: Division of Clinical Pharmacology, Department of Laboratory Medicine, Karolinska Institute at Karolinska University Hospital, Huddinge, C1:68, SE-141 86 Stockholm, Sweden.
authors: Annica
authors: A
authors: Bergendal
authors: National Board of Health and Welfare, SE-106 30 Stockholm, Sweden.
authors: Helena
authors: H
authors: Schiöler
authors: Division of Clinical Pharmacology, Department of Laboratory Medicine, Karolinska Institutet at Karolinska University Hospital Huddinge, C1:68, SE-141 86 Stockholm Sweden and Stockholm County Council, Box 6909, SE-102 39 Stockholm, Sweden.
authors: Björn
authors: B
authors: Wettermark
authors: Department of Neurobiology, Care sciences and Society, Karolinska Institutet, SLSO, Psykiatri Södra Stockholm, Box 5040, SE-121 05 Johanneshov, Sweden.
authors: Karin Sparring
authors: KS
authors: Björkstén
keywords: antipsychotic agents; drug polytherapy; drug utilization; polypharmacy; psychotic disorders; schizophrenia