Key Definitions
Introduction
Prior to prescribing medical Cannabis to a patient, certified health care practitioners are urged to consider the following (MacCallum, et al., 2021):
- Precautions and contraindications
- Drug interactions
- Administration route and Cannabis strain safety
- Titration strategy
- Patient monitoring and assessment of symptom control
- Adverse events
- Follow-ups
1. Precautions & Contraindications
Precautions
CBD dominant products and frequent monitoring are advised for patients that have mental health disorders attributed to large THC doses and/or early age Cannabis consumption (MacCallum, et al., 2021).
When a patient has a history of tobacco use, it is strongly advised that oral Cannabis be prescribed over inhaled forms of Cannabis (MacCallum, et al., 2021).
E-Cigarette or Vaping Product Use-Associated Lung Injury (EVALI) has increased in recent years from the use of Cannabis and THC containing vaping products. Research is currently ongoing into which constituents contribute to or cause EVALI and caution is advised that patients only purchase Cannabis and THC containing vaping products from authorised sources (e.g., registered section 21 medical providers) or used vaporisation techniques that utilise dried Cannabis flower (MacCallum, et al., 2021).
THC can lead to neurocognitive and psychomotor impairment, so caution is advised when prescribing THC products to patients that are required to drive or operate heavy machinery (MacCallum, et al., 2021).
Careful consideration is strongly advised when prescribing Cannabis medications to patients under the age of 25 as exposure to large doses of THC and regular use has been linked to risk of persistent cognitive effect, social dysfunction, anxiety, depression and Cannabis used disorder (CUD) (MacCallum, et al., 2021).
When a patient has a history of or suffers from a substance use disorder or CUD, they should be started on treatments involving CBD and their treatments should be closely monitored (MacCallum, et al., 2021).
Contraindications
Cannabis should not be used in patients with unstable cardiovascular disease (CVD) and frequent monitoring is required when prescribing medical Cannabis to patients at risk of CVD and patients with stable CVD (MacCallum & Russo, 2018) (MacCallum, et al., 2021).
Although Cannabis has not been linked to the development of specific respiratory illnesses and lung cancer, inhaled Cannabis is not recommended for patients with respiratory disease (MacCallum & Russo, 2018) (MacCallum, et al., 2021).
Extreme caution is advised in prescribing Cannabis (except CBD dominant preparations) to patients that have a family history or predisposition to bipolar disorder and/or psychosis (MacCallum & Russo, 2018) (MacCallum, et al., 2021).
Cannabis should be avoided by pregnant and breastfeeding individuals (MacCallum & Russo, 2018) (MacCallum, et al., 2021).
2. Drug Interactions
Research to date suggests that Cannabis is safe for use with most available medicines. The following is a non-extensive list of medications that may interact with THC and/or CBD (MacCallum, et al., 2021):
Although the possible drug interactions above exist, studies to date have not demonstrated toxicity or loss of effect of concomitant medications when taking medical Cannabis (MacCallum & Russo, 2018).
If a drug interaction is found, your qualified health care provider must assess if both therapies are required and if the benefits associated with medical Cannabis prescription will outweigh the risk of stopping the other medical prescription (MacCallum, et al., 2021).
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3. Administration Route & Cannabis Strain Safety
Refer to the Preparing & Dosing Medical Cannabis blog post. Before prescribing medical Cannabis note the following (MacCallum, et al., 2021):
- Consider prescribing a CBD dominant medicine before prescribing a THC or THC/CBD medicine.
- Patients with chronic symptoms are recommended to be prescribed oral forms of medical Cannabis.
- Patients that require rapid onset of action are recommended to be prescribed inhaled forms of medical Cannabis.
4. Titration Strategy
Refer to the Preparing & Dosing Medical Cannabis blog post.
5. Patient Monitoring & Assessment of Symptom Control
Monitoring of patients on medical Cannabis treatments is fundamental in ensuring safety of the patient. It is recommended that patients follow-up with their health care providers between 1-6 months of starting their treatment. The frequency of follow-ups should be dictated by the following (MacCallum & Russo, 2018) (MacCallum, et al., 2021):
- Patient’s familiarity with Cannabis
- Patient’s comorbidities
- Patient’s ability to follow a treatment plan
A patient’s treatment plan should include tracking the Cannabis products they are using, routes of administration, doses, adverse events and changes in symptoms (MacCallum, et al., 2021).
To help inform future dosing or direction of treatment, it is recommended that health care professionals assess symptom control through object and validated tools like GAD-7, PHQ-9, BPI etc (MacCallum, et al., 2021).
6. Adverse Events
Although Cannabis has a superior safety profile, when compared with other medications, it does result in some THC-mediated side effects. The following is a list of adverse events (ranked from most to least common) that are associated with medical Cannabis (Amar, 2006) (Hazekamp & Grotenhermen, 2010) (Kowal, et al., 2016) (Legare, et al., 2022) (MacCallum & Russo, 2018):
- Drowsiness /fatigue
- Dizziness
- Dry mouth
- Cough, phlegm, bronchitis (from smoking only)
- Anxiety
- Nausea
- Cognitive effects
- Euphoria
- Blurred vision
- Headache
- Orthostatic hypotension
- Toxic psychosis/paranoia
- Depression
- Ataxia/dyscoordination
- Tachycardia (after titration)
- Cannabis hyperemesis
- Diarrhoea
Using low dose and slow titration techniques (like the ones provided in the Preparing & Dosing Medical Cannabis blog post) and using CBD dominant medications can reduce the effects or mitigate adverse events (MacCallum & Russo, 2018).
7. Follow-ups
It is important for patients to follow-up with their health care providers after titrating their medical Cannabis dose as changes to medications, lifestyle and drug tolerance can impact their treatment. The frequency of future follow-ups should be between 3-6 months (MacCallum, et al., 2021).
Disclaimer
The information presented in this post is intended as an informational guide. The remedies, approaches and techniques described herein are meant to supplement, and not to substitute for, professional medical care or treatment. They should not be used to treat a serious ailment without prior consultation with a qualified health care professional.
References
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