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Sympathomimetic effects of paraxanthine and caffeine in humans
- Source :
- Clinical pharmacology and therapeutics. 58(6)
- Publication Year :
- 1995
-
Abstract
- Caffeine is metabolized extensively (on average 80%) to paraxanthine. With regular caffeine consumption, average serum levels of paraxanthine are two thirds those of caffeine. Both caffeine and paraxanthine competitively and nonselectively inhibit adenosine receptors in vitro. To examine the contribution of paraxanthine to the pharmacologic activity of caffeine, we administered to 12 subjects in a crossover design oral caffeine (2 or 4 mg/kg) versus placebo or oral paraxanthine (same dose as caffeine) versus placebo, each after 3 days of methylxanthine abstinence. Both caffeine and paraxanthine significantly increased diastolic blood pressure, plasma epinephrine levels, and free fatty acids. Caffeine and paraxanthine produced a similar magnitude of response at 4 mg/kg; however, caffeine appeared to produce greater responses than paraxanthine at 2 mg/kg. Caffeine and paraxanthine have similar sympathomimetic actions. The activity of paraxanthine needs to be considered in understanding the clinical pharmacology of caffeine, particularly with chronic, repetitive caffeine consumption.
- Subjects :
- Adult
Male
Epinephrine
Blood Pressure
Pharmacology
chemistry.chemical_compound
Norepinephrine
Pharmacokinetics
Theophylline
Oral administration
Heart Rate
Reference Values
Caffeine
medicine
Humans
Pharmacology (medical)
Paraxanthine
Chemistry
Fatty Acids
Middle Aged
Adenosine receptor
Crossover study
Central Nervous System Stimulants
Female
medicine.drug
Subjects
Details
- ISSN :
- 00099236
- Volume :
- 58
- Issue :
- 6
- Database :
- OpenAIRE
- Journal :
- Clinical pharmacology and therapeutics
- Accession number :
- edsair.doi.dedup.....4e18076236112d2e286c46a34a6ecd77