continuing professional development POTION OR POISON?

providing a Pacific-specific clinical training and support programme for Pacific registrars in The Royal Guarana New Zealand College of General Paullinia cupana, P. sorbilis Practitioners’ (RNZCGP’s) General Practice Education Programme (GPEP Also known as Brazilian cocoa and ‘Zoom’ 1 and 2). This programme is run in partnership with the RNZCGP and David J Woods BSC (Hons), MPharm, MPSNZ, MRPharmS, FNZHPA the Ministry of Health. Our mission is to ‘…increase Pacific workforce in primary care by establishing a work- force training network of Primary Guarana is a berry that grows in Active constituents: Initially Care training organisations’. Venezuela and the northern parts of the active ingredient was called tetra Brazil. The name ‘guarana’ comes from methyl­xantine but it was later discov- At Bader Drive Healthcare (see the Guarani tribe that lives in Brazil. ered that it is actually caffeine. The www.bdhclinicaltrainingsupport. Guarana plays a very important role in guarana plant and berry has one of the co.nz) we deliver both GP services their culture and medical folklore. The highest naturally occurring levels of caf- and community health services to herb is believed to be a magical cure feine at around 7–8%, and there are also Pacific people because we believe in for a range of complaints and a way to traces of theophylline and theobromine. delivering services in a holistic and regain strength. Guarana’s biological Instead of referring to caffeine, many integrated fashion. We have 26 staff in name, Paullinia cupana, was taken from companies and websites market their total delivering services from Mangere the German medical botanist CF Paul- products using the term ‘guaranine’ and Manurewa clinics. The majority lini, who discovered the tribe and the when describing the active ingredient. of our staff is of Pacific ethnicity and plant in the eighteenth century. Other companies clearly label their 90% of our enrolled population are products with the caffeine content, but Pacific. We are accredited by Te Wana Preparations: Guarana can be the impression may be given to consum- and Cornerstone and we are an purchased as capsules, often in combina- ers that there is something additionally RNZCGP accredited teaching practice. tion with ginseng. It is also present in special about guarana. Visit our website for more information stimulant energy drinks that are now about the Bader Drive Clinical Training commonplace, and in some teas and in- Main uses and claims: Amongst a Support Programme. fusions. These drinks often make a point range of possible uses, guarana products of highlighting the inclusion of guarana are claimed to: References in addition to caffeine. • improve concentration, endurance, 1. Gray AM, Phillips VL, Normand C. The costs vitality, immunity, stamina in of nursing turnover: evidence from the Brit- Guaraná Antarctica, which contains its athletes and sexual performance ish National Health Service. Health Policy. namesake, is an iconic and best-selling • slow the effects of ageing 1996;38(2):117–128. 2. Tai T, Bame SI, Robinson CD. Review of nursing soft drink in Brazil due to its distinctive • alleviate migraine, rheumatic disease, turnover research, 1977–1996. Soc Sci Med. and unique taste. The caffeine content diarrhoea, constipation and tension 1998;47(12):1905–1924. 3. shields MA, Ward M. Improving nursing reten- of guarana products is variable but, as a • cure hangovers tion to the National Health Service in England: rough guide, energy drinks on aver- • suppress appetite and facilitate the impact of job satisfaction on intention to quit. J Health Econ. 2001;20(5):677–701. age contain about 90 mg caffeine per weight loss. 4. Jansen P, Sorensen D. Culturally competent health 250 mL which is about the same as a care. NZ Fam Physician. 2002;29(5):306–311. regular cup of coffee, and capsules com- None of the above effects have been 5. statistics New Zealand and Ministry of Pacific Island Affairs. Demographics of New Zealand’s monly contain 20–30 mg caffeine. proven other than those possibly at- Pacific population. Wellington:S tatistics New Zea- land and Ministry of Pacific Island Affairs; 2010. 6. Medical Council of New Zealand. The New Zealand medical workforce in 2009. Wellington: Medical Council of New Zealand; 2010. Available from: http://www.mcnz.org.nz/portals/0/publi- Herbal medicines are a popular health care choice, but few have been tested to cations/workforce_2009.pdf contemporary standards. POTION OR POISON? summarises the evidence for the 7. Ministry of Health. Tupu Ola Moui: The Pacific Health Chart Book 2004. Wellington: Ministry of potential benefits and possible harms of well-known herbal medicines. Health; 2004.

VOLUME 4 • NUMBER 2 • JUNE 2012 JOURNAL OF PRIMARY HEALTH CARE 163 continuing professional development POTION OR POISON?

tributed to the effects of caffeine. There is no good evidence that guarana improves stamina in Summary Message athletes. Some recent trials have suggested that guarana improves fatigue in cancer patients, but The main constituent of guarana is caffeine, again this can be explained by the CNS stimulant with smaller quantities of theophylline and effects of caffeine. theobromine. There is no evidence that the berries or extracts contain anything else that Adverse effects: These are due to the caf- is therapeutically useful. feine content of the product. Excessive intake of guarana can cause nausea, nervousness, tremor, Guarana is associated with many therapeutic irritability, diuresis, gastric irritation and pal- properties, but there is no evidence to support pitations. These effects will be additive to any these other than effects that can be attributed concurrent intake of other sources of caffeine. to caffeine. Many people appear to be doubling up on their Guarana is widely available in herbal products intake of caffeine without realising it and there and energy drinks. Excessive intake can cause are several cases of ‘caffeine overdose’ in the lit- the same effects as too much caffeine. It is not erature that have involved the ingestion of large widely recognised that guarana has a high caf- quantities of guarana-containing energy drinks, feine content and the labelling on some products usually in children. is misleading.

People may experience caffeine withdrawal Although not specifically studied, guarana would effects if they suddenly reduce or stop a high be expected to exhibit the same range of adverse intake of guarana-containing products. Because effects and drug interactions as those associated of the high caffeine content, guarana products, with caffeine. for example energy drinks, are best avoided in pregnancy. References (further reading) Drug interactions: No specific drug inter- 1. Mason P. Guarana in dietary supplements. Pharmaceutical actions have been attributed to guarana, but due Press; 2011. 2. Higgins JP, et al. Energy beverages; content and safety. Mayo the caffeine content, the following interactions Clin Proc. 2010;85(11):1033–41. associated with caffeine appear possible: • Increased plasma clozapine levels—caffeine inhibits the metabolism of clozapine • Decreased plasma lithium levels—caffeine ap- pears to increase the renal excretion of lithium • Additive effects with therapeutic in- take of theophylline or aminophylline • Antagonism of anxiolytic and hypnotic agents • Increased blood pressure with pseudo­ ephedrine and similar drugs J PRIM HEALTH CARE • Reduced effect of antihypertensive agents. 2012;4(2):163–164.

CORRESPONDENCE TO: David Woods School of Pharmacy, University of Otago, PO Box 56, Dunedin 9054, New Zealand [email protected]

164 VOLUME 4 • NUMBER 2 • JUNE 2012 JOURNAL OF PRIMARY HEALTH CARE