What Is Apomorphine? The Brain-Acting ED Drug, Explained

Almost every ED drug works on blood vessels. Apomorphine works in the brain. Here is what is known about it.

Sildenafil, tadalafil and vardenafil all work the same way: they block an enzyme in the blood vessels of the penis so that sexual stimulation produces a stronger blood-flow response. Apomorphine takes a different route entirely.

What is apomorphine?

Apomorphine is a prescription dopamine agonist, a medicine that acts in place of dopamine, the brain's own signaling chemical.⁴ Its approved U.S. use is as an injection under the skin to treat "off" episodes (times when movement, walking and speech become difficult) in people with Parkinson's disease.⁵⁴ For erectile dysfunction it has been studied as a sublingual tablet, and it is not an FDA-approved ED treatment in the U.S.

How it works

Apomorphine is a dopamine agonist. Dopamine is a signaling chemical involved in arousal, and apomorphine acts on dopamine receptors in the brain, upstream of the blood vessels.¹ That is why it has been studied as a sublingual tablet, dissolved under the tongue so it can be absorbed without passing through the gut.

What the trial found

In a randomized, double-blind crossover trial of 296 men with ED, a 3 mg sublingual dose of apomorphine produced erections firm enough for intercourse more often than placebo. The median time to erection was 18.8 minutes. A 4 mg dose was no more effective than 3 mg but caused more side effects.¹

What is apomorphine used for?

Apomorphine is a dopamine agonist whose use on the U.S. label we checked is treating "off" episodes in advanced Parkinson's disease, as a subcutaneous injection (APOKYN).⁵ For erectile dysfunction it has been studied as a sublingual tablet, and a 2020 review describes sublingual apomorphine as the only licensed oral ED drug not absolutely contraindicated with nitrates,.⁶

Does apomorphine work for ED?

In trials it beat placebo, with modest gains. A 2020 review of nine randomized trials (doses 2 to 6 mg, 4 to 8 weeks) found 6% to 27% more successful intercourse attempts than placebo, with no significant difference in men after radical prostatectomy.⁶

How long does apomorphine last?

No ED trial we reviewed reports how long the effect lasts. The ED trial reported a median time to erection of 18.8 minutes.¹ For context only, the injection label gives a mean terminal elimination half-life of about 40 minutes, but that is for Parkinson's disease dosing and says nothing about how long an erection response lasts.⁵

What dose of apomorphine is used for ED?

The trials used fixed sublingual doses: 3 mg was more effective than placebo and not significantly different from 4 mg, which caused more nausea (14.1% versus 3.3%).¹ The 2020 review pooled doses from 2 to 6 mg and called 2 or 3 mg generally well tolerated.⁶ This is trial information, not a dosing recommendation; a clinician sets any dose.

Is there an apomorphine supplement or pill?

The apomorphine product label we loaded is a prescription injection.⁵ Sublingual tablets in the trials were studied drugs, and where it is used for ED in the U.S. it is in compounded medications, which the FDA does not review for safety or effectiveness.³ None of our sources describes an apomorphine supplement, so be cautious of any product sold as one.

Can apomorphine be taken with other ED medicines?

It acts on a different pathway than sildenafil or tadalafil, which is why combinations exist, but the Viagra and Cialis labels say combining them with other ED treatments has not been studied.⁷⁸ The apomorphine label contraindicates 5-HT3 antagonist anti-nausea drugs such as ondansetron.⁵ Ask a clinician about every medicine you take.

Side effects

Nausea was the most common side effect. In the trial it was reported by 3.3% of men on 3 mg and 14.1% on 4 mg.¹ That dose sensitivity is one reason apomorphine doses are kept low.

What are the effects of apomorphine?

The effects depend on the product. As an injection for Parkinson's disease, apomorphine acts in place of dopamine to control movement, and its most common adverse reactions in a placebo-controlled trial were yawning, drowsiness, dyskinesias (uncontrolled movements), dizziness or low blood pressure on standing, runny nose, nausea or vomiting, hallucination or confusion, and swelling of the extremities.⁵ In that small 4-week trial (20 treated patients, 9 on placebo), yawning was reported by 40% and drowsiness by 35% of treated patients, and none on placebo.⁵

The injection label also warns about sudden sleep onset during daily activities, fainting, hallucinations and psychotic-type reactions, and prolonged painful erection (priapism), reported in 3 of 361 treated men.⁵ MedlinePlus lists nausea, vomiting, yawning, headache and injection site reactions among its common side effects.⁴ These are injection figures in people with Parkinson's disease and do not predict what a low sublingual ED dose would cause. For that dose, the ED trial reported mainly nausea.¹

Its status in the U.S.

Sublingual apomorphine is not sold in the United States as an FDA-approved ED treatment. Where it appears for ED here, it is as part of a compounded medication prepared by a pharmacy for an individual patient, and compounded drugs are not FDA-approved.³

Is apomorphine a controlled drug?

We found no sign that it is. The APOKYN prescribing information we loaded for this page has no controlled-substance schedule and no abuse or dependence section, which is where a scheduled drug's label would normally place them.⁵ It is still a prescription-only medicine, and "controlled" in the narrow legal sense is a question for the Drug Enforcement Administration schedules, which we did not review here.

Apomorphine in combinations

Because it acts on a different pathway, apomorphine is sometimes combined with PDE5 inhibitors. Quattro, from Vea Health, combines it with sildenafil, tadalafil and vardenafil in one sublingual dose.² The individual drugs have their own evidence, but the combination has not been studied as a whole, and the sildenafil label advises that combinations with other ED treatments have not been studied.⁷ A clinician decides whether a combination is appropriate.

Questions readers ask

How does apomorphine work for ED?

It is a dopamine agonist that acts on arousal pathways in the brain, rather than on blood vessels like sildenafil or tadalafil.

What are the side effects of apomorphine?

Nausea was the most common side effect in a clinical trial of sublingual apomorphine, and it was more frequent at the higher dose.

Is apomorphine FDA-approved for ED?

Not in the United States. For ED it is available here only in compounded medications, which are not FDA-approved.

How long does apomorphine take to work for ED?

In a 296-man trial of 3 mg sublingual apomorphine, the median time to erection was 18.8 minutes.

Is there an apomorphine supplement?

The apomorphine label we loaded is a prescription injection, and for ED it is only used in compounded medications. None of our sources describes an apomorphine supplement.

Is apomorphine a controlled substance?

The APOKYN label we loaded lists no controlled-substance schedule or abuse and dependence section. It is a prescription-only medicine; we did not review the DEA schedules themselves.

Further reading

Part of our guide: How ED Medications Work: Timing, Food, Interactions and Combinations

• Sildenafil Headache: How Common Is It?
• Tadalafil With Alcohol: How Much Is Too Much?
• What Is Tadalafil Used For? The Three Approved Uses
• Tadalafil Brand Names: Which Brand Is Used for What