Difenamizole  (Synonyms: Pasalin)

Difenamizole (Pasalin) is an orally active pyrazole non-steroidal anti-inflammatory agent and pain inhibitor, which capable of crossing the blood-brain barrier. Difenamizole inhibits the release of catecholamines by monoaminergic neurons, reduces the concentrations of dopamine metabolites and normetanephrine (NE) in the striatum, and thereby regulates the levels of dopamine and norepinephrine in the brain. Difenamizole is not only antagonized by dopamine in the brain, but also exerts synergistic effects with Oxidopamine (6-OHDA) (HY-B1081/A), Phenoxybenzamine (HY-B0431), Reserpine (HY-N0480), and other agents. Difenamizole inhibits conditioned, emotional and aggressive behaviors in rodents, and can be used in studies of pain and related neurobehaviors^[1][2].

Difenamizole (25-150 mg/kg; p.o.; single dose) alters cerebral catecholamine and metabolite levels in healthy male ddY mice, including dose-dependent increases in dien-+mesencephalic NE and significant decreases in striatal 3-MT and dien-+mesencephalic NM^[1].
Difenamizole (50 mg/kg; p.o.; single dose) significantly reduces striatal 3-MT and HVA concentrations 60 minutes post-administration in healthy male ddY mice^[1].

MedChemExpress (MCE) has not independently confirmed the accuracy of these methods. They are for reference only.

334.42

C₂₀H₂₂N₄O

20170-20-1

O=C(NC1=CC(=NN1C=2C=CC=CC2)C=3C=CC=CC3)C(N(C)C)C

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• [1]. Nabeshima T, et al. Effects of difenamizole on content of catecholamines and metabolites in mouse brain[J]. The Japanese Journal of Pharmacology, 1978, 28(4): 642-646.

  [2]. Saleem BAA, et al.. Design, synthesis, and mechanistic evaluation of novel pyrazole/thiazole chalcone hybrids as dual tubulin polymerization and COX-2 inhibitors with potent antiproliferative activity. RSC advances. 2026 Jun 02;16(33):30052-30069.  [Content Brief]