title: Clinically significant drug interactions in younger and older human immunodeficiency virus-positive patients receiving antiretroviral therapy.
abstract: OBJECTIVE
  To characterize clinically significant drug interactions (CSDIs) in younger and older human immunodeficiency virus (HIV)-positive patients who were receiving antiretroviral therapy.
  
  
  METHODS
  Retrospective medical record review.
  
  
  METHODS
  HIV specialty clinic at a Veterans Affairs medical center.
  
  
  METHODS
  A total of 110 younger (age < 50 yrs) and older (age ≥ 50 yrs) HIV-positive patients receiving antiretroviral therapy during 2007.
  
  
  RESULTS
  Demographic, clinical, and prescription drug data were collected. Pharmacokinetic and pharmacodynamic drug interactions were identified, assigned a severity grade, and evaluated for management according to two sources. Interactions with a grade of 2 (monitoring or timing of doses recommended), 3 (therapy modification recommended), or 4 (contraindicated) were considered CSDIs. Among 36 younger and 74 older patients, 763 CSDIs were identified. At least one CSDI was present in 83.3% and 89.2% of younger and older patients, respectively (p=0.56), with most having both antiretroviral and nonantiretroviral CSDIs. Younger and older patients, respectively, had a median of 3 and 5.5 total CSDIs/patient (p=0.09), 2 and 3 antiretroviral CSDIs/patient (p=0.65), and 0.5 and 2.5 nonantiretroviral CSDIs/patient (p=0.04). The proportions of grade 2, 3, and 4 CSDIs were 74.1%, 25.0%, and 0.9%, respectively, in younger patients and 73.1%, 26.1%, and 0.7%, respectively, in older patients (p=0.92). Younger patients had more CSDIs involving antihistamine, erectile dysfunction, and hormone or corticosteroid agents (p<0.01), whereas older patients had more CSDIs involving antihypertensive and antidiabetic agents (p<0.001). Management and outcomes of grades 3 and 4 antiretroviral CSDIs did not differ significantly by age. A list of frequently mismanaged interactions is provided.
  
  
  CONCLUSIONS
  Clinically significant drug interactions were prevalent in younger and older HIV-positive patients receiving antiretroviral therapy, among which nonantiretroviral interactions should not be overlooked. Knowledge of the drug classes frequently involved in CSDIs by age group and types of CSDIs that are commonly mismanaged may help clinicians optimize care for HIV-infected patients.
authors.affiliation: Pharmacy Service, Veterans Affairs Palo Alto Health Care System, Palo Alto, California 94304, USA.
authors.forename: Pannyun
authors.initials: P
authors.lastname: Yiu
authors.forename: Nancy N
authors.initials: NN
authors.lastname: Nguyen
authors.forename: Mark
authors.initials: M
authors.lastname: Holodniy
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D044966:Anti-Retroviral Agents / Q000009:adverse effects* / Q000627:therapeutic use; D002140:California; D004347:Drug Interactions; D057286:Electronic Health Records; D005260:Female; D006679:HIV Seropositivity / Q000150:complications / Q000188:drug therapy*; D006787:Hospitals, Veterans; D006801:Humans; D008297:Male; D008508:Medication Errors / Q000009:adverse effects; D008875:Middle Aged; D010044:Outpatient Clinics, Hospital; D012042:Registries; D012189:Retrospective Studies; D014728:Veterans; D055815:Young Adult
chemical_list: D044966:Anti-Retroviral Agents