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#117 Generic Versus Brand Name: The other drug war

Is there any benefit to prescribing brand name medications versus generic brands?

Based on the best available evidence, generic medications are bioequivalent and produce similar clinical outcomes to brand name medications. 

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  • Regulators require 90% confidence intervals (CI) for the maximum peak concentration (Cmax) and total drug exposure over time (AUC) of generic drug be within limits of 0.80-1.25. 
    • This means the absolute differences in bioequivalence must be ~5-7%. 
  • Between 1996-2007, 2070 single-dose bioequivalence studies showed the average difference in Cmax and AUC was 4.35% and 3.56%, respectively. 
  • 98% of studies showed AUC of generic and innovator products’ differed by <10%. 
  • Generic and brand name levothyroxine have been shown to be bioequivalent.2 
  • One study found that of 42 randomly selected brand-generic drug comparisons, 98% met AUC criteria and 88% met Cmax criteria for bioequivalence.3 
Clinical outcomes (brand name versus generic medications): 
  • Two systematic reviews [38-74 randomized control trials (RCTS)] of cardiovascular medications including anti-hypertensives, statins, anti-platelets, anticoagulants:4,5 
    • Both showed no difference in clinical outcomes. 
    • The largest and most recent SR:5 
      • Composite of soft outcomes (e.g. systolic blood pressure, LDL): no statistical difference. 
      • Major adverse cardiovascular events (MACE) or death (3 RCTs): no statistical difference. 
      • Adverse effects 
        • Mild/moderateno difference. 
        • Serious: no difference. 
  • Systematic review of warfarin:6 
    • Five trials (higher level evidence): No statistically significant difference in INR or dosage changes required. 
    • Six observational studies (lower level evidence): Inconsistent results at higher risk of bias.   
  • Systematic review of clopidogrel (3 studies, mixed design) 7. For RCT datano differences observed for: 
    • MACE: 5% versus 4% generic, no statistical difference. 
    • Bleeding: 2% versus 1%, no statistical difference. 
    • Withdrawal: 4% versus 7%, no statistical difference. 
  • Systematic review of antiepileptic drugs (7 RCT, 204 patients)8 
    • Uncontrolled seizures: no difference.
  • Of 43 editorials on generic medication issues, 23 (53%) expressed a negative view of generic substitution,4 while only 8% of trials found any differences in any outcomes.4 
  • If there were important clinical differences between generic and brand name medicationscompanies would do studies to prove brand name superiority and prevent losing millions of dollars from generic substitution.   
    • In fact, one company tried to suppress data demonstrating equivalence of its product and related generics.9 
  • Brand name and generic medications may contain different inactive components (fillers and binders) and may look different. 

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  • G. Michael Allan MD CCFP
  • James McCormack BSc(Pharm) PharmD
  • John T Chmelicek MD CCFP FAAFP FAWM
  • Samantha Moe PharmD

1. Davit BM, Nwakama PE, Buehler GJ, et al. Ann Pharmacotherapy. 2009; 43:1583-97.

2. Dong BJ, Hauck WW, Gambertoglio JG, et al. JAMA. 1997; 277:1205-13.

3. Hammami MM, De Padua SJS, Hussein R, et al. BMC Pharmacol Tox 2017; 18:78.

4. Kesselheim AS, Misono AS, Lee JL, et al. JAMA. 2008; 300:2514-26.

5. Manzoli L, Flacco ME, Boccia S, et al. Eur J Epidemiol 2016; 31 (4): 351-68.

6. Dentali F, Donadini MP, Clark N, et al. Pharmacotherapy. 2011; 31(4):386-93.

7. Caldeira D, Fernandes RM, Costa J, et al. J Cardiovasc Pharmcol 2013; 61(4): 277-82.

8. Kesselheim AS, Stedman MR, Bubrick EJ, et al. Drugs 2010; 70(5): 605-21.

9. Myths and Facts About Generic Drugs. (accessed June 10, 2014)

Authors have no conflicts to disclose.

Most recent review: 17/01/2020

By: Samantha Moe PharmD


Evidence updated: Addition of four systematic reviews; Bottom Line: No change.

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