black tea

(redirected from Theaflavin)
Also found in: Dictionary, Thesaurus, Wikipedia.

black tea

(blak tee) ,

Camellia sinensis

(trade name),

English tea

(trade name),


(trade name)


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


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.
Elevated heart rate and BP.


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

Time/action profile



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


  • arrhythmia
  • hypertension
  • tachycardia

Central nervous system

  • insomnia
  • tremor


  • rash
  • hives


  • hyperglycemia

Fluid and Electrolyte

  • hypokalemia
  • hyponatremia


  • constipation
  • increased stomach acid


  • iron deficiency
  • microcytic anemia


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


  • rhabdomyolysis (high doses)


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.


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)


  • 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.
Drug Guide, © 2015 Farlex and Partners

black tea

Tea made from leaves that have been fermented before they are dried.
See also: tea
Medical Dictionary, © 2009 Farlex and Partners
References in periodicals archive ?
Many studies have looked into the benefits theaflavins have on people consuming anywhere from one to six cups of tea a day.
And on the aroma, color and body producing chemicals like theaflavin, thearubigin and theabrown, that are produced by oxidation of polyphenols during the processing of black tea.
Cooke et al., "Breast cancer prevention by green tea catechins and black tea theaflavins in the C3(1) SV40 T, t antigen transgenic mouse model is accompanied by increased apoptosis and a decrease in oxidative DNA adducts," Journal of Agricultural and Food Chemistry, vol.
First, the company is the only one to successfully extract and preserve theaflavins found in tea, which are the active ingredients produced when green tea ferments and changes into black or oolong tea.
ArthroMax[R] with Theaflavins and ApresFlex[R] ArthroMax[R] Advanced with UC-II[R] and
Ramji et al., "Inhibitory effects of black tea theaflavin derivatives on 12-O-tetradecanoylphorbol13-acetate-induced inflammation and arachidonic acid metabolism in mouse ears," Molecular Nutrition and Food Research, vol.
Catechins are the major biochemical constituents present in tea leaves, and they are oxidized to theaflavins (TFs) and thearubigins (TRs) during fermentation [3].
Theaflavins are black tea polyphenols with well-documented tumor-suppressing activity.
In tea, prominent phytochemicals are theaflavin, thearubingins and theabrownin belong to flavanols while flavonols are composed of quercetin, kaempferol and myricetin.
In tea, the major flavonoids that act as antioxidants are epigallocatechin-3-gallate (EGCG), the primary catechin in green tea, and theaflavin, a major component of black tea.