To enable an approval for access to medicinal cannabis, a clinical justification for the use of medicinal cannabis for the patient’s specific medical condition must be documented. The clinical justification should include:
- A summary of the patient’s unmet medical need(s).
- The clinical justification sources indicating the potential benefit of a medicinal cannabis therapy for the patient.
- A proposed therapeutic treatment plan outlining the terms of the therapy period, including dosing strategy and monitoring and evaluation arrangements.
Selecting a suitable formula
Once you have determined there is a clinical justification for the use of medicinal cannabis, a suitable formula may be selected. Review the available information regarding medicinal cannabis formulations, routes of administration, and dose as they pertain to the patient’s unmet medical need(s).
If you require further assistance identifying a suitable formula for your patient, please contact us and a member of our medical services team will get in touch.
There is no scientifically defined dose of medicinal cannabis for any specific medical condition. The dosage and timing of dosing will vary highly across patients and should be targeted to maximise the therapeutic benefits and minimise unwanted adverse effects.
Consistent with TGA recommendations and international guidelines, the general approach to dosing should be to “start low, go slow”. Patients should be advised that a titration period of several weeks may be required to determine the optimal dose. Although most patients will find their ideal dose in the first few days, individual circumstances may vary, and it may take longer for others to identify the optimal dose.
Initial Treatment Plan
The TGA suggests that an initial treatment plan indicate that the medicinal cannabis product be used for a one-month trial to determine the effectiveness of the medication for the patient’s condition/symptoms. The initial treatment plan should clearly indicate the treatment goals for medicinal cannabis use as well as the starting and stopping guidelines. It is recommended that these be clearly documented and discussed with the patient, related to the symptoms for which the patient is prescribed the medicinal cannabis product and, if possible, should be measurable. Examples include weight gain in patients with cachexia, cessation or minimisation of nausea and vomiting, and improved function and quality of life in patients with chronic non-cancer pain.
The initial treatment plan should also indicate:
- The monitoring arrangements – including communication with the patient weekly, fortnightly, or monthly to establish perceptions of efficacy in symptom management, or perform any blood tests, specialist reviews, or other investigations (as needed) for the particular medical condition and/or symptoms being treated.
- An exit strategy for situations where the medicinal cannabis product is not helping to manage the symptoms, the goals of treatment are not reached, or the patient is dissatisfied.
- That informed consent has been obtained and the patient provided with information about the medicinal cannabis product, possible side effects and treatment goals, and that treatment will be discontinued if benefit has not been demonstrated.
In addition to the above if the product is being prescribed by a general practitioner for a pre-existing condition for which the patient is already consulting a specialist, support for the use of the medicinal cannabis formula should be sought from the consulting specialist and their acknowledgement should be documented.
Medicinal cannabis is contraindicated in patients:
- Who are allergic or have a hypersensitivity to cannabinoids
- Who have a personal or family history of serious psychiatric disorders (particularly schizophrenia)
- Who have unstable cardiovascular disease
- Who are pregnant, planning on becoming pregnant or are breastfeeding
Medicinal cannabis, like any medicine, may have side effects for some individuals. In the case of medicinal cannabis, most of the commonly reported side effects are minor and temporary. The most commonly reported side effect when taking medicinal cannabis products is mild or moderate dizziness and disorientation. For most people, this is most frequent in the first few weeks of treatment. Since CBD is minimally psychoactive, individuals taking CBD only medicinal cannabis products are likely to experience fewer side effects than those taking formulas that contain THC.
Patients should be informed that they must not drive or operate machinery while taking medicinal cannabis products which contain THC. Measurable concentrations of THC can be detected in saliva for many hours after administration and in urine or blood for several days or week after use.
Safety and Toxicity
Medicinal cannabis products are generally regarded as having low acute toxicity. However, concurrent use of other drugs may mask the effects of cannabis and severe toxicity including adverse cardiovascular effects and death may be under-recognised.
In mammals, the median lethal dose of THC has been estimated to be >800mg/kg. CBD appears to be of very low toxicity. Doses of 1000mg/kg CBD appear to have been tolerated safely in humans.