Lecture 16b

Lecture 16b - Affects on other Body Parts: Acts on...

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Caffeine Xanthines
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Caffeine Facts Pharmacokinetics: Route: oral Slow absorption in stomach; most absorbed in small intestine Effect peaks within 30-60 min ½-life ~ 3 hours Metabolized by CYP450 enzymes Excreted through the kidneys Affects on the Brain: All Xanthines have multiple actions complex pattern of effects Primary action: block the activity of adenosine Adenosine receptors throughout the body (brain, heart, blood vessels, kidney, smooth muscle) Brain – binding of adenosine to its receptors sedation Caffeine stimulation by dis-inhibition Decreases blood flow in the brain (1 starbucks = ¼ drop, no tolerance) Dependence & withdrawal – headaches and fatigue (~ 3-7 days)
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Unformatted text preview: Affects on other Body Parts: Acts on cardiovascular centers in the brainstem and directly on the heart Large dose (500 mg) increases BP & HR (10-20 BPM) & can induce arrhythmia No significant effect of small dose in health individuals Caffeine Facts (contd) The Heart: Adenosine receptors in the kidneys caffeine affects these causing affects similar to diuretics - increased urine production Slows release of antidiuretic hormone from the brain The Kidneys: Acids, oils & caffeine in coffee can irritate lining of stomach and cause secretion of acids gastritis The GI Tract: Stimulates RR and causes bronchioldilation by relaxing smooth muscle The Respiratory System:...
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Lecture 16b - Affects on other Body Parts: Acts on...

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