1.     Caffeine is able to penetrate the blood brain barrier and directly influence the
        CNS
Lamarine (1994) notes caffeine is able to penetrate the blood brain barrier and directly influence
the CNS. Ochs, Holmes, and Karst (1992) report as a chemical, caffeine is a methylated
xanthine, a powerful central nervous system (CNS) stimulant which can arouse all levels of the
          rain and the skeletal muscles.

2.     4-quinolones inhibit biotransformation of caffeine.
The pharmacokinetics of caffeine, including formation of its major metabolite paraxanthine in plasma, has been investigated in 12 healthy males (age 20-40 years) alone and during co-administration of the 4-quinolones ofloxacin, norfloxacin, pipemidic acid, ciprofloxacin, and
         enoxacin; ciprofloxacin and enoxacin were given in 3 different dose levels. The naphthyridine
         derivative enoxacin and the pyrido-pyrimidine derivative pipemidic acid had caused marked
         inhibition of caffeine and paraxanthine metabolism

3.     Ciprofloxacin-caffeine: a drug interaction established using in vivo and in vitro
        investigations.
The inhibitory effects of ciprofloxacin and other quinolone derivatives on the hepatic cytochrome P450-dependent metabolism of caffeine have been investigated in humans. In vivo studies involved an intraindividual comparison of the single-dose kinetics of caffeine before and during quinolone
          administration in 12 healthy men.