black tea


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Related to black tea: Oolong tea

black tea

(blak tee) ,

Camellia sinensis

(trade name),

English tea

(trade name),

Theaflavin

(trade name)

Classification

Therapeutic: central nervous system stimulants
Mental alertness HeadacheWeight lossMyocardial infarction and atherosclerosis prevention

Action

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 effects

CNS stimulation.
Diuresis.
Elevated heart rate and BP.

Pharmacokinetics

Absorption: Unknown.
Distribution: Unknown.
Metabolism and Excretion: Unknown.
Half-life: Unknown.

Time/action profile

ROUTEONSETPEAKDURATION
POunknownunknownunknown

Contraindications/Precautions

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

Cardiovascular

  • arrhythmia
  • hypertension
  • tachycardia

Central nervous system

  • insomnia
  • tremor

Dermatologic

  • rash
  • hives

Endocrinologic

  • hyperglycemia

Fluid and Electrolyte

  • hypokalemia
  • hyponatremia

Gastrointestinal

  • constipation
  • increased stomach acid

Hematologic

  • iron deficiency
  • microcytic anemia

Genitourinary

  • diuresis
  • increased urine sodium, potassium, and calcium levels

Musculoskeletal

  • rhabdomyolysis (high doses)

Interactions

Cimetidine, 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.

Availability

Tea leaves: OTC

Nursing implications

Nursing 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 Diagnoses

Acute pain (Indications)

Implementation

  • Drink tea as desired.

Patient/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 tea

Tea made from leaves that have been fermented before they are dried.
See also: tea
References in periodicals archive ?
To assess the mean zone of inhibition of alcoholic & aqueous extract of oolong and black tea leaves on streptococcus mutans (in vitro)
In studies where subjects drank black tea along with their meal, between 79 and 94 percent of the iron in the meal was not absorbed.1 Peppermint tea was similar to black tea in terms of markedly interfering with iron absorption; other herb teas, such as chamomile tea, had less of an effect.
Research studies have found that black tea processed with fresh tea leaves of different tea leaf sources significantly influences the tea quality [7, 8].
The flavour of standard black tea was also found to be "unappealing" to younger people, especially compared to speciality teas which are often thought of as a treat, The telegraph reported.
She had wanted to become a black tea expert, but it was in Europe when she decided she wanted to learn more about Korean tea.
In contrast, average systolic blood pressure in the black tea group actually increased from 118.6 +/ 14.9 mm Hg to 127.3 +/- 8.7 mm Hg.
The new findings show that black tea antioxidants (polyphenols) stimulate the growth of gut bacteria which favour slimness.
(newbyteas.co.uk) PS5.50 for box of 25 bags TETLEY INDULGENCE CHOCOLATE MINT On paper, this black tea infused with dark chocolate and mint, sounds a little sickly - but it's utterly gorgeous and really works.
Grab a cup of black tea, say scientists who have found that the beverage may promote weight loss by encouraging growth of metabolism-boosting bacteria.
Summary: London [UK], Aug 12 (ANI): If you love to consume a glass of red wine or a good black tea or a blueberry cheesecake, then you may have shielded yourself from flu.
This work was undertaken to evaluate the protective effect of aqueous black tea extract and vitamin C against a rat model of oxidative stress induced by treatment with carbofuran, an organocarbamate insecticide.
They are accomplishing this by marketing a line of Kenyan-grown black tea, and ground and whole bean coffee packaged in handcrafted boxes that look equally at home in the gift department as in the tea aisle.