It is very common for psychiatric patients, especially those diagnosed with schizophrenia, to be prescribed two or more psychiatric medications at once, and this confers significant health risks from rarely studied drug interactions, according to Turkish University School of Medicine researchers publishing in the Bulletin of Clinical Psychopharmacology. The researchers stated that theirs was the first such study to look specifically at the dangers of psychiatric drug interactions “in real life conditions.”
The researchers study sample consisted of 240 patients with a schizophrenia spectrum disorder. They found that over 70% (172) of them were taking two or more psychiatric medications, and they analyzed the risks of interactions based on the specific drug combinations occurring in all of these individual cases. They found that 87.8% of the interaction risks were moderate, and approximately one quarter of the patients were using medications with a major risk of interactions.
The found that 38.6% of the patients were at moderate risk for increases in anticholinergic side effects, such as dry mouth, bowel obstruction, blurred vision, impaired concentration, attention deficit, and memory impairment. Nearly a quarter were at higher risk of central nervous system and respiratory depression. And nearly 60% were at higher risk of heart problems due to QT interval prolongation. Other cardiovascular, blood drug level and neurotoxicity risks were also identified.
“As far as we know, no study has been done to evaluate the drug–drug interactions that patients with schizophrenia spectrum diseases experience in daily clinical practice, in real life conditions,” wrote the researchers.
“The present study reports that an important percentage of patients are exposed to drug–drug interactions with ever-increasing use of multiple medications in the schizophrenia spectrum of diseases, and among these interactions, most major risks were cardiovascular risks, especially QT prolongation,” concluded the researchers. “Prospective studies with larger numbers of patients are needed in this area.”
(Abstract) (Full text) Risk of Psychotropic Drug Interactions in Real World Settings: a Pilot Study in Patients with Schizophrenia and Schizoaffective Disorder. Sengul, MCB et al. Bulletin of Clinical Psychopharmacology. 2014. Volume: 24, Issue: 3. doi: 10.5455/bcp.20140311041445)