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  5. Drug Efficacy Study Implementation (DESI)
  1. Enforcement Activities | FDA

Drug Efficacy Study Implementation (DESI)

FDA’s administrative process to consider the effectiveness of drugs that had been approved only for safety between 1938 and 1962 is called the drug efficacy study implementation (DESI).

Congress amended the Federal Food, Drug, and Cosmetic Act in 1962 to require that new drugs be shown effective, as well as safe, to obtain FDA approval. The amendment required FDA to evaluate the effectiveness of the drugs the agency had approved only for safety between 1938, when Congress enacted the FD&C Act requiring new drugs be shown safe prior to marketing, and 1962.

Open DESI Proceedings

A few DESI proceedings remain open without a final decision or resolution. It is the agency’s policy that drugs subject to an open DESI proceeding may remain on the market during the proceedings.


Evaluation Procedure

FDA contracted with the National Academy of Sciences/National Research Council (NAS/NRC) to make an initial evaluation of the effectiveness of more than 3,400 drugs that had been approved only for safety between 1938 and 1962. The agency reviewed and reevaluated the NAS/NRC reports and published its initial findings in Federal Register notices.

DESI covered the drugs reviewed by NAS/NRC, as well as the even larger number of drugs that entered the market—without FDA approval—as identical, related or similar to those covered by safety-only FDA approvals.

Final DESI Determinations

FDA’s final DESI determination classifies a drug as either effective for one or more of its labeled indications or lacking substantial evidence of effectiveness for one or more of its labeled indications. Most DESI proceedings have been closed and FDA’s findings have been published in the Federal Register.

  • If FDA’s final DESI determination classifies the drug as effective for one or more of its labeled indications, the product can be marketed for those indications, provided it is the subject of an application approved by FDA for safety and effectiveness. Medicines with a new drug application (NDA) approved before 1962 only for safety require an approved supplement to the original application if found to be effective under DESI. Drugs marketed as identical, related or similar to a DESI drug that FDA classified as effective require either an approved NDA or abbreviated new drug application (ANDA), as appropriate, to be marketed. After FDA approves the application, the drug’s regulatory status is the same as any other drugs approved by FDA for safety and efficacy and is no longer considered part of DESI.
  • If FDA’s final DESI determination classifies a drug as lacking substantial evidence of effectiveness, the agency will provide notice of an opportunity for a hearing. The agency considers these requests and either grants or denies it. If a hearing request is denied or if no hearing is requested, FDA publishes its final determination in the Federal Register withdrawing FDA approval due to lacking substantial evidence of effectiveness. Drugs classified as lacking substantial evidence of effectiveness and those identical, related or similar to it can no longer be marketed and are subject to enforcement action as unapproved new drugs.

The New Drugs, Reports of Information for Drug Effectiveness Federal Register notice (July 9, 1966) provides historical information.

Open DESI Proceedings and Recent Final Decisions (updated August 2020)

DESI number



Final agency decision

(Part of) DESI 597

Anticholinergic/Barbiturate Combinations (Donnatal)

(formerly 79N-0184)


(Part of) DESI 597

Donnatal Extentabs

(formerly 75N-0223)


(Part of) DESI 1786

Pentaerythritol Tetranitrate (PETN)


(formerly FDA-1987-N-0054;
formerly 87N-0262)

85 Federal Register 42002 (July 13, 2020)


(Part of) DESI 1786

Oral Nitroglycerin, Extended Release

(formerly 75N-0240)


DESI 5378


(formerly 79N-0190)


DESI 6403

Peripheral Vasodilators, Vasodilan (Isoxsuprine)

(formerly 84N-0167)

85 Federal Register 42882 (July 15, 2020)


DESI 7661

Estrogen-Androgen Fixed-Combination Drug Products; Syntest D.S. and Syntest H.S. tablets

(formerly 76N-0377)


DESI 7663

Potassium Aminobenzoate Oral Preparations; Potaba

(formerly 77N-0187)


DESI 8076

Benzocaine, Butyl Aminobenzoate (Butamben), and Tetracaine Hydrochloride Fixed Combination Drug Product; Cetacaine

(formerly 75N-0203)


DESI 10367

Iodochlorhydroxyquin and Hydrocortisone, Vioform HC

(formerly 80N-0012)

85 Federal Register 42877 (July 15, 2020)


DESI 10837

Oral Prescription Drugs Containing an Anticholinergic or Antispasmodic in Combination with a Sedative. And Single-Entity Antispasmodic Drug Products, in Oral Dosage Form

(formerly 75N-0184)



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