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Skeletal formula of 8-chlorotheophylline
Space-filling model of the 8-chlorotheophylline molecule
Clinical data
Routes of
ATC code
  • none
Legal status
Legal status
  • 8-chloro-1,3-dimethyl-7H-purine-2,6-dione
CAS Number
PubChem CID
CompTox Dashboard (EPA)
ECHA InfoCard100.001.446 Edit this at Wikidata
Chemical and physical data
Molar mass214.61 g·mol−1
3D model (JSmol)
  • Cn2c(=O)c1[nH]c(Cl)nc1n(C)c2=O
  • InChI=1S/C7H7ClN4O2/c1-11-4-3(9-6(8)10-4)5(13)12(2)7(11)14/h1-2H3,(H,9,10) checkY
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8-Chlorotheophylline, also known as 1,3-dimethyl-8-chloroxanthine, is a stimulant drug of the xanthine chemical class, with physiological effects similar to caffeine.[1] Its main use is in combination (salt) with diphenhydramine in the antiemetic dimenhydrinate. Diphenhydramine reduces nausea but causes drowsiness, and the stimulant properties of 8-Chlorotheophylline help reduce that side effect.[2]

Despite being classified as a xanthine stimulant, 8-chlorotheophylline can generally not produce any locomotor activity above control in mice and does not appear to cross the blood-brain barrier well.[citation needed]

The 8-chloro modification is not selected for pharmacological properties; instead, it was to raise the acidity of the xanthine amine group enough to form a co-salt with diphenhydramine.[2]

The drug is also sold in combination with promethazine, again as a salt.[3]


  1. ^ Snyder SH, Katims JJ, Annau Z, Bruns RF, Daly JW (May 1981). "Adenosine receptors and behavioral actions of methylxanthines". Proceedings of the National Academy of Sciences of the United States of America. 78 (5): 3260–4. Bibcode:1981PNAS...78.3260S. doi:10.1073/pnas.78.5.3260. PMC 319541. PMID 6265942.
  2. ^ a b 10.1126/science.109.2840.574.a
  3. ^ "The anti-emetic action of both the hydrochloride and the teoclate (8-chlorotheophylline) salts is used for the prevention of nausea in cases of motion sickness and post-operative vomiting."