Diflunisal
NSAID analgesic and anti-inflammatory drug
From Wikipedia, the free encyclopedia
Diflunisal is a salicylic acid derivative with analgesic and anti-inflammatory activity.[4] It was developed by Merck Sharp & Dohme in 1971, after showing promise in a research project studying more potent chemical analogs of aspirin.[5] It was first sold under the brand name Dolobid, by Merck & Co., but generic versions are widely available. It is classed as a nonsteroidal anti-inflammatory drug (NSAID) and is available in 250 mg and 500 mg tablets.
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| Trade names | Dolobid |
| Other names | MK647 |
| AHFS/Drugs.com | Monograph |
| MedlinePlus | a684037 |
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| Routes of administration | By mouth |
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| Bioavailability | 80-90% |
| Protein binding | >99% |
| Metabolism | Liver |
| Elimination half-life | 8 to 12 hours |
| Excretion | Kidney |
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| ECHA InfoCard | 100.040.925 |
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| Formula | C13H8F2O3 |
| Molar mass | 250.201 g·mol−1 |
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Medical uses
Contraindications
- Hypersensitivity to aspirin/NSAID-induced asthma (AERD) or urticaria
- 3rd trimester pregnancy
- Coronary artery bypass surgery (peri-op pain)
Amyloidosis
Both diflunisal[6][7] and several of its analogues[8] have been shown to be inhibitors of transthyretin-related hereditary amyloidosis, a disease which currently has few treatment options. Phase I trials have shown the drug to be well tolerated,[9] with a small Phase II trial (double-blind, placebo-controlled, 130 patients for 2 years) in 2013 showing a reduced rate of disease progression and preserved quality of life.[10]
Side effects
In October 2020, the US Food and Drug Administration (FDA) required the prescribing information to be updated for all nonsteroidal anti-inflammatory medications to describe the risk of kidney problems in unborn babies that result in low amniotic fluid.[11][12] They recommend avoiding NSAIDs in pregnant women at 20 weeks or later in pregnancy.[11][12]
Mechanism of action
Diflunisal acts by inhibiting the production of prostaglandins,[13] hormones which are involved in inflammation and pain. Diflunisal also has an antipyretic effect, but this is not a recommended use of the drug.[14]
It has been found to inhibit p300 and CREB-binding protein (CBP), which are epigenetic regulators that control the levels of proteins that cause inflammation or are involved in cell growth.[15]
Duration of effect
Though diflunisal has an onset time of 1 hour, and maximum analgesia at 2 to 3 hours, the plasma levels of diflunisal will not be steady until repeated doses are taken.[14] The long plasma half-life is a distinctive feature of diflunisal in comparison to similar drugs. To increase the rate at which the diflunisal plasma levels become steady, a loading dose is usually used. It is primarily used to treat symptoms of arthritis,[16] and for acute pain following oral surgery, especially removal of wisdom teeth.[17]
Society and culture
Legal status
In April 2025, the Committee for Medicinal Products for Human Use of the European Medicines Agency adopted a positive opinion, recommending the granting of a marketing authorization for the medicinal product Attrogy, intended for the treatment of hereditary transthyretin-mediated amyloidosis in adults with stage 1 or stage 2 polyneuropathy.[2] The applicant for this medicinal product is Purpose Pharma International AB.[2] Diflunisal was authorized for medical use in the European Union in July 2025.[2][3]
Research
Diflunisal may have some antibacterial activity in vitro against Francisella tularensis live vaccine strain (LVS).[18]
