Camellia sinensis

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Related to Camelia sinensis: Camellia japonica

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.

green tea

(green tee) ,

Camellia sinensis

(trade name)

Classification

Therapeutic: central nervous system stimulants
Bladder, esophageal, ovarian and pancreatic cancer risk reduction, mental alertness, hypotension, cervical dysplasia associated with human papillomavirus infection, hyperlipidemia, weight loss, protection of the skin from sun damage, genital warts, dental caries, Parkinson's disease

Action

Caffeine in green tea stimulates the CNS and cardiovascular system through adenosine receptor blockade and phosphodiesterase inhibition.

Therapeutic effects

Improved cognitive performance and mental alertness.

Pharmacokinetics

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

Time/action profile

ROUTEONSETPEAKDURATION
POUnknownUnknownUnknown

Contraindications/Precautions

Contraindicated in: Allergy/hypersensitivity; Pregnancy and lactation (doses >200 mg/day due to caffeine content ).
Use Cautiously in: Patients with caffeine sensitivity. Long term use of doses >250 mg/day may produce tolerance, psychological dependence, tachyarrhythmias, and sleep disturbances; Iron deficiency anemia (may worsen); Diabetes (may impair glucose control); Cardiac conditions (may induce arrhythmias in sensitive individuals); Bleeding disorders.

Adverse Reactions/Side Effects

Cardiovascular

  • arrhythmia
  • tachycardia

Central nervous system

  • agitation
  • dizziness
  • excitement
  • insomnia
  • tremors

Gastrointestinal

  • nausea
  • vomiting
  • diarrhea
  • hepatotoxicity
  • abdominal pain

Fluid and Electrolyte

  • hypokalemia

Endocrinologic

  • hyperglycemia

Hematologic

  • prolonged bleeding time

Interactions

Green tea may ↓ effects of adenosine.↑ risk of bleeding with anticoagulants or antiplatelet agents.↑ effects of CNS stimulants.May impair glucose control from antidiabetic agents.abrupt withdrawal can ↑ lithium levels.May ↓ dipyridamole —induced vasodilation.verapamil can ↑ caffeine concentrations by 25%.additive effects with methylxanthines.↑ risk of adverse cardiovascular effects with bitter orange.↑ risk of hepatotoxicity with hepatotoxic herbs or supplements.↑ risk of seizures, hypertension or stroke with ephedra and creatine.
Oral (Adults) Range: 1–10 cups/day. One cup provides approximately 60 mg of caffeine.

Availability

Tea leaves:

Nursing implications

Nursing assessment

  • Monitor BP and heart rate periodically during therapy.
  • Lab Test Considerations: Monitor serum glucose, homocysteine and uric acid levels periodically during therapy.
    • Monitor liver and kidney function periodically during therapy.

Potential Nursing Diagnoses

Impaired memory (Indications)

Implementation

  • May be taken as tea or as an extract in capsules.

Patient/Family Teaching

  • Advise women who may be pregnant or who are breastfeeding to limit green tea due to the caffeine content.

Evaluation/Desired Outcomes

  • Improvement in memory.

Camellia sinensis,

n See green tea.