Thursday, 17 January 2019

Prove its efficacy and safety first – Letters – The Star Online

THE Star Online last week reported the Deputy Health Minister of Malaysia’s response to Thailand approving marijuana for medical use and research (tinyurl.com/star-cannabis). Marijuana is also known as cannabis, or ganja in Malay.

Accor­ding to Deputy Minister Dr Lee Boon Chye, pharmaceutical firms wishing to register the drug for such use must provide the required standard information on its quality, efficacy and safety.

Under Malaysian law, cannabis is defined as “any part of any plant of the genus Cannabis from which there is found to be present resin irrespective of its quantity, and by whatever name the plant may be designated”. In addition, “cannabis resin” means “the separated resin, whether crude or purified, obtained from any plant of the genus Cannabis”. The resin is sometimes referred to as hash or hashish, and contains a higher concentration of the active ingredients.

The Poisons Act 1952 lists cannabis in the narcotic substances category. Cannabis, its resin, extracts and tinctures are classified as doctor’s prescription-only preparations.

The law also states that cannabis and its related derivatives when contained in corn paint – used to remove thick, hardened patches of skin on the foot or hand – may be obtained from a doctor or pharmacist. Cannabis was the chemical of choice in corn paint because of its antibacterial property in combating the many microbes that caused skin diseases. It was also used in paints and liniments because of the natural green, psychologically-soothing colour it imparts to these products.

This means that the use of cannabis in medical practice is not new. However, the medical cannabis-containing products have mostly, if not totally, disappeared due to issues of safety and costs. In Malaysia, control of cannabis and its related products in terms of possession, cultivation, import-export, manufacture, sale and distribution comes under the Dangerous Drugs Act 1952 and its regulations.

However, there are currently no cannabis-containing products registered with the drug control authority in Malaysia.

Cannabis is now known to consist of at least 421 compounds, two of which are well-known and most-studied. The first is tetrahydrocannabinol or THC. This is the ingredient that produces hallucinations – that is, the bad effect. Users are said to become “stoned”, meaning having an impaired perception of time and surroundings, failure to engage in coherent communication, and experiencing diminished cognitive ability.

The second important chemical is cannabidiol (CBD). This is the “good” side of cannabis, having effects opposite to THC, and it is non-psychoactive. CBD may have benefits in reducing pain, especially post-injury or post-surgery. Hence, the current practice of using highly addictive opioids as painkillers may be reduced. CBD also seems to enhance cognitive performance, apart from improving the immune function in certain diseases, and reducing inflammation in some types of disorders.

Hence, for cannabis preparations to be useful for medical purposes, the balance of the two chemicals must favour CBD. Typically for medical cannabis, the ratio of CBD to THC should be one to one or two-to-one. When there is too much THC in the preparation, it is classified as recreational cannabis.

Due to its intoxicating properties, not to mention how it makes the heart beat faster, cannabis has long been considered an undesirable drug, and hence outlawed all over the world. However, in recent years, there have been moves by some countries to legalise using cannabis for medical purposes.

The problem is, despite hundreds of clinical trials and case reports regarding cannabis-based products the world over, only a handful have been marketed. These products are claimed to be effective for alleviating pain in the mouth, countering muscle weakness, improving appetite, inhibiting vomiting and preventing certain types of epileptic attacks.

Interests in retro chemicals, like those derived from cannabis, as potential medicines is not exactly a contemporary phenomenon. Due to high costs, scarce discovery of new chemicals, and lengthy laboratory-to-market processes, pharmaceutical companies are revisiting known compounds to search for potential medicines.

In pharmacy, the terms drug repurposing, drug repositioning and drug rescue are used to describe strategies of using old, failed, out-of-favour or existing drugs for new and alternative treatments. The products of such strategies account for more than 30% of recent US Food and Drug Administration-approved drugs and vaccines, generating about US$500bil (RM2 trillion) for the pharmaceutical industry.

Drug repurposing with the aim of “sanitising” currently illegal drugs for use in medical practice is not limited to cannabis. Morphine, for instance, has been a mainstay as a powerful analgesic in alleviating extreme pain in cancer and major trauma. Lately, the recreational drug popularly known as MDMA or ecstasy is reported to be able to change behaviour in interpersonal interactions. An American Journal Of Neuroscience article suggests that MDMA may help people regain trust after being betrayed, hence it is being tested as a supplemental treatment for post-traumatic stress disorder.

Thus Dr Lee’s contention that evidence must be provided of the quality, efficacy and safety of cannabis – or any other drug – to be registered for medical use complies with the requirements of drug-related laws in the country.

ABU BAKAR ABDUL MAJEED

Brain Research Laboratory, Faculty of Pharmacy

Universiti Teknologi Mara

Source: https://www.thestar.com.my/opinion/letters/2019/01/02/prove-its-efficacy-and-safety-first/

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