Kratom (Mitrogyna Speciosa) is a tree indigenous to South East Asia, with leaves containing the psychoactive alkaloids mitragynine and 7-Hydroxymitrogynine. It has a long tradition of use by farmers and other manual workers in its native region, who claim it increases productivity. In recent years, the leaves of this plant (usually prepared as a tea) have been gaining popularity internationally, especially in the US. Whilst not under international control (as is often the case with ethnobotanical psychoactives) its legality varies between regions and countries. Little is known about extent of use in Europe, particularly in countries where it is illegal such as the UK, having been controlled under the Psychoactive Substances Act since 2016.

There several types of Kratom, characterised by different colour ‘veins’ in the leaves and sometimes different growing regions, which are said to have impact the plant’s primary indications. Differences in preference for particular types of kratom are not yet well understood. Laboratory analysis has so far detected no significant difference in the major alkaloids in the resulting plant matter, and the plants which produce the different colour veins are not separate ‘strains’ of kratom in the true botanical sense. It is possible that asides from these two well-known alkaloids, there are other compounds within the plant which also produce an effect, either alone or in combination, which may account for these subjective differences.

Kratom is consumed orally. It is usually sold as a dried greenish powder, which can be swallowed neat, chewed, or prepared as a tea or cold beverage. Less frequently, it is sold in capsule or concentrated extract form.

Kratom contains over 40 different alkaloids, plus a number of other compounds. The two which attract the most attention are mitragynine and 7-hydroxymitragynine; alkaloids which act as partial agonists on the opioid receptors, meaning they produce somewhat similar, but milder, effects to opioid-based medications. This is partly due to the low concentrations of psychoactive compounds within the plant matter (usually 1 – 1.5%) meaning relatively large amounts of kratom needs to be consumed before a noticeable psychoactive effect occurs. Bodily effects maybe noticeable at slightly lower doses; some users report the principle (or only) effect as being an absence of fatigue or pain. Interestingly, mitragynine also has a broad affinity with many other receptors in the body, potentially explaining its complex effect on energy and mood.

There is evidence that in smaller quantities, kratom can produce a mild stimulatory effect, hence its traditional use as a aid with hard, physical labour. These stimulatory effects are not generally considered intense enough to attract the interest of those who use ‘party’ or ‘club’ drugs such as amphetamines. In larger doses, it may have an analgesic quality, and also possess sedating and muscle-relaxing effects.

Kratom is not widely used for recreational purposes – it is more commonly used for self-medication. Emerging data suggests that outside of its traditional context, kratom is more frequently used in an attempt to address chronic pain, sleeplessness, and/or to support opioid addiction withdrawal and recovery. More research is needed to scientifically assess its potential therapeutic applications, but the anecdotal evidence for these effects is strong.

Kratom is less likely to cause harm to health than many other illicit drugs and prescription medications, particularly those from the opioid family, of which it mimics some effects.

None the less, there some side-effects of kratom. Similar to opioids, it can produce agitation, tachycardia, constipation, vomiting and nausea. It does not, however, appear produce the respiratory depression which is characteristic of opioid overdoses. There have been a small number (this varies according to the source consulted) of fatalities internationally where kratom was implicated. This was usually because kratom was detected on post-mortem toxicology. However, in almost all cases, a number of different drugs were detected, which may contributed to, or been responsible for, the death. According to the US Center for Disease Control (CDC)  ‘Postmortem toxicology testing detected multiple substances for almost all decedents…Fentanyl and fentanyl analogs were the most frequently identified co-occurring substances.’ It also needs to be considered that as the vast majority of regular kratom users report experiencing chronic pain, or are in recovery from addiction to another substance, they are already at increased risk of death in any given year. Interestingly, no deaths attributed to kratom have been reported in Asia.

People who have impaired liver function, or who are taking prescription medications which may be changed by the liver, may be more at risk of harm, as kratom is believed to temporarily slow down functioning of this organ.

Taking more than one psychoactive drug at a time is always riskier than taking a single substance. Consuming Kratom alongside other opioids (whether illicit drugs or prescribed medications) may be very dangerous, as this likely to potentiate the effects, and the risks of each substance increase. Using alcohol will also raise the likelihood of experiencing negative effects. Little is known about this combination, but in general, central nervous system depressants such as alcohol pose even more risk when combined with either stimulants or sedatives.

There is some evidence that kratom may cause dependence, if taken in sufficient quantities for an extended period of time. Some people report difficulty in stopping or reducing daily use. Withdrawal symptoms are likely to be much milder than those associated with opioids, bearing in mind one of the most common uses of Kratom is to lessen the effects of opioid withdrawal in those with existing issues with addiction. As previously mentioned, the most common mode of use is oral ingestion, which does not lend itself as easily as to addiction, as the onset of effect is longer and milder due to the metabolisation process which accompanies this.

Kratom is a comparatively low-risk substance when taken in small doses. Those who have decided to use kratom are advised to begin with small amounts, as individual tolerance levels will vary. Taking too much kratom can be unpleasant; nausea vomiting and dizziness are common side effects in such instances. Concentrated preparations, such as liquids, are best avoided – accurate dosing is difficult as the strength is often unknown There may be other ingredients present which pose risks of their own – as with any drug purchased in a non-regulated market, there is always the possibility of adulteration. As noted above, kratom can produce mild withdrawal symptoms after regular use, so caution is advised with regards to frequency of consumption.

The US Food and Drug Administration declared kratom to contain ‘opioid agonists’ in 2018, and The CDC states that Kratom is not an opioid. Nonetheless, its action on the Mu-opioid receptors means kratom is sometimes erroneously ‘lumped together’ with opioids such as morphine and heroin. It does not display the same properties, and does not pose the same level of risk of abuse, or in terms of respiratory depression (Opioids such as heroin, suboxone etc can slow breathing down to such an extent that it can cause death – a 2019 review concluded this was not the case with kratom).

In 2016, the Drug Enforcement Administration expressed intent to place both mitragynine and 7-hydroxymitragynine into schedule 1, which would have made possession or sale of kratom illegal across the US. Protesters organised a march and a petition, which garnered over 120,000 signatures to oppose the ban. Of the 23,116 comments which were submitted during the public consultation, 99.1% supported kratom, and included positive accounts from a large number of law enforcement officials, heath care professionals and scientists, who overwhelmingly stressed its potential role in addressing the opioid epidemic currently facing the US.

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