Phenazopyridine

Phenazopyridine is a competitive SARM1 inhibitor, with IC₅₀ 145 μM. Phenazopyridine is a TRPM8 antagonist. Phenazopyridine has a local anesthetic/analgesic effect. Phenazopyridine is used to relieve painful symptoms of conditions such as cystitis and urethritis. Phenazopyridine can promote neuronal differentiation and can also be used in the study of traumatic brain injury, peripheral neuropathy and neurodegenerative diseases^{[1][2][3][4][5]}. IC50 & Target:EC50: 145 μM (SARM1)^[1].
In Vitro:Phenazopyridine (10-30 μM; 12 h) increases mRNA expression of RPS23RG1 in both human SHSY5Y and mouse N2a cells^[2].
Phenazopyridine (5-50 μM; 2 min) inhibits menthol induced (50 μM) TRPM8 response in a dose-dependent and reversible manner in HEK293 cells with an IC₅₀ of 9.6 μM^[4].
Phenazopyridine hydrochloride(3 μM; 6 weeks) can promote neuronal differentiation in human embryonic stem cells^[5].
In Vivo:Phenazopyridine (15 m/kg; Intracerebroventricularly injection; Once daily for 2 weeks) improves some AD-related cognitive impairment and pathology in Alzheimer's disease (AD) APP/PS1 mice by promoting the expression of Rps23rg1^[2].
Phenazopyridine (0.1-3 mg/kg; i.v.; Single dose) can inhibit mechanosensitive Aδ- fibers, but has no inhibitory effect on C-fibers in Sprague - Dawley rats^[3].