Guarana: Adverse Reactions. Interactions. Pregnancy Use. Practice Points

Toxicity Animal tests have shown that high doses of 1000-2000 mg/kg (intraperitoneal and oral) do not induce significant alterations in parameters for toxicological screening, suggesting an absence of toxicity. Adverse Reactions Due to a lack of clinical studies testing guarana as a stand-alone treatment, it is difficult to determine what adverse reactions may exist. Based on caffeine content, the following adverse effects may theoretically occur at high doses: agitation, tremor, anxiety, restlessness, headache, seizures, tachycardia and premature ventricular contractions, diarrhea, gastrointestinal cramping, nausea and vomiting and diuresis. Significant Interactions Controlled studies are not available, therefore interactions are theoretical and based on evidence of pharmacological activity with uncertain clinical significance. CNS STIMULANTS Additive stimulant activity is theoretically possible — use with caution. CNS SEDATIVES Antagonistic effects are theoretically possible due to the herb’s CNS stimulant activity. However, one in vivo study found no interaction with pentobarbital. Observe patients taking this combination. DIURETICS Additive diuresis effects are theoretically possible — use this Read more […]

Guarana: Uses. Dosage

Clinical Use ALERTNESS Although clinical studies using guarana are not available, anecdotal evidence has suggested that it may produce similar effects to caffeine on subjective feelings of wellbeing, energy, motivation and self-confidence. Guarana may exert a mild antidepressant effect as demonstrated in forced-swimming and open field tests in mice ENHANCED COGNITIVE FUNCTION AND ALERTNESS Two recent double-blind studies have confirmed that guarana has significant effects on cognitive function and provide evidence that these effects are not just mediated by the herb’s caffeine content. One double-blind, placebo-controlled study assessed the effects of four different doses of guarana (37.5, 75, 150 and 300 mg) in 22 subjects. Cognitive performance and mood were assessed at baseline and again 1, 3 and 6 hours after each dose using the Cognitive Drug Research computerised assessment battery, serial subtraction tasks, a sentence verification task and visual analogue mood scales. All doses improved picture and word recognition, results on the Bond-Lader visual analogue scales and caffeine research visual analogue scales showing improvements in alertness and reduced ratings of headache. The two lower doses produced Read more […]

Guarana: Background. Actions

Historical Note Guarana has been used bythe Amazonian Indians of South America for centuries to enhance energy levels, suppress appetite, increase libido and protect them from malaria. More recently, hot guarana beverages have been adopted bythe greater population as a tonic to enhance wellbeing, in much the same way coffee is drunk in Australia. Common Name Guarana Other Names Brazilian cocoa, guarana gum, guarana paste, quarana, quarane, uabano, uaranzeiro, zoom Botanical Name / Family Paullinia cupana (family Sapindaceae) Plant Part Used Seeds Chemical Components Guarana seeds are a rich source of caffeine, containing 3-6% on a dry weight basis. Other major compounds include theobromine, theophylline, tannins, resins, protein, fat and saponins. Main Actions A review of the scientific literature reveals that guarana itself has only recently been the subject of clinical studies. As such, studies pertaining to caffeine are sometimes used to explain the herb’s action, an approach that presupposes the other constituents are either inactive or of such weak effect they need not be recognised. Although this approach is convenient and provides us with some understanding of the herb’s pharmacological effects, Read more […]