Medical cannabis is a therapeutic agent unlike any other. Formulations are just as varied as the delivery methods by which cannabis medicines can be administered and the many conditions it is proposed to treat. Generally, botanical medicines are infamous in their difficulty to wrangle into the traditional model of standardised conventional medicine and randomised placebo control trials.
While challenges in terms of standardisation of active constituents have largely been overcome in the pursuit of pharmaceutical-grade cannabis formulations, variation and concentration of cannabinoids – each of which has different impacts on disease processes – presents a challenge in terms of discerning the most appropriate dose of patients.
Personalised medicine is an approach that moves away from a one-size-fits-all healthcare model, towards a system that earnestly looks at the individual, their particular needs, genetics, environmental factors and the manifestation of symptoms.
Medical cannabis is the poster child for bringing personalised medicine to the forefront of healthcare. With so many different cannabinoids and the ability to vary their presence in formulations, cannabis medicines are well suited to be personalised to the needs of the patient.
The number one guideline that is widely agreed upon with medical cannabis is “start low, go slow” – in medical jargon, this is called titration. Particularly in relation to THC containing medicines, adverse effects can be experienced if patients are placed on too high a dose, too early in their treatment plan. By and large adverse effects from THC or cannabis as a whole are relatively mild – drowsiness, dry mouth, increased appetite, nausea – it is still important to avoid the occurrence of these through proper titration.
As with all medical treatments, the goal is to achieve the greatest alleviation of symptoms with the least amount of dose – therefore hopefully avoiding any adverse effects whilst addressing the potential for building tolerance to the medication. Once therapeutic benefits are achieved, this is termed optimum dose and is maintained unless symptoms change or the healthcare professional deems the dose should be modified.
Dose optimisation is assessed through preclinical, phase I and II clinical trials and provides physicians with a solid foundation for dosing ranges in a given condition. Yet with a medicine as unique as medical cannabis, nothing can replace real-world experience. Observing individual patients reactions to medical cannabis and applying the tenets of personalised medicines, in conjunction with evidence-based practice is likely to lead to the most success in dosing cannabinoid medicines.
Comparing medical cannabis therapeutic doses
Some of the key factors that play into dosing are the patient’s age, weight and the symptom or condition being addressed. Dosing considerations for children with treatment-resistant epilepsy, for example, are very different from an adult with chemotherapy-related nausea or cachexia.
Let’s compare some broad examples. Animal trials have shown us that lower doses of CBD (2.5-10mg/kg) are often more efficacious than higher ones (20mg/kg) in the treatment of anxiety. Human trials confirm this, in that 300mg-600mg dose of CBD may decrease subjective anxiety and moderate areas of the brain that control fear responses and anxiety.
In terms of treating pain, higher doses of THC are generally correlated with increased pain relief. However some research has shown THC, in smaller quantities, is as effective when combined with CBD. Chronic pain THC doses can range from 10-40mg/day, however, it should be noted that 30mg/day of THC is deemed the limit for most patients before adverse effects are observed – unless titration is carefully managed.
When combined with equivalent quantities of CBD, some research indicates such formulations to be effective for pain with as little as 3-10mg/day THC in a 1:1 ration with CBD. As demonstrated in this example, dosing is dependent on the cannabinoids within the medication.
Due to the synergism of cannabinoids known as the entourage effect, cannabis medicines with a broad spectrum of cannabinoids can exhibit greater effect at lower doses than isolated cannabinoids at higher doses.
Multiple Sclerosis (MS) is another condition where medical cannabis has been reported to provide relief, specifically from symptoms such as spasticity, tremor and pain. Yet when compared to dosing for other conditions, MS patients may require much higher doses of 20-40mg/day of THC.
As you can see, the therapeutic dose varies greatly given the specific symptoms or disease being targeted. It is of utmost importance that dosing is tailored to the individual patient presentation and modified as required in the long term.
By Jessica Kindynis
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