Kynmobi, otherwise known as apomorphine, is a novel dopamine agonist which can be used on an as-needed basis to treat off-episodes in Parkinson’s Disease. Often, patients taking levodopa may experience a wearing-off effect, resulting in return of symptoms. There are many strategies to manage this phenomenon, but this is the first time a dopamine agonist can be used on an as-needed basis. All other dopamine agonists (pramipexole, ropinirole) require regular daily dosing.
This sublingual film is dissolved under the tongue to bypass hepatic metabolism, with a quick onset of 10 to 15 minutes. The starting dose is 10 mg under the tongue, and may be increased at 5 mg increments up to 30 mg. The maximum number of doses is 5 per day, with a maximum total daily dose of 90 mg. Most patients require on average 2 doses per day. Doses must be separated by at least 2 hours.
Patients should drink some water to improve the film’s dissolving action. The film should be placed under the tongue at the back of the mouth. During the dissolving process, the patient should not chew the tablet, swallow the tablet, swallow the saliva or talk.
The most common adverse effect is gastrointestinal upset, which should be pre-treated with domperidone up to 3 days prior to initiation. Also, patients must be monitored in a medical setting during the titration phase due to orthostatic hypotension risk. Other adverse effects related to dopamine agonists include compulsive behaviours, sleep attacks, confusion and somnolence.
Allergic reactions can occur with Kynmobi, which may be related to the active ingredient apomorphine or the preservative sodium metabisulfite. If any case of anaphylaxis (or oral mucosa numbness/pain), a second retrial is not recommended.
As for drug interactions, Kynmobi is contraindicated with 5HT3 antagonists such as ondansetron, granisetron and palonosetron due to severe orthostatic hypotension. Caution should be observed with antihypertensives, alcohol and nitrates as these can also increase the risk. Finally, apomorphine can increase the QT interval, so it should be used with caution with other QT-prolonging drugs.