General

Complementary/Alternative Medicine: This monograph describes a natural or herbal product that is not subject to FDA guidelines for medicines. Patients and clinicians are advised to read package labels carefully to ensure safe and efficacious use.

Pronunciation:
blak tee

Trade Name(s)

• Camellia sinensis
• English tea
• Theaflavin

Ther. Class.

central nervous system stimulants

Common Uses

• Mental alertness
• Headache
• Weight loss
• Myocardial 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 Effect(s):

• CNS stimulation.
• Diuresis.
• Elevated heart rate and BP.

Pharmacokinetics

Absorption: Unknown.

Distribution: Unknown.

Metabolism and Excretion: Unknown.

Half-life: Unknown.

TIME/ACTION PROFILE

Contraindication/Precautions

Contraindicated in:

• Allergy or hypersensitivity to caffeine or tannin
• OB:  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)
• Pedi:  Safety and efficacy has not been established in children.

Adverse Reactions/Side Effects

CV: arrhythmia, hypertension, tachycardia

Derm: hives, rash

Endo: hyperglycemia

F and E: hypokalemia, hyponatremia

GI: constipation, increased stomach acid

GU: diuresis, increased urine sodium, potassium, and calcium levels

Hemat: iron deficiency, microcytic anemia

MS: rhabdomyolysis (high doses)

Neuro: insomnia, tremor

* CAPITALS indicate life-threatening.
Underline indicate most frequent.

Interactions

Natural Drug Interaction

•  Cimetidine,  disulfiram,  fluvoxamine,  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.

Natural-Natural:

• May ↑ heart rate and BP when used with  bitter orange .
• May ↑ stimulatory effects when taken with  green tea .

Route/Dosage

PO (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

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.

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.