| 释义 |
black tea
black tea n. A dark tea prepared from fresh tea leaves that have been oxidized before being dried. black′ tea′
n. tea allowed to wither and ferment before being heated and dried. [1780–90] Thesaurus| Noun | 1. |  black tea - fermented tea leaves tea leaf, tea - dried leaves of the tea shrub; used to make tea; "the store shelves held many different kinds of tea"; "they threw the tea into Boston harbor"congou, congou tea, English breakfast tea, congo - black tea grown in ChinaDarjeeling - a fine variety of black tea grown in northern Indiaorange pekoe, pekoe - a superior grade of black tea; grown in India and Sri Lanka and Javasoochong, souchong - a fine quality of black tea native to China |
EncyclopediaSeecamellia sinensisblack tea
black tea (blak tee) blacktea, Camellia sinensis (trade name), English tea (trade name), Theaflavin (trade name) Classification Therapeutic: central nervous system stimulants
Mental alertness HeadacheWeight lossMyocardial infarction and atherosclerosis preventionAction 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.Therapeutic effectsCNS stimulation.Diuresis.Elevated heart rate and BP.PharmacokineticsAbsorption: Unknown.Distribution: Unknown.Metabolism and Excretion: Unknown.Half-life: Unknown.Time/action profile | ROUTE | ONSET | PEAK | DURATION |
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| PO | unknown | unknown | unknown |
Contraindications/PrecautionsContraindicated 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 EffectsCardiovascular- arrhythmia
- hypertension
- tachycardia
Central nervous systemDermatologicEndocrinologicFluid and ElectrolyteGastrointestinal- constipation
- increased stomach acid
Hematologic- iron deficiency
- microcytic anemia
Genitourinary- diuresis
- increased urine sodium, potassium, and calcium levels
Musculoskeletal- 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.AvailabilityTea leaves: OTCNursing implicationsNursing assessment- 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)
ImplementationPatient/Family Teaching- Advise patient that chronic use of black tea may be habit-forming. Abrupt discontinuation may lead to withdrawal symptoms; decrease gradually.
Evaluation/Desired Outcomes- Increased mental alertness.
- Increased urine output.
- Decrease in headache pain.
black teaTea made from leaves that have been fermented before they are dried.See also: teablack tea
Related to black tea: Oolong teaWords related to black teanoun fermented tea leavesRelated Words- tea leaf
- tea
- congou
- congou tea
- English breakfast tea
- congo
- Darjeeling
- orange pekoe
- pekoe
- soochong
- souchong
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