title: Use of drugs that act on the cytochrome P450 system in the elderly.
abstract: OBJECTIVE
  The objective of this study was to analyze medications that act on the cytochrome P450 (CYP450) enzymatic system and are used daily by non-institutionalized elderly individuals.
  
  
  METHODS
  A cross-sectional population-based study of elderly individuals (> or = 60 years old) was conducted. All continuously used medications with hepatic metabolism via CYP450 that are classified as substrates, inducers or inhibitors were considered. For the analysis, elderly individuals were stratified according to age groups, and hepatic metabolism activity due to daily alcohol consumption and smoking were considered.
  
  
  RESULTS
  Elderly individuals (396 in total: 222 women and 174 men) between 60 and 95 years of age (mean: 72.1) were assessed. Use of drugs that act on CYP450 was identified in 61.6% of the subjects. Drug use was observed among 16.2% of the subjects: three drugs among 9.8% and four or more among 6.3% of the subjects. The metabolic activities of the drugs used were classified as substrates (58.8%), inhibitors (14.9%), and inducers (4.3%). The main drugs used were beta-blockers and statins (as substrates), proton pump inhibitors and fluoxetine (as inhibitors), and prednisone and carbamazepine (as inducers).
  
  
  CONCLUSIONS
  The results demonstrate that the elderly use high levels of medications that act on CYP450, thereby increasing the risk of drug interactions in a group that is already vulnerable to adverse drug effects.
authors.affiliation: Universidade Estadual de Londrina, Londrina, PR, Brazil. marcoscabrera@uol.com.br
authors.forename: Marcos A S
authors.initials: MA
authors.lastname: Cabrera
authors.forename: Renata M
authors.initials: RM
authors.lastname: Dip
authors.forename: Maira O
authors.initials: MO
authors.lastname: Furlan
authors.forename: Sara L
authors.initials: SL
authors.lastname: Rodrigues
mesh_terms: D017677:Age Distribution; D000368:Aged; D000369:Aged, 80 and over; D000428:Alcohol Drinking / Q000009:adverse effects; D000704:Analysis of Variance; D016009:Chi-Square Distribution; D003430:Cross-Sectional Studies; D065607:Cytochrome P-450 Enzyme Inhibitors; D003577:Cytochrome P-450 Enzyme System / Q000187:drug effects* / Q000378:metabolism; D004347:Drug Interactions; D004790:Enzyme Induction / Q000187:drug effects; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005260:Female; D006801:Humans; D008099:Liver / Q000201:enzymology; D008297:Male; D017678:Sex Distribution; D012907:Smoking / Q000009:adverse effects
chemical_list: D065607:Cytochrome P-450 Enzyme Inhibitors; D004791:Enzyme Inhibitors; D003577:Cytochrome P-450 Enzyme System