black tea(redirected from English Tea)
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Related to English Tea: afternoon tea
black tea(blak tee) ,
Camellia sinensis(trade name),
English tea(trade name),
Mental alertness HeadacheWeight lossMyocardial infarction and atherosclerosis prevention
ClassificationTherapeutic: central nervous system stimulants
Black tea contains caffeine (2–4%) a methylxanthine that stimulates the CNS through adenosine receptor blockade and phosphodiesterase inhibition, relaxes smooth muscle in the airways, stimulates the heart and has diuretic effects. Theaflavins and tannins present in black tea are responsible for antioxidant properties.
Elevated heart rate and BP.
Metabolism and Excretion: Unknown.
Contraindicated in: Allergy or hypersensitivity to caffeine or tannin; Obstetric: Pregnancy and lactation (in high doses due to caffeine content).
Use Cautiously in: Cardiac arrhythmias; Diabetes; Peptic ulcer disease; Osteoporosis (caffeine increases urinary calcium excretion); Iron deficiency anemia (may worsen); Pediatric: Safety and efficacy has not been established in children.
Adverse Reactions/Side Effects
Central nervous system
Fluid and Electrolyte
- increased stomach acid
- iron deficiency
- microcytic anemia
- increased urine sodium, potassium, and calcium levels
- rhabdomyolysis (high doses)
InteractionsCimetidine, disulfiram, fluvoxamine, phenylpropanolamine, fluoroquinolones, and estrogens can ↓ caffeine clearance and ↑ adverse effects. Caffeine can inhibit dipyridamole -induced vasodilation.Abrupt withdrawal of caffeine can ↑ lithium levels.Additive stimulatory effects with CNS stimulants.Caffeine can ↑ theophylline levels.May ↑ heart rate and BP when used with bitter orange.May ↑ stimulatory effects when taken with ephedra and green tea.
Oral (Adults) Heart disease prevention—1–4 cups daily; Headache/mental performance—1–5 cups daily. One cup of black tea contains approximately 50 mg caffeine. A maximum of 8 cups/day has been suggested.
Tea leaves: OTC
- Assess BP and heart rate periodically in patients at risk for cardiovascular side effects.
- Lab Test Considerations: Monitor liver and kidney function tests and blood glucose, plasma homocysteine, and uric acid levels periodically in patients with who drink large amounts of black tea.
Potential Nursing DiagnosesAcute pain (Indications)
- Drink tea as desired.
- Advise patient that chronic use of black tea may be habit-forming. Abrupt discontinuation may lead to withdrawal symptoms; decrease gradually.
- Increased mental alertness.
- Increased urine output.
- Decrease in headache pain.
Tea made from leaves that have been fermented before they are dried.
See also: tea