This post was written by Natasha Clarke, an MSc student at the University of Liverpool.
Many current drinkers report drinking to
excess, therefore it is important to identify treatments which can reduce these
drinking levels, even if the reductions are modest. Medicines derived from
natural products that have few side effects and low toxicity are desirable. Kudzu extract, a Chinese herbal medicine, has long been used
to treat alcoholism and reduce hangover symptoms in Asian cultures. A previous
study reported that treatment with kudzu extract led to significant reductions
in alcohol consumption in heavy drinkers over the course of a week (Lukas et al, 2005).
This randomised, double-blind, placebo
controlled study was designed to see if treatment with kudzu extract (NPI-031)
over a longer period of 4 weeks would reduce alcohol consumption. It was
conducted in Boston and published in Psychopharmacology. Authors found a modest reduction in alcohol
consumption, and the kudzu extract was well-tolerated
with minimal side effects.
Methods
The study recruited 21 male heavy drinkers aged
21-33 years, of whom 17 completed the study. Only males could take part because
kudzu extract may interfere with oestrogen activity.
The study had a 2-week baseline period, 4 weeks
of medication (or placebo) and a 2-week follow up. Participants were assigned
to receive either kudzu extract or a placebo, and they attended the laboratory
twice per week for the first 6 weeks and once per week in the follow-up
fortnight. Alcohol and other drug use were monitored
with self-report measures which were validated with breath, urine and blood
samples. Safety of the kudzu
extract was monitored by assessments of vital signs, daily reports, weekly
assessments of adverse events, blood sample testing and an ECG at the end of
the study.
Results
•
During the
4 weeks when participants received medication (or placebo), participants who
received kudzu extract reported significant reductions in drinking compared to
baseline. Participants in the placebo group also reported reductions in
drinking compared to baseline, although these reductions were not statistically
significant. However, differences between the kudzu extract and placebo groups
were only statistically significant during the third week of receiving
medication. Overall, the interaction between medication group and study week
was statistically significant (p=0.034, ηPartiall²= 0.146), which reflects
the reduction in drinking compared to baseline in the kudzu extract group
only. However, it seems that the
study was underpowered to detect differences between kudzu extract and placebo.
•
There were also differences
between the kudzu-treated and placebo groups in terms of the number of days per
week that they drank heavily, as revealed by main effects of time (p<0.005, ηPartiall²= 0.197) and drug (p=0.008, ηPartiall²= 0.386). Relative to baseline, the
kudzu group showed a reduction in heavy drinking days on the first, third and
fourth treatment weeks (but not the second week). Differences between kudzu and
placebo were only statistically significant on week 4, which again seems down
to low statistical power.
•
Importantly, these reductions
in drinking in the kudzu extract group (compared to baseline) were maintained
during the two-week follow-up period, after they had stopped taking the medication.
•
The
medication also influenced the number of days that participants remained
abstinent from alcohol during the treatment phase. Nine out of 10 participants
in the kudzu extract group achieved three or more consecutive days of
abstinence, compared to only three out of seven participants in the placebo
group. This difference was statistically significant, although we have to again
note the small sample size and the fact that 3 of 10 participants originally
assigned to the placebo group did not complete the study, as opposed to only
one of the 11 participants assigned to the kudzu group.
•
There were
no indications that kudzu extract altered desire for alcohol.
•
Medication
adherence was excellent.
•
There were
no adverse events and changes in vital signs, blood chemistry and renal or
liver function.
Conclusions
The researchers stressed that their most
important finding was that 4 weeks treatment with the kudzu extract led to a
reduction in self-reported alcohol consumption in heavy drinkers who were not
seeking treatment. It also increased the number of consecutive days that
participants did not drink alcohol.
Overall, it seems that kudzu extract could be a
useful add-on to other treatments for problem drinking. However, the sample
size in this study was very small and differences between kudzu extract and
placebo were not consistent across time, so a much larger randomised controlled
trial (RCT) is needed.
This study suggests that kudzu extract can
result in a desirable reduction in drinking (compared to baseline), with no
adverse side effects, and it may be beneficial when combined with a
comprehensive treatment program. However, this study only tested this effect in
Males, and for safety reasons they could not test the drug in Females. Which is
a shame!
Link to paper
Lukas SE, Pentair D, Su Z, Geaghan T, Maywalkt
M, Tracy M, Rodolico J, Palmer C, Ma Z, Lee DY-W. A standardized kudzu extract (NPI-031) reduces alcohol
consumption in nontreatment-seeking male heavy drinkers. Psychopharmacology 2013, 226: 65-73.
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