PORPHYRIA FACTS: NUTRITION - CAFFEINE
Caffeine intake is important as its ingestion may result in therapeutic doses of
theophylline drugs reaching toxic ranges, as both are metabolised by the
xanthine oxidase pathway.
Caffeine ingestion can occur in a variety of ways.
Chocolate and cocoa contain not only caffeine but theobromine which is
metabolised to caffeine prior to complete metabolism.
Chronic, high caffeine intake, or toxicity, can result in headache, rhinorrhoea,
nausea, anxiety, restlessness, irritability, dry mouth, tinnitus, palpitations,
arrthythmius, tachypnoea, increased blood pressure, diuresis, sleep disruptions,
gastrointestinal disturbances, and a variety of other symptoms.
Deaths related to caffeine are uncommon, an individual would need to consume
approximately 75 cups of coffee or 200 colas.
Caffeine has also been reported to cause urticaria in susceptible individuals.
Caffeine crosses into breast milk.
Clearance is decreased by liver disease such as the hepatic porphyrias.
Clearance is increased by smoking.
Sources of Caffeine
SOURCE UNIT CAFFEINE (mg)
100 - 150
85 - 100
Tea (2 mg threobromine)
60 - 75
6 - 42
40 - 60
100 - 200
30 - 66
Vitamin preparations and other tonics.
Sodium salicylate and aspirin disease.
1980; 35: 155-156.