Prescribing

Clinical Use

“Cancer pain” is a correct answer.

“Migraine Headaches” is an incorrect answer.

“Major depressive disorder” is an incorrect answer.

“Central neuropathic pain” is a correct answer.

Two indications where cannabis-based medicines could be prescribed are cancer pain and central neuropathic pain.

Reasoning

Cannabinoids have been used in a number of clinical settings and disease states. Indications include:

• Chronic pain, specifically neuropathic pain
• Chemotherapy-induced nausea and vomiting; and anorexia associated with weight loss in patients with HIV/AIDS
• Spasticity associated with multiple sclerosis
• Seizures associated with refractory epilepsy (Dravet syndrome or Lennox-Gastaut syndrome)

Dose Type

Correct

Inhalation is the correct answer.

Reasoning

The pharmacokinetics of THC and CBD varies as a function of its route of administration. Administration via the pulmonary route can be a convenient, very rapid and efficient method of cannabinoid delivery, allowing self-titration to the desired therapeutic effect.

Incorrect

Inhalation is the correct answer.

Reasoning

The pharmacokinetics of THC and CBD varies as a function of its route of administration. Administration via the pulmonary route can be a convenient, very rapid and efficient method of cannabinoid delivery, allowing self-titration to the desired therapeutic effect.

Titration of Dose

Correct

Start low, go slow and stay low is the correct answer.

Reasoning

A titration period is required to reach a patients’ personalised dose.
The correct dose of any cannabis-based medication is the lowest possible dose that achieves the desired clinical effect with a minimal side effect profile.

Depending upon the indication, it is suggested that during initial titration, doses are evenly spread out over the day and according to individual response and tolerability. Patients may gradually increase the dose until they achieve an optimal daily dosage.

A conservative dosing protocol should be used when managing frail and elderly patients, those with comorbidities, or those taking multiple medicines.
If medicine cessation is required, slow downward dose titration may be applicable.

Incorrect

Start low, go slow and stay low is the correct answer.

Reasoning

A titration period is required to reach a patients’ personalised dose.
The correct dose of any cannabis-based medication is the lowest possible dose that achieves the desired clinical effect with a minimal side effect profile.

Depending upon the indication, it is suggested that during initial titration, doses are evenly spread out over the day and according to individual response and tolerability. Patients may gradually increase the dose until they achieve an optimal daily dosage.

A conservative dosing protocol should be used when managing frail and elderly patients, those with comorbidities, or those taking multiple medicines.
If medicine cessation is required, slow downward dose titration may be applicable.

Contraindications

Correct

Cannabis-based medicines are contraindicated in the context of pregnancy, psychiatric, substance dependence, renal or hepatic disease, cardiovascular disease, and in frail and elderly patients.

Reasoning

There is an incomplete understanding of the safety profile of cannabis-based medicines. Cannabinoids do have a number of important drug interactions which can result in altered pharmacokinetics or pharmacodynamics. With THC containing medicines, extra caution is advised in patients with a history of mental illness, cardiovascular disease, kidney and liver illness, the elderly and frail, and those with dementia. With high dose CBD medicines, caution is advised in patients with kidney and liver illness. Cannabinoids should be avoided in pregnancy and during lactation.
Refer to the Appendix for full tables: Clinical evaluation tools and Medicine Interactions.

Incorrect

Cannabis-based medicines are contraindicated in the context of pregnancy, psychiatric, substance dependence, renal or hepatic disease, cardiovascular disease, and in frail and elderly patients.

Reasoning

There is an incomplete understanding of the safety profile of cannabis-based medicines. Cannabinoids do have a number of important drug interactions which can result in altered pharmacokinetics or pharmacodynamics. With THC containing medicines, extra caution is advised in patients with a history of mental illness, cardiovascular disease, kidney and liver illness, the elderly and frail, and those with dementia. With high dose CBD medicines, caution is advised in patients with kidney and liver illness. Cannabinoids should be avoided in pregnancy and during lactation.
Refer to the Appendix for full tables: Clinical evaluation tools and Medicine Interactions.

Medicine Interactions

Correct

Rifampicin, Dexamethason, Phenytoin, Phenobarbital

Reasoning

Review all medication use beforehand.

A number of commonly prescribed medicines interact with cannabis-based-medicines and can decrease the effect of THC and CBD and vice versa. Many patients will be co-prescribed with a number of other medicines metabolised by the liver’s cytochrome P450 enzymes (CYP450). The potential for drug-drug interactions will increase when taken together with other medicines metabolised by the CYP450 system.

Refer to Appendix: Medicine Interactions for tables listing known and potential interactions.

Incorrect

Rifampicin, Dexamethason, Phenytoin, Phenobarbital

Reasoning

Review all medication use beforehand.

A number of commonly prescribed medicines interact with cannabis-based-medicines and can decrease the effect of THC and CBD and vice versa. Many patients will be co-prescribed with a number of other medicines metabolised by the liver’s cytochrome P450 enzymes (CYP450). The potential for drug-drug interactions will increase when taken together with other medicines metabolised by the CYP450 system.

Refer to Appendix: Medicine Interactions for tables listing known and potential interactions.