Apomorphine For Parkinson’s Disease: Uses, Dosage, Side Effects
Comprehensive guide to apomorphine use in advanced Parkinson's: administration, benefits, side effects, and patient management strategies.
Apomorphine is a potent dopamine agonist administered subcutaneously to treat motor fluctuations in advanced Parkinson’s disease (PD), providing rapid relief from ‘off’ episodes through intermittent injections or continuous infusion.
About apomorphine
Apomorphine hydrochloride is a highly potent emetic and dopamine agonist derived from morphine but lacking opioid activity. Unlike oral dopamine agonists, it bypasses gastrointestinal absorption issues common in advanced PD, acting directly on dopamine receptors in the brain to alleviate motor symptoms rapidly.
Available as Apo-go (UK pen injector for intermittent use) and Dacepton (infusion solution), it is indicated for patients experiencing unpredictable ‘off’ periods despite optimized oral levodopa therapy. Its rapid onset (typically 5-10 minutes for injections, steady-state via infusion) makes it ideal for sudden akinesia, morning stiffness, or end-of-dose deterioration.
Clinical evidence from multiple studies confirms apomorphine reduces daily ‘off’ time by approximately 50-60%, comparable to levodopa efficacy but with shorter duration, positioning it as an essential adjunct in device-aided therapies.
When is it prescribed?
Apomorphine is prescribed for advanced PD patients with persistent motor fluctuations (‘off’ periods) not controlled by oral/transdermal medications. It targets unpredictable ‘off’ episodes, delayed levodopa onset due to gastric issues, morning akinesia/dystonia, and end-of-dose worsening.
- Intermittent injections: Rescue therapy for sudden ‘off’ states, providing 60% reduction in off-time duration with effects lasting 1-2 hours.
- Continuous subcutaneous infusion (CSAI): For frequent/long ‘off’ periods or peak-dose dyskinesias, reducing off-time by ~60% and dyskinesia scores by ~33% as monotherapy or adjunct.
It is less invasive than deep brain stimulation or levodopa-carbidopa intestinal gel, suitable even when neurosurgery is contraindicated. Early referral to specialist centers improves outcomes.
Apomorphine test dose
A supervised test dose (1-3 mg subcutaneously) confirms tolerability and efficacy before ongoing therapy. Administered in clinic during ‘off’ state, it assesses motor response (UPDRS improvement >20-30%) and side effects like nausea.
Antiemetic pretreatment (e.g., domperidone 20 mg three times daily for 48 hours prior, continued 8 weeks) is mandatory to mitigate nausea/vomiting. Positive test predicts good response; if ineffective, alternatives like levodopa challenge are considered.
How and when to take apomorphine
Intermittent injections (Apo-go pen)
Start with test dose, titrate to effective dose (1-6 mg per injection, max 10 mg/single, 100 mg/day). Inject subcutaneously into abdomen/thigh/upper arm during ‘off’ periods, up to 10-12 times daily. Rotate sites to prevent nodules.
Continuous infusion (Dacepton)
Delivered via mini-pump (e.g., 24-hour capacity) into abdominal wall. Initial dose 1-4 mg/hour daytime, 0.5-2 mg/hour night, titrated over days/weeks to 3-10 mg/hour (mean 4-5 mg/hour). Total daily dose 30-100 mg. Reduce oral PD meds gradually: dopamine agonists first, then MAO-B/COMT inhibitors, finally levodopa.
| Administration Type | Dose Range | Onset/Duration | Max Daily |
|---|---|---|---|
| Intermittent SC injection | 1-6 mg | 5-10 min / 1-2 hrs | 100 mg |
| Continuous SC infusion | 1-10 mg/hr | Steady-state in hours / 24 hrs | 100 mg |
Patients manage pump after training: site changes every 12-24 hours, battery checks. Wake/sleep profiles adjust flow rates.
Cautions and side-effects
Cautions
- Severe cardiovascular disease, respiratory failure, dementia, psychosis.
- Avoid with antipsychotics (risk of blockade).
- Monitor blood pressure, liver/kidney function.
- Not for oral use (emetic).
Side-effects
Common: nausea (48%, mitigated by domperidone), somnolence (25%), injection-site reactions/nodules (28%), hypotension.
- Skin nodules: 2/3 patients; rotate sites, use gel/cream, ultrasound may resolve.
- Haemolytic anaemia: Rare; monitor blood counts.
- Dyskinesias: May increase initially; reduce oral meds.
- Impulse control disorders: Lower risk than oral agonists.
Discontinuation: Easy reversal vs. other device therapies; withdrawal rates similar to oral agonists.
Infusion pump problems
- Battery failure/air in tubing: Backup battery, prime lines.
- Occlusions: Check cannula, change site.
- Site reactions: Sterile technique, hygiene.
- Contact specialist nurse for issues.
Reducing other Parkinson’s medication
Goal: Minimize oral meds to reduce dyskinesias. Sequence: dopamine agonists → MAO-B inhibitors → COMT inhibitors → levodopa (dose then frequency).
In TOLEDO study protocols, this achieved OFF reduction with good tolerability; individualize based on goals.
Further reading and references
Consult Parkinson’s UK, NICE guidelines for PD management.
Frequently Asked Questions (FAQs)
Q: How quickly does apomorphine work?
A: Injections act in 5-10 minutes, lasting 1-2 hours; infusions provide continuous steady-state control.
Q: Is apomorphine suitable for all PD patients?
A: For advanced PD with refractory fluctuations; contraindicated in dementia, severe heart/lung disease.
Q: How do you manage skin nodules from infusion?
A: Rotate sites frequently, use topical treatments; most resolve with care.
Q: Can apomorphine replace levodopa?
A: Adjunct; often reduces levodopa needs by 30-50% but not full replacement.
Q: What if the test dose fails?
A: Consider alternatives like levodopa challenge or other therapies.
References
- Practical use of apomorphine infusion in Parkinson’s disease — Antonini A et al. 2023-10-20. https://pmc.ncbi.nlm.nih.gov/articles/PMC10645621/
- Apomorphine for Parkinson’s Disease: Efficacy and Safety of Current and New Formulations — Garcia Ruiz PJ et al. 2019-10-01. https://pmc.ncbi.nlm.nih.gov/articles/PMC6776563/
- Apomorphine in the Treatment of Parkinson’s Disease — Turkish Journal of Neurology. 2020-01-01. https://www.tjn.org.tr/full-text/128/eng
- Apomorphine (Apokyn) Injection: Uses & Side Effects — Cleveland Clinic. 2024-01-01. https://my.clevelandclinic.org/health/drugs/19850-apomorphine-injection
- Apomorphine | Parkinson’s UK — Parkinson’s UK. 2023-01-01. https://www.parkinsons.org.uk/information/drugs/apomorphine
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