Can i take two naproxen 375mg at once for a toothache ?

No: The maximum effective dose is 550mg. Cutting a 375mg pill in half and taking a 375mg tab would give you a dose of 560mg.

Probably ok: Naproxen sodium is dosed at 500mg initially and then can be repeated every 12 hours as needed for pain control. Don't exceed the manufacture label of dosing because of potential side effects. Trial 375mg then repeat in 8-12 hours if needed for your toothache.

Maximum Dosage: Max dosage: 500 mg PO initially, then 250 mg PO q6-8hr or 500 mg PO q12hr PRN; not to exceed 1250 mg/day naproxen base on day 1; subsequent daily doses should not exceed 1000 mg naproxen base Extended release: 750-1000 mg PO qDay; may temporarily increase to 1500 mg/day if tolerated well and clinically indicated