Anticholinergic effects of oral antipsychotic drugs of typicals versus atypicals over medium- and long-term: systematic review and meta-analysis.

BACKGROUND: Anticholinergic side-effects of antipsychotic drugs are common and can potentially impact on quality of life as well as concordance with medication.
OBJECTIVES: To investigate prevalence/incidence rates of anticholinergic side-effects of oral antipsychotic drugs over the medium- and long-term.
METHODS: We included all systematic reviews undertaken by the Cochrane Schizophrenia Group for people who are taking antipsychotic drugs and suffering from schizophrenia or Schizophrenia-like illnesses. The prevalence/ incidence of any anticholinergic side-effects was calculated. Relevant papers from the Cochrane Database were identified in January 2007 and the data was pooled. Side-effect data was grouped into the medium (3-6 months) and long-term ( > 6 months). We calculated simple frequencies, proportions and confidence intervals. We undertook a comparison within the group and generated a Forrest plot of the data.
RESULTS: We identified 177 studies within 54 reviews (N=27328 participants). Anticholinergic side-effects for blurred vision, dry mouth and constipation manifested for antipsychotics ranging from 1 to 40 % over the medium-term and 1 to 41% over long-term respectively. There were no statistical differences beween typicals and atypicals over medium- and long-term.
CONCLUSION: To the best of our knowledge, we have collated the largest amount of data on anticholinergic side-effects for antipsychotics over the medium- and longterm. Anticholinergic side-effects are common over the medium- and long-term. Over the medium- and long-term there were no statistically significant differences between the typicals and atypicals in the main anticholinergic side-effects with one exception. We found that in the long-term, the typical antipsychotics were associated with a significantly higher prevalence of blurred vision.