title: Dynamic view on affordability of fixed-dose combination antihypertensive drug therapy.
abstract: BACKGROUND
  The use of fixed-dose combinations (FDCs) has been increasing since the Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure recommended using ≥2 drugs as the first-line drug therapy for patients with stage 2 hypertension. FDCs simplify the drug therapy regimen and reportedly lower the drug therapy cost compared with the free combination (FC) of 2 single-agent drugs. This study hypothesized that the affordability of FDCs over FCs would change over time depending on the availability of generic single-agent drugs.
  
  
  METHODS
  This study used the 2009 Medical Expenditure Panel Survey. Antihypertensive drugs were identified based on the Food and Drug Administration national drug directory. Based on the 2 databases, regression models were run to predict average monthly drug cost as well as out-of-pocket cost for each prescription along with their 95% confidence intervals (CIs).
  
  
  RESULTS
  Overall, FDCs (n = 26) had average monthly drug costs similar to respective FCs when FCs were not generically available. However, when FCs were generically available, FDCs (n = 11) had average drugs costs much higher than their respective FCs. For example, Lotrel as an FDC had an average monthly drug cost of $115.97 (95% CI = $96.59-$135.36), whereas its counterpart FC had an average monthly drug cost of $21.00 (95% CI = $18.23-$23.79).
  
  
  CONCLUSIONS
  The cost advantage of FDCs over FCs was reversed when FCs were generically available. The finding of this study informs patients, health-care providers, and drug plans of the importance of making dynamic decisions on preferred drug therapy options depending on the availability of generic drugs.
authors.affiliation: College of Pharmacy, University of Tennessee Health Science Center, Memphis, Tennessee, USA. shhong@uthsc.edu
authors.forename: Song Hee
authors.initials: SH
authors.lastname: Hong
authors.forename: Junling
authors.initials: J
authors.lastname: Wang
authors.forename: Jun
authors.initials: J
authors.lastname: Tang
mesh_terms: D000959:Antihypertensive Agents / Q000008:administration & dosage / Q000191:economics* / Q000627:therapeutic use; D004305:Dose-Response Relationship, Drug; D016527:Drug Costs / Q000639:trends*; D004359:Drug Therapy, Combination; D016568:Drugs, Generic / Q000008:administration & dosage / Q000191:economics* / Q000627:therapeutic use; D005500:Follow-Up Studies; D006801:Humans; D006973:Hypertension / Q000188:drug therapy* / Q000191:economics / Q000453:epidemiology; D009017:Morbidity / Q000639:trends; D012042:Registries; D012189:Retrospective Studies; D013714:Tennessee / Q000453:epidemiology
chemical_list: D000959:Antihypertensive Agents; D016568:Drugs, Generic
keywords: access to drug therapy prescription drug costs; antihypertensive drug therapy; blood pressure; fixed-dose combinations; hypertension.