Tiered drug formularies

Evidence Rating  
Mixed Evidence
Evidence rating: Mixed Evidence

Strategies with this rating have been tested more than once and results are inconsistent or trend negative; further research is needed to confirm effects.

Health Factors  
Decision Makers

A drug formulary is a list of generic and brand name drugs that are preferred by a health plan based upon their effectiveness and cost-savings. Formularies can have a single tier, where all drugs have the same cost to patients, or multiple tiers, where cost varies. Many formularies are three-tiered: generic drugs have the lowest co-pay or cost sharing (tier one); preferred brand name medications have a higher co-pay or cost sharing (tier two), and non-formulary drugs have the highest co-pay or cost sharing or require prior authorization (tier three). Some pharmacy benefit programs have added additional tiers as health care costs rise1. On the federal health care exchanges, many insurance plans have four prescription drug tiers: generic, preferred brand name, non-preferred brand name, and specialty drugs, with specialty drugs usually subject to significantly higher cost-sharing2

What could this strategy improve?

Expected Benefits

Our evidence rating is based on the likelihood of achieving these outcomes:

  • Reduced cost of prescription drug benefit

  • Increased medication adherence

Potential Benefits

Our evidence rating is not based on these outcomes, but these benefits may also be possible:

  • Increased use of generic prescription drugs

What does the research say about effectiveness? This strategy is rated mixed evidence.

There is mixed evidence about tiered drug formularies’ effects on health care costs and patients’ medication adherence. Studies indicate that using a 3-tiered drug formulary reduces plan providers’ cost to provide a prescription drug benefit3, 4, 5, 6, 7, 8, 9, but also suggest that drug formularies increase patients’ out-of-pocket costs5, 6, 8, 10, 11. Formularies may increase12, 13 or decrease patients’ medication adherence, depending on structure14, 15.  

Compared to plans with fewer tiers, 3-tier formularies increase prescription drug costs for patients5, 6, 8, 11, such that patients may decrease5, 8, 16, 17 or discontinue use of medications in higher tiers7, 18. Additional evidence is needed to determine whether patients are cutting back on drugs treating chronic conditions, switching to a similar drug on a lower formulary tier, or discontinuing use of unnecessary drugs5, 7, 11, 17, 18.

Three-tier formularies increase use of generic drugs5, 6 and preferred brand name medications among plan participants6. Having low or no copayments for generic medications on the first tier13, and moving drugs into a lower tier, may increase medication adherence12. However, introducing a copayment may lead to decreased adherence, even among high-risk patients15. Formulary restrictions such as cost-sharing and prior authorization also appear to reduce medication adherence14.

Integrating formularies in electronic health records (EHRs) with decision support may increase physician prescribing of generics19, 20, but may not significantly increase patients’ medication adherence19.

How could this strategy impact health disparities? This strategy is rated likely to increase disparities.
Implementation Examples

Several states have passed laws aimed at lowering the cost burden of high price prescriptions. New York prohibits the use of specialty tiers, and Delaware prohibits insurers from placing all drugs of a certain type on the specialty tier. Massachusetts, New York, and Vermont limit insurers to three tiers21.

Implementation Resources

OHSU-DERP - Oregon Health & Science University (OHSU). OHSU Health Services: Drug Effectiveness Review Project (DERP).


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1 RWJF-McCarty 2014 - McCarty S, Cusano D. Specialty tier pharmacy benefit designs in commercial insurance policies: Issues and considerations. Princeton: Robert Wood Johnson Foundation (RWJF); 2014.

2 Buttorff 2015 - Buttorff C, Andersen MS, Riggs KR, Alexander GC. Comparing employer-sponsored and federal exchange plans: Wide variations in cost sharing for prescription drugs. Health Affairs. 2015;34(3):467-476.

3 Cochrane-Luiza 2015 - Luiza VL, Chaves LA, Silva RM, et al. Pharmaceutical policies: Effects of cap and co-payment on rational use of medicines (Review). Cochrane Database of Systematic Reviews. 2015;(5):CD007017.

4 Centeno 2013 - Centeno A, Price V, Robinson N, Tomecko GW, Sedam B. Economic impact of ambulatory care formulary restrictions at a large county health system. American Journal of Health-System Pharmacy. 2013;70(14):1238-1243.

5 Gilman 2008 - Gilman BH, Kautter J. Impact of multitiered copayments on the use and cost of prescription drugs among Medicare beneficiaries. Health Services Research. 2008;43(2):478–95.

6 Landon 2007 - Landon BE, Rosenthal MB, Normand S-LT, et al. Incentive formularies and changes in prescription drug spending. American Journal of Managed Care. 2007;13(6 Pt 2):360–9.

7 Gleason 2005 - Gleason PP, Gunderson BW, Gericke KR. Are incentive-based formularies inversely associated with drug utilization in managed care? Annals of Pharmacotherapy. 2005;39(2):339–45.

8 Huskamp 2005 - Huskamp HA, Deverka PA, Epstein AM, et al. Impact of 3-tier formularies on drug treatment of attention-deficit/hyperactivity disorder in children. Archives of General Psychiatry. 2005;62(4):435–41.

9 Lexchin 2002 - Lexchin J. Effects of restrictive formularies in the ambulatory care setting. American Journal of Managed Care. 2002;8(1):69–76.

10 Ogbechie 2015 - Ogbechie OA, Hsu J. Systematic review of benefit designs with differential cost sharing for prescription drugs. American Journal of Managed Care. 2015;21(5):e338-e348.

11 Huskamp 2003 - Huskamp HA, Deverka PA, Epstein AM, et al. The effect of incentive-based formularies on prescription-drug utilization and spending. New England Journal of Medicine. 2003;349(23):2224-32.

12 Chen 2014 - Chen SY, Shah SN, Lee YC, et al. Moving branded statins to lowest copay tier improves patient adherence. Journal of Managed Care & Specialty Pharmacy. 2014;20(1):34-42.

13 Hoadley 2012 - Hoadley JF, Merrell K, Hargrave E, Summer L. In Medicare part D plans, low or zero copays and other features to encourage the use of generic statins work, could save billions. Health Affairs. 2012;31(10):2266–75.

14 Happe 2014 - Happe LE, Clark D, Holliday E, Young T. A systematic literature review assessing the directional impact of managed care formulary restrictions on medication adherence, clinical outcomes, economic outcomes, and health care resource utilization. Journal of Managed Care & Specialty Pharmacy. 2014;20(7):677-684.

15 Doshi 2009 - Doshi JA, Zhu J, Lee BY, Kimmel SE, Volpp KG. Impact of a prescription copayment increase on lipid-lowering medication adherence in veterans. Circulation. 2009;119(3):390–7.

16 Ungar 2008 - Ungar WJ, Kozyrskyj A, Paterson M, Ahmad F. Effect of cost-sharing on use of asthma medication in children. Archives of Pediatrics & Adolescent Medicine. 2008;162(2):104–10.

17 Landsman 2005 - Landsman PB, Yu W, Liu X, Teutsch SM, Berger ML. Impact of 3-tier pharmacy benefit design and increased consumer cost-sharing on drug utilization. American Journal of Managed Care. 2005;11(10):621–8.

18 Nair 2003 - Nair KV, Wolfe P, Valuck RJ, et al. Effects of a 3-tier pharmacy benefit design on the prescription purchasing behavior of individuals with chronic disease. Journal of Managed Care Pharmacy. 2003;9(2):123–33.

19 Pevnick 2014 - Pevnick JM, Li N, Asch SM, Jackevicius CA, Bell DS. Effect of electronic prescribing with formulary decision support on medication tier, copayments, and adherence. BMC Medical Informatics and Decision Making. 2014;14:79.

20 Fischer 2008 - Fischer MA, Vogeli C, Stedman M, et al. Effect of electronic prescribing with formulary decision support on medication use and cost. Archives of Internal Medicine. 2008;168(22):2433–9.

21 CWF-Corlette 2015 - Corlette S, Williams A, Giovannelli J. State efforts to reduce consumers’ cost-sharing for prescription drugs. The Commonwealth Fund Blog. 2015.

Date Last Updated

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