October 2020 listing wrap-up

Apomorphine solution for injection is now listed on the PBS General Schedule (Section 85) as maintenance therapy for the treatment of Parkinson disease, as Authority Required (Streamlined).²

The three new items are:^1,2

• 12142C apomorphine hydrochloride hemihydrate 100 mg/20 mL injection, 5 x 20 mL vials (Apomine Solution for Infusion)
• 12133N apomorphine hydrochloride hemihydrate 30 mg/3 mL injection, 5 x 3 mL cartridges (Apomine Intermittent)*

• 12137T apomorphine hydrochloride hemihydrate 30 mg/3 mL injection, 5 x 3 mL pen devices (Movapo Pen)*

*Note that PBS items apomorphine injection 30 mg/3 mL pen devices and apomorphine injection 30 mg/3 mL cartridges are equivalent for the purposes of substitution by pharmacists at the point of dispensing.²

Existing listings for apomorphine solution prescribed for the treatment of Parkinson disease under the Highly Specialised Drugs Program (Private and Public Hospital) have also been altered to include the addition of new clinical criteria.^1,2

What is it?

Apomorphine is a direct acting dopamine receptor agonist.^3,4

In the treatment of Parkinson disease, apomorphine is believed to directly stimulate postsynaptic D₂ receptors. Stimulation of presynaptic D₂ dopamine receptors and antagonism of alpha₂ adrenergic receptors may also be important.^3,4

Apomorphine reduces tremor, rigidity and bradykinesia in patients receiving levodopa – the precursor to dopamine and first line treatment for Parkinson disease.^3,4,5

Apomorphine is rapidly and completely absorbed from subcutaneous tissues. This and its rapid clearance contribute to rapid onset and brief duration of action.^3,4

Who is it for?

Apomorphine is indicated to reduce the number and severity of ‘off’ phases for patients with Parkinson disease who are severely disabled by fluctuations in motor performance.^3,4

PBS clinical criteria for apomorphine require that patients have:²

• experienced severely disabling motor fluctuations which have not responded to therapy
• commenced treatment in a specialist unit in a hospital setting.

What does the product information say?

Apomorphine is generally only considered suitable for patients with Parkinson disease who are capable of recognising and anticipating ‘off’ phases in motor performance.^3,4

Long term specialist supervision of patients taking apomorphine is advised.

Conventional therapy should be continued during ‘on’ phases.^3,4

For more information see the product information for the relevant apomorphine formulation being considered.

Safety issues

Overall, the incidence of adverse events seems to be generally higher in patients receiving continuous subcutaneous apomorphine infusion than in those treated with intermittent injections.^6,7

Apomorphine is highly emetogenic and patients should be established on domperidone for at least 48 – 72 hours prior to initiation of therapy to reduce nausea and vomiting.^3,4,8

Common adverse effects with apomorphine include:^3,4

• nausea and vomiting (see above)
• transient sedation
• somnolence
• neuropsychiatric disturbances.

Neuropsychiatric disturbances

Hallucinations and confusion may occur with apomorphine.^3,4,8

Patients with symptoms and/or a history of serious psychiatric disorders are at increased risk of psychiatric adverse effects such as impulse control disorders from dopamine agonists including apomorphine.^3,4,8

Impulse control disorders associated with dopamine agonists including apomorphine can include problem gambling, hypersexuality, compulsive spending or buying, and binge eating.^3,4,8

Patients who develop impulse control disorders are at increased risk of dopamine agonist withdrawal syndrome with severe symptoms that may include agitation, anxiety, panic attacks, depression and drug craving.⁸

Frequency and severity of adverse effects should be monitored carefully at regular intervals with dose adjustments or discontinuation as needed.^3,4

See the product information for important steps to follow when starting treatment with apomorphine.

See the PBS Summary of Changes for a complete list of all additions, deletions and alterations.