Clinical data
ATC code
  • 2-[di(phenyl)methoxy]-N,N-dimethylethanamine; 2-(1,3-dimethyl-2,6-dioxopurin-7-yl)acetic acid
CAS Number
Chemical and physical data
Molar mass493.564 g·mol−1
3D model (JSmol)
  • O=C2N(c1ncn(c1C(=O)N2C)CC(=O)O)C.O(CCN(C)C)C(c1ccccc1)c2ccccc2
  • InChI=1S/C17H21NO.C9H10N4O4/c1-18(2)13-14-19-17(15-9-5-3-6-10-15)16-11-7-4-8-12-16;1-11-7-6(8(16)12(2)9(11)17)13(4-10-7)3-5(14)15/h3-12,17H,13-14H2,1-2H3;4H,3H2,1-2H3,(H,14,15)

Etanautine, also known as diphenhydramine monoacefyllinate, is an anticholinergic used as an antiparkinsonian agent. It is a 1:1 salt of diphenhydramine with acefylline, similar to the diphenhydramine/8-chlorotheophylline combination product dimenhydrinate.[1]

As with dimenhydrinate, the stimulant effect of the etanautine counteracts the sedative effect from the diphenhydramine, resulting in an improved therapeutic profile.[2]

The 1:2 salt diphenhydramine diacefylline (with two molecules of acefylline to each molecule of diphenhydramine) is also used in medicine, under the brand name Nautamine.[1][3]


  1. ^ a b Sicari V, Zabbo CP (2022). "Diphenhydramine". StatPearls. Treasure Island (FL): StatPearls Publishing. PMID 30252266. Retrieved 2022-11-02.
  2. ^ Gonzalez F (August 21, 2009). "Diphenhydramine may be useful as a palliative treatment for patients dying with Parkinson's disease and tremors: a case report and discussion". The American Journal of Hospice & Palliative Care. 26 (6): 474–475. doi:10.1177/1049909109338937. PMID 19700649. S2CID 206633832.
  3. ^ "Diphenhydramine Dosage Guide + Max Dose, Adjustments". Retrieved 2022-11-02.