Latin name: Valeriana officinalis
Pharmacopoeial name: Valerianae radix
Other names: garden valerian, garden heliotrope, Mexican/pacific/indian valerian
Valerian is a perennial herb dispersed over temperate and sub polar Eurasian zones, naturalised in north-eastern America and now extensively cultivated. Modern day therapeutic indications stem from traditional Greek medicinal uses for insomnia. Dioscorides and Galen referred to the drug as “phu” as an expression of aversion from its offensive odour. In Germany, Valerian is official in the German pharmacopoeia, approved in many commission E monographs and licensed as both a standard medicinal tea infusion and as a standard medicinal, tincture. It is used by itself in fresh pressed juice, drops, tea and tablets, but more often used in many sedative and nerve teas.
The root of valerian is used most commonly for its sedative and hypnotic properties in patients with insomnia, and less commonly as an anxiolytic. Multiple preparations are available, and the herb is commonly combined with other herbal medications.
The chemical composition includes:- sesquiterpenes of the volatile oil (including valeric acid), iridoids (valepotriates), alkaloids, furanofuran lignans, and free amino acids such as gamma-aminobutyric acid (GABA), tyrosine, arginine, and glutamine.
Although the sesquiterpene components of the volatile oil are believed to be responsible for most of valerian’s effects, it is likely that all of the active constituents of valerian act in a synergistic manner to produce a clinical response (1) Research into the physiological activity of individual components has demonstrated direct sedative effects (valepotriates, valeric acid) and interaction with neurotransmitters such as GABA (2,3) Several clinical studies have shown that valerian is effective in the treatment of insomnia, most often by reducing sleep latency.
A double-blind, placebo-controlled trial compared a 400-mg aqueous extract of valerian and a commercial valerian/hops preparation with placebo (4). A total of 128 volunteers completed this subjective study evaluating the effects of single doses of each test compound taken in random order on sleep latency, sleep quality, sleepiness on awakening, night awakenings, and dream recall. Valerian extract demonstrated statistically significant improvement over placebo in sleep latency and sleep quality. There was no difference between valerian extract and placebo in the other two parameters. The commercial valerian/hops preparation resulted in no changes in sleep latency, sleep quality, or night awakenings, and an increase in sleepiness on awakening. Examination of the study subgroups showed that the positive effects of valerian extract on sleep were most significant in older male patients who considered themselves to be poor sleepers, female poor sleepers, younger poor sleepers, smokers, and those who habitually have lengthy sleep latencies. Subjects who rated themselves as habitually good sleepers were largely unaffected by the valerian extract.
In a double-blind study, subjects who described themselves as having lengthy sleep latency wore a wrist activity meter and provided subjective sleep ratings in a study of the effects of valerian (5). Participants received either a 450- or 900-mg dose of an aqueous extract of valerian root or placebo. Single-dose (450 and 900 mg) valerian extract resulted in significant decreases in measured and subjective sleep latency and more stable sleep during the first quarter of the night, with no effect on total sleep time. The 900-mg dose produced increased sleepiness on awakening compared with placebo.
A randomized, placebo-controlled, double- blind, cross-over study involving patients with insomnia confirmed by polysomnography demonstrated no effects on sleep efficiency after a single 600-mg dose of valerian extract, while multiple doses over 14 days resulted in significant improvement in parameters of slow-wave sleep measured by polysomnography. There was a non-significant trend toward reduced subjective sleep latency after the long-term valerian treatment. (6)
Several studies have shown valerian’s efficacy in patients who do not have sleep disturbances. A small study of patients at home and eight patients at a sleep laboratory who received two different dosages (450 and 900mg) of an aqueous extract of valerian root demonstrated that both groups experienced a greater than 50 percent improvement in sleep latency and wake time after sleep onset. (7)
A recent systematic review of randomized trials of the effect of valerian on patients with insomnia found nine randomized, double-blind, placebo-controlled trials that met the inclusion criteria (8). Two studies showed improvement in sleep-related parameters in patients with insomnia who received repeated administration over two to four weeks (9,10). Another study demonstrated effects after days 1 and 8 in slow-wave sleep, but no effect on subjective measures of sleep (11). Results were contradictory in six acute-dose studies (4,,5,7,12,13). The authors pointed out the wide variety of methodologies used in the studies, and the lack of attention to factors such as randomization, blinding, compliance, withdrawal, confounding variables, diagnostic criteria, and statistical analysis.
A recent multicentre compared a 600-mg dose of valerian extract with 10 mg of oxazepam over a six-week period in 202 patients who were diagnosed with non-organic insomnia (14). The two agents were equally effective in increasing sleep quality as measured by the Sleep Questionnaire B (SF-B), and these results were confirmed by subscales of the SF-B, the Clinical Global Impression Scale, and the Global Assessment of Efficacy.
Valerian has also been used as an anxiolytic, frequently in combination with other herbal preparations such as passion flower and St.John’s wort. One randomized, double-blind, placebo-controlled trial compared valerian (100 mg) with propranolol (20 mg),a valerian- propranolol combination, and placebo in an experimental stress situation in 48 healthy subjects (15). Unlike propranolol, valerian had no effect on physiologic arousal but significantly decreased subjective feelings of somatic arousal.
In a recent preliminary, randomized, double- blind, placebo-controlled trial, patients with a diagnosis of generalised anxiety disorder were treated with placebo, diazepam in a dosage of 2.5 mg three times daily, or valerian extract in a dosage of50 mg three times daily for four weeks (16). Dosage was regulated at one week if an interviewing psychiatrist deemed an increase or decrease necessary. The authors found a significant reduction in the psychic factor of the Hamilton Anxiety Scale (HAM- A) with diazepam and valerian.
Another randomised controlled trial compared 120 mg of kava,600 mg of valerian, and placebo taken daily for seven days in relieving physiologic measures of stress induced under laboratory conditions in healthy volunteers (17). Valerian and kava, but not placebo, significantly decreased systolic blood pressure responsivity, heart rate reaction, and self-reported stress.
According to Commission E monographs, there are no contraindications to valerian (18). Reported adverse effects of valerian are rare. No evidence of potentiation of valerian effects by concomitant ingestion of alcohol has been found in animal and human studies, but the combination should still be avoided. Valerian may potentiate the sedative effects of barbiturates, anaesthetics, and other central nervous system depressants (1,19) Perhaps because of the poorly defined effects of valerian on GABA neurotransmission, valerian appears to attenuate benzodiazepine withdrawal symptoms in animals and humans (20,21)
Keywords: insomnia; anxiety
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