Case study – possible interaction of anxiolytic drugs and a herbal sleep remedy containing Lavender essential oil
This was a story related to me in August 2018, by an aromatherapist friend and her partner who have been using essential oils for many years for many different purposes. The man is in his 60s, and generally a fit and strong man, an ex-Vietnam veteran, who has been taking anxiolytic medication to help him manage his Post Traumatic Stress Disorder.
They decided to trial a herbal sleep remedy with Lavender oil in it that was supposed to help promote restful sleep, and added a couple of capsules to his medication one evening, as he was not sleeping well.
The morning after taking the herbal sleep capsules this is how the man described his experience:
After waking up following voiding of my bowels in bed:
(1) I tried to get out of bed as I felt unclean.
(2) I could not stand up properly and crashed to the floor. I lay on the floor for several minutes, until I could gather my strength and stand up. By this time my partner helped me up and gave me directions to the shower.
(3) When I was wobbly before I crashed to the floor, I vaguely remember vision problems as I could not orientate myself between the bed and the side dresser and I was quite dizzy. I had to confirm where I was by touch. I took a few wobbly steps and crashed to the floor at the end of the bed. I lost all strength to my knees and collapsed. [This is all very embarrassing to me as I consider myself a Rock and a strong man].
I cannot recall my state the next morning, as from memory, I felt quite crook and stayed in bed until early pm that day.
His usual medication regime, most of which are S4 prescription medications, with extensive warnings, is as follows:
Escitalopram; Seroquel; Imovane; Apo-risperidone (full details of dosage in attached PDF, see below).
The capsules contained the following: Lavender essential oil and L-Theanine along with lemon balm, passionflower, and chamomile (dosage not given; preparation not stated for the last three ingredients, whether herbal powder or essential oil).
The list of reference papers given by the capsule company supporting the use of these ingredients is also in the attached PDF, and I’ve found out what the dosage was in each of the papers, so the dosage in the capsules was probably something similar.
The suggested dose for the herbal sleep capsules was 2 capsules a night, which would “deliver the recommended dose” of Lavender essential oil, presumably either 80 mg or 160 mg. This dosage was found to be equivalent to Lorazepam in reducing anxiety if taken over 8 weeks (Woelk & Schläfke, 2010). Linalool, the main constituent in Lavender oil (about 42%) has been shown to potentiate GABAA receptors, producing a similar effect to benzodiazepines in vitro (Milanos, Elsharif, Janzen, Buettner, & Villmann, 2017).
These two papers were what alerted me to the possibility that perhaps the Lavender oil in the capsules may have interacted with the mixture of drugs already in the man’s system, to exacerbate the dizziness side-effects. I don’t know what would have caused the nocturnal voiding of the bowels while he was asleep, however.
I think the event was a drug interaction between the components of the herbal sleeping capsules and the man’s existing medication, and that people taking S4 drugs should take care when taking oral dosages of Lavender essential oil, as there may well be unexpected drug interactions such as the ones reported here.
Bradley, B. F., Brown, S. L., Chu, S., & Lea, R. W. (2009). Effects of orally administered lavender essential oil on responses to anxiety-provoking film clips. Hum Psychopharmacol, 24(4), 319-330. doi:10.1002/hup.1016
Chang, S. M., & Chen, C. H. (2016). Effects of an intervention with drinking chamomile tea on sleep quality and depression in sleep disturbed postnatal women: a randomized controlled trial. J Adv Nurs, 72(2), 306-315. doi:10.1111/jan.12836
Fißler, M., & Quante, A. (2014). A case series on the use of lavendula oil capsules in patients suffering from major depressive disorder and symptoms of psychomotor agitation, insomnia and anxiety. Complement Ther Med, 22(1), 63-69. doi:10.1016/j.ctim.2013.11.008
Higashiyama, A., Htay, H. H., Ozeki, M., Juneja, L. R., & Kapoor, M. P. (2011). Effects of l-theanine on attention and reaction time response. Journal of Functional Foods, 3(3), 171-178. doi:https://doi.org/10.1016/j.jff.2011.03.009
Juneja, L. R., Chu, D.-C., Okubo, T., Nagato, Y., & Yokogoshi, H. (1999). L-theanine—a unique amino acid of green tea and its relaxation effect in humans. Trends in Food Science & Technology, 10(6), 199-204. doi:https://doi.org/10.1016/S0924-2244(99)00044-8
Kakuda, T. (2011). Neuroprotective effects of theanine and its preventive effects on cognitive dysfunction. Pharmacol Res, 64(2), 162-168. doi:10.1016/j.phrs.2011.03.010
Kennedy, D. O., Scholey, A. B., Tildesley, N. T. J., Perry, E. K., & Wesnes, K. A. (2002). Modulation of mood and cognitive performance following acute administration of Melissa officinalis (lemon balm). Pharmacology Biochemistry and Behavior, 72(4), 953-964.
Kimura, K., Ozeki, M., Juneja, L. R., & Ohira, H. (2007). l-Theanine reduces psychological and physiological stress responses. Biological Psychology, 74(1), 39-45. doi:https://doi.org/10.1016/j.biopsycho.2006.06.006
Milanos, S., Elsharif, S. A., Janzen, D., Buettner, A., & Villmann, C. (2017). Metabolic Products of Linalool and Modulation of GABAA Receptors. Front Chem, 5, 46. doi:10.3389/fchem.2017.00046
MIMS/myDoctor. (2017). Medicine Finder. Retrieved from https://www.nps.org.au/medical-info/medicine-finder/
Ngan, A., & Conduit, R. (2011). A double-blind, placebo-controlled investigation of the effects of Passiflora incarnata (passionflower) herbal tea on subjective sleep quality. Phytother Res, 25(8), 1153-1159. doi:10.1002/ptr.3400
Nobre, A. C., Rao, A., & Owen, G. N. (2008). L-theanine, a natural constituent in tea, and its effect on mental state. Asia Pac J Clin Nutr, 17 Suppl 1, 167-168.
Scholey, A., Gibbs, A., Neale, C., Perry, N., Ossoukhova, A., Bilog, V., . . . Buchwald-Werner, S. (2014). Anti-stress effects of lemon balm-containing foods. Nutrients, 6(11), 4805-4821. doi:10.3390/nu6114805
Woelk, H., & Schläfke, S. (2010). A multi-center, double-blind, randomised study of the Lavender oil preparation Silexan in comparison to Lorazepam for generalized anxiety disorder. Phytomedicine, 17(2), 94-99. doi:http://dx.doi.org/10.1016/j.phymed.2009.10.006
By E Joy Bowles, PhD, BSc Hons.
As a scientist, I have mixed feelings about the way scientific research is being used to support the claims for essential oil use. On the one hand, I am delighted that essential oil users are curious about how their oils work, and are keen to seek out more information. On the other hand, I am alarmed that they are happy to settle for summaries of research and claims made in abstracts without going to the source articles or reading the full papers to double-check the claims made.
As an example, two papers have come to my attention recently, both posted on Facebook by well-meaning essential oil enthusiasts.
Valid or invalid: exposure to essential oils for more than 1 hour may be harmful to cardiovascular health?
A report in the European Journal of Preventive Cardiology “The effect of essential oil on heart rate and blood pressure among solus por aqua workers” published in 2014 claims in the abstract “Prolonged exposure for longer than 1 hour to essential oils may be harmful to cardiovascular health among spa workers”. The person posting it on Facebook was alarmed, and wanting to caution their friends about using essential oils safely.
Their trial involved 100 healthy young spa workers inhaling vaporised Bergamot oil over a 2-hour period, and having their blood pressure taken every 15 minutes. The experiment was repeated 3 times, and there were no statistically significant results between the results from each occasion. Initially participants experienced a small decrease in mean systolic and diastolic blood pressure and pulse rate, but in the measurements taken during the second hour of the experiment, they experienced a small increase in means for these measures, compared to baseline. The mean decrease in systolic BP was -2.1 mmHg (at the 45-minute measure), the mean increase was + 2.19 mmHg (at the end of the 2 hours).
However, there was no control group, so there is no way of knowing whether the changes in BP were due to the Bergamot oil, or not. Conceivably, people’s BP could drop just by sitting still for 45 minutes, and could rise again as they got stressed by being bored during the second hour!
In their discussion, although they acknowledge that “it is still unknown whether small, short-term fluctuations of BP and HR are associated with a higher risk of clinical cardiovascular diseases even if elevated BP and HR can serve as markers for increased risks of cardiovascular diseases”, they go on to make their unfounded statement that prolonged exposure may be harmful to cardiovascular health. And the title and abstract claim the research is about “essential oils” in general rather than Bergamot essential oil specifically.
So, in my opinion, the conclusions are invalid, and the article should not be shared as evidence of effects of essential oils on human health.
Valid or invalid: Essential Oils can help ADHD?
The other shared article titled “Essential Oils Can Help ADHD” posted on the internet by osteopath Dr Joseph Mercola claims that “Research by the late Dr Terry S. Friedmann, a physician who believed in treating the body, mind and spirit as one, showed that vetiver oil was beneficial for children with ADHD.”
On reading the paper by Dr Friedmann (not from a peer-reviewed scientific journal, just from a Meetup website), it turns out that Dr Friedmann’s conclusions about vetiver were based on 4 subjects only, and fails to mention whether the changes in beta-theta wave ratio that he observed were measured while the subjects were being challenged with a task requiring focused attention or not. Dr Friedmann also fails to comment on the fact that the 16 children in the control group (who had no essential oil treatment) also experienced positive changes in their beta-theta wave ratios. It is not valid to make claims of a generalisable therapeutic effect based on results from just 4 subjects.
The other papers Dr Mercola cites as possible evidence for Vetiver being good for ADHD are from an experiment done on sleep-wake hours in rats exposed to vaporised vetiver oil, and one done on alertness of 18 adults without ADHD exposed to vapour from fresh roots of vetiver, not the essential oil!
It would be great if there really was evidence that inhaling essential oils had measurable effects on focus in children with ADHD. However, none of these articles provide sufficient evidence for me. I would not share any of these articles as evidence that essential oils help ADHD.
How to determine quality of a scientific paper
To determine the quality of a scientific paper, two things need to have been done: firstly, the trial needs to have been designed and carried out appropriately; secondly, the report needs to contain sufficient detail for readers to be able to fully understand the trial design, results, discussion and conclusions, including any limitations noted by the authors.
Essential oil users wanting to find out if a scientific paper provides real evidence to support therapeutic claims for an essential oil need to become “quality detectives”. The first question to ask is “Is the full-text available anywhere, rather than just the abstract?” Try Google Scholar or Research Gate, https://www.researchgate.net/ where a lot of researchers publish pre-print versions of their articles.
Once you have the full-text ask these questions:
My dream is to have people using essential oils become scientifically literate enough to critically evaluate scientific papers themselves. Maybe we could start a journal club, where we go through various papers on aromatherapy/ essential oils and critique them as a group?
Please contact me if you’re interested @DrEJoyB or firstname.lastname@example.org