Gardening Blog

Guarana

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Guarana is the dried paste made from the peeled, dried, roasted, and crushed seeds of Paullinia cupana. It contains 3% to 7% caffeine (coffee contains 1 % to 2% caffeine); tannins, which provide its astringent taste; and theophylline and theobromine, which are alkaloids that are similar to caffeine.

Guarana plays an important role in the society of Amazonian Indians. It is often taken during periods of fasting to improve tolerance for dietary restrictions. The extract is believed to provide protection from malaria and dysentery. It was listed as an official drug in the U. S. Pharmacopeia until 1910.

Guarana is available as alcohol containing extracts, capsules, elixirs, syrups, tablets, and teas. It’s also available in various soft drinks, weight loss products, energy drinks, and vitamin supplements. Common trade names include Guarana Plus, Guarana Rush, and Superguarana.

Reported uses

Guarana is used to promote weight loss, enhance athletic performance, protect against malaria and dysentery, and treat headaches, dysmenorrhea, and digestion problems. It’s used as a stimulant similar to coffee or tea, an aphrodisiac, and a tonic to quiet hunger or thirst. It’s also used as a flavoring agent. Guarana is used primarily as a source of caffeine in soft drinks. It stimulates the central nervous system, suppresses the appetite, and inhibits platelet aggregation. It also induces diuresis and relaxes bronchial smooth muscle.

Administration

Dosage is 1 to 2 capsules containing 200 to 800 mg of guarana extract, not to exceed 3 g every day.

Hazards

Adverse reactions associated with guarana include insomnia, irritation, nervousness, anxiety, headache, rapid heart rate, inhibited platelet aggregation, tinnitus, abdominal spasms, vomiting, diuresis, painful urination, and fibrocystic breast disease.

Interaction with adenosine could lead to a decreased antiarrhythmic effect. Anticoagulants and antiplatelet drugs may increase bleeding tendency. Concomitant use with caffeine-containing analgesics or nonprescription drugs such as NoDoz and Vivarin potentiates the effects of caffeine. Use with cimetidine may decrease the clearance of caffeine from the body, increasing its effects. Ciprofloxacin may decrease the elimination of caffeine from the body, increasing its effects. Ephedrine and phenylpropanolamine can increase stimulant effects and may increase blood pressure.

Large amounts of guarana and caffeine can increase the effects of theophylline. Serum potassium must be monitored if guarana is taken regularly by patients also taking guarana. Hypokalemia induced by excessive guarana use may worsen digoxin toxicity. Additive effects may be seen with guarana and green tea, black tea, or mate.

Pregnant and breast-feeding patients and those with cardiac arrhythmias should avoid use. Patients sensitive to caffeine and patients with cardiovascular or renal disease, hyperthyroidism, spasms, and psychic disorders such as panic attacks or anxiety should use with caution.

Safety Risk Guarana use has been associated with seizures and arrhythmias.

Clinical considerations

• High doses may cause caffeine-like adverse effects.
• Advise patient that the caffeine content in guarana is higher than in coffee.
• If patient is sensitive to caffeine, monitor blood pressure and heart rate.
• If patient is taking an anticoagulant or an antiplatelet, monitor PT and INR.
• The first signs of a toxic reaction are dysuria, vomiting, and abdominal spasms.
• Advise patient who is or wants to become pregnant not to use guarana.
• Tell patient that herb may increase blood pressure, cause arrhythmia, and aggravate hiatal hernia, peptic ulcer disease, gastroesophageal reflux disease, and anxiety or depressive disorders.
• Tell patient to notify pharmacist of any herbal or dietary supplement that he’s taking when obtaining a new prescription.
• Advise patient to consult his health care provider before using an herbal preparation because a conventional treatment with proven efficacy may be available.

Research summary

Guarana has been shown to inhibit platelet aggregation. Urine analysis showed alleged psychoactive elements in essential oil from guarana estagole and anethole remain unchanged. A double blind, placebo-controlled study on 45 healthy elderly volunteers didn’t demonstrate any alteration of cognition after long term guarana use. An in vitro study showed guarana to be genotoxic and mutagenetic. The clinical importance of the above findings is unclear. Guarana in cola soda has been reported to significantly increase risk of erosion on dental enamel.