Fasting plasma caffeine concentrations, plasma levels of catecholamines and plasma renin activity were measured in patients with cirrhosis and control patients without hepatic dysfunction. A careful dietary history showed no significant difference in caffeine consumption (mean f S.E.) among 46 cirrhotics (86 f 7 mg per day) vs. 34 control patients (91 f 8 mg per day). Fasting plasma caffeine concentrations, however, were significantly higher (7.68 f 1.42 pg per ml) in cirrhotics than in controls (1.01 f 0.20 pg per ml) (p < 0.01). Fasting plasma caffeine concentrations in cirrhotics varied significantly with Child's criteria, namely Child's A patients (2.06 f 0.38 pg per ml); Child's B patients (6.92 f 1.86 pg per ml), and Child's C patients (17.70 f 3.65 pg per ml) (p < 0.001). In 44 cirrhotics, fasting plasma caffeine concentrations were compared with plasma levels of catecholamines and plasma renin activity. Plasma epinephrine concentrations were normal; however, plasma norepinephrine concentrations were increased in six cirrhotics, and plasma renin activities were increased in 28 cirrhotics. After a 3-day caffeine abstinence, plasma caffeine concentration and renin activity were significantly decreased (p < 0.01), and high plasma norepinephrine levels were also decreased in 12 cirrhotics. Plasma caffeine concentration, renin activity and norepinephrine level did not change in a control group of cirrhotics who continued to receive caffeine for 3 days (n = 6). After abstinence from caffeine, the decrease of fasting plasma caffeine concentration correlated well with the decrease of plasma renin activity (r = +0.746, p < 0.01). These results suggest that high levels of plasma renin activity and norepinephrine in cirrhosis are in part related to habitual intake of beverages with caffeine.
Caffeine is present in coffee, tea, cocoa, cola-type drinks and Japanese tea and is a widely used and socially acceptable drug. Concern has been expressed in recent years regarding the potential of caffeine-containing products to produce ill health (1, 2).
Caffeine (1,3,7-trimethylxanthine) is primarily biotransformed in the liver by microsomal drug-metabolizing enzymes and excreted in urine as methylxanthines