Dapoxetine Side Effects by Dose: Nausea, Dizziness and the Fainting Risk

Most dapoxetine side effects are the ordinary ones of any SSRI: nausea, dizziness, headache. What makes this drug different is how clearly the rates climb with dose, and one rare effect that deserves proper attention, fainting. The trial data is detailed enough to put real numbers on all of it, which is more useful than the usual unranked list of symptoms.

This guide uses the official Priligy product information and the published analyses of its phase 3 program, covering more than 4,200 men with premature ejaculation, to show how often each effect happens at 30 mg and at 60 mg, what the warning signs of fainting look like, which combinations are dangerous, and when to get help. For dosing rules and timing, see our dapoxetine dosage guide.

The short version

• Nausea is the most common side effect: about 1 in 9 men at 30 mg and about 1 in 5 at 60 mg.
• Dizziness, headache, diarrhoea, insomnia and tiredness all roughly double between 30 mg and 60 mg.
• Fainting with loss of consciousness is rare: 0.06 percent at 30 mg and 0.23 percent at 60 mg in the placebo-controlled trials, against 0.05 percent on placebo.
• Most fainting happened within three hours of the first dose, and it usually came with warning signs.
• Alcohol, dehydration, other serotonin drugs and certain antifungals and antibiotics make things worse.
• Very few men stopped because of side effects: 2.2 percent for nausea and 1.2 percent for dizziness.

How often side effects happen at 30 mg and 60 mg

The Priligy label pools five double-blind, placebo-controlled trials: 1,616 men took 30 mg as needed and 2,608 took 60 mg, either as needed or daily. These are the dose-related effects it reports for as-needed use, with placebo rates for dizziness from a cardiovascular analysis of the same trials (PMID: 21410293).

Side effect	Placebo	30 mg as needed	60 mg as needed
Nausea	Not reported in label	11.0%	22.2%
Dizziness	2.2%	5.8%	10.9%
Headache	Not reported in label	5.6%	8.8%
Diarrhoea	Not reported in label	3.5%	6.9%
Insomnia	Not reported in label	2.1%	3.9%
Fatigue	Not reported in label	2.0%	4.1%
Fainting with loss of consciousness	0.05%	0.06%	0.23%

Looking at any adverse event at all, a pooled analysis summarised by the UK's National Institute for Health and Care Excellence found rates of 35.1 percent on placebo, 47.0 percent on 30 mg and 60.3 percent on 60 mg. About 3 percent of men in each group reported a severe event and 1 percent or fewer a serious one. The placebo figure is a reminder that a third of men report something on a dummy tablet, so the extra burden of the drug is the gap, not the headline number.

Nausea: the one most people notice

Nausea is the effect most closely tied to dose and the most common reason men stop taking dapoxetine. It tends to arrive with the rise in blood levels, one to three hours after the tablet, which is exactly when you planned to have sex. That timing is why it matters more than its medical seriousness suggests.

What helps: taking the tablet with a full glass of water, staying on 30 mg rather than moving up, and not combining it with alcohol. Food barely changes absorption, according to the label, so a light snack is reasonable if it settles your stomach. Nausea often eases after the first few doses as your body gets used to the drug, but if it does not, the 60 mg dose will make it roughly twice as likely.

Dizziness and headache

Dizziness matters more than headache because it is one of the warning signs that can come before fainting. At 60 mg it affects about one man in ten. It is usually brief and linked to standing up, so the simple fixes are to get up slowly and sit or lie down at the first sign. The label also lists postural dizziness, where it only happens on standing, as a separate uncommon effect.

Headache is usually mild. It becomes much more common when dapoxetine is combined with an erection medicine such as sildenafil, because PDE5 inhibitors widen blood vessels and cause headache on their own. A 2025 meta-analysis found headache three times more frequent on the combination than on dapoxetine alone (PMID: 41031773), which we cover in the combination guide.

Fainting: the number that matters

Syncope, meaning a brief loss of consciousness from a sudden drop in blood flow to the brain, is the side effect that shaped how dapoxetine is labeled. The cardiovascular review of the development program counted one case among 1,857 men on placebo, one among 1,616 on 30 mg and six among 2,608 on 60 mg in the phase 3 trials (PMID: 21410293). In healthy volunteer studies, which included more intensive testing, the rate across all doses was 0.64 percent.

Three details make this more manageable than it sounds:

• Most episodes were vasovagal, the same common reflex faint some people have at the sight of a needle. On heart monitors, they showed a slowing or brief pause of the heartbeat rather than a dangerous rhythm.
• Most happened within three hours of dosing and after the first dose.
• Many happened during clinic procedures such as blood draws and standing blood pressure checks, which are known triggers in their own right.

The same review found dapoxetine did not prolong the QT interval on the heart tracing, which is the more worrying rhythm effect some other medicines carry. The risk from a faint is mostly the fall: hitting your head, or losing consciousness while driving.

Warning signs before fainting, and what to do

The label lists the symptoms that often came before fainting in the trials: nausea, dizziness or lightheadedness, palpitations, weakness, confusion and sweating. They typically appeared within three hours of the dose.

If you notice them, the instruction is simple and worth memorising: lie down straight away with your head lower than the rest of your body, or sit down with your head between your knees, and stay there until the feeling passes. Do not try to walk it off. Do not drive or use machinery for the rest of that period. The label also asks prescribers to explain that fainting can occasionally happen without warning, which is why taking the first dose at home is sensible.

Blood pressure on standing

Orthostatic hypotension, a drop in blood pressure when you stand up, was reported in about 1.3 percent of men taking dapoxetine in the phase 3 program (PMID: 21410293). It is why the label asks for blood pressure and pulse to be checked lying and standing before a first prescription, and why anyone with a past orthostatic reaction should avoid the drug.

It also explains the caution with other medicines that lower blood pressure or widen blood vessels. The label names alpha blockers, such as tamsulosin for prostate symptoms, and nitrates. In a formal study, adding dapoxetine to tamsulosin did not worsen standing blood pressure, but the label still advises caution. Nitrates are a firmer line when erection medicines are involved, since those must never be combined with nitrates at all.

Why alcohol makes it worse

In a study the label describes, a dose of alcohol equal to about two drinks did not change dapoxetine blood levels. It did change how people functioned: sleepiness went up, self-rated alertness went down, and attention and processing tests showed an additive impairment. Alcohol also widens blood vessels and dehydrates, both of which make a vasovagal faint more likely.

The label advises avoiding alcohol completely with dapoxetine. In real use, this is the instruction most often broken, because the tablet is taken before sex and sex often follows drinking. If you have been drinking, the lower-risk choice is to skip the dose that night.

Sleep, tiredness and mood

Insomnia affects about 2 to 4 percent of men depending on dose, and fatigue a similar share. The label also lists anxiety, restlessness, abnormal dreams and reduced libido as common, and less often a low or altered mood, confusion or feeling "drunk".

The bigger mood question is who should not take it. The label rules out anyone with a history of mania or severe depression, and advises screening for untreated depression before starting. It says dapoxetine should not replace an antidepressant someone already takes, since the two cannot be combined. In the trials, standard depression and suicidality scales showed no clear signal of treatment-emergent suicidal thinking in adult men, but any new low mood or distressing thoughts are a reason to stop.

Sexual side effects that seem backward

It surprises many men that erectile dysfunction is listed as a common side effect of a drug for premature ejaculation. SSRIs affect sexual function in several ways, and delaying ejaculation can go along with softer erections or reduced desire in some men. The label also lists, less commonly, failure to ejaculate, difficulty reaching orgasm and genital tingling.

If erections weaken on dapoxetine, that is worth separating from pre-existing erectile problems, which are common in men with premature ejaculation. Men who have both conditions often do better treating both, which is the subject of our sildenafil and dapoxetine combination guide.

Eyes: pupil dilation and glaucoma risk

Blurred vision is listed as common. Less often, dapoxetine can widen the pupils and cause eye pain. That matters for one group in particular: people with narrow drainage angles in the eye, who are at risk of acute angle-closure glaucoma, where pupil dilation can trigger a sudden rise in eye pressure. The label advises caution in anyone with raised eye pressure or that risk. Sudden eye pain, redness, halos around lights and blurred vision together are a medical emergency.

Bleeding with painkillers and blood thinners

SSRIs as a class slightly affect platelet function, and the label notes reports of abnormal bleeding. It advises caution when dapoxetine is combined with aspirin, NSAIDs such as ibuprofen or naproxen, antiplatelet drugs and anticoagulants such as warfarin, and in anyone with a bleeding disorder. For occasional on-demand use this is a small risk, but unusual bruising or nosebleeds are worth mentioning to a doctor.

Serotonin syndrome: combinations that are dangerous

Serotonin syndrome is an excess of serotonin activity that causes agitation, fever, muscle twitching or rigidity, sweating and a fast heartbeat, and it can be life threatening. The label forbids combining dapoxetine with, or within 14 days of stopping, any of these:

• MAO inhibitors
• SSRIs, SNRIs and tricyclic antidepressants
• Triptans for migraine
• Tramadol
• Linezolid
• Lithium
• L-tryptophan and St John's wort
• Thioridazine, because of a heart rhythm risk rather than serotonin

It also warns specifically against recreational drugs. Serotonergic drugs such as MDMA, ketamine and LSD may cause serious reactions including arrhythmia, overheating and serotonin syndrome, and sedating drugs such as opioids and benzodiazepines add to drowsiness and dizziness.

Does stopping cause withdrawal?

Daily SSRIs taken for depression can cause discontinuation symptoms when stopped suddenly, including dizziness, irritability and electric-shock sensations. Dapoxetine, used as intended, is taken occasionally, so this is rarely an issue. The label describes a double-blind study that tested it directly: after 62 days of 60 mg, men switched to placebo following daily dosing had slightly more mild insomnia and dizziness than those who had used it as needed. It is another reason not to take it every day.

Daily use raises cardiovascular effects

The cardiovascular review compared as-needed and daily use. Any cardiovascular adverse event occurred in 5.2 percent of men on placebo, 7.7 percent on 30 mg as needed, 16 percent on 60 mg as needed and 24.5 percent on 60 mg daily (PMID: 21410293). Most of that was dizziness, which rose from 2.2 to 14.9 percent across the same groups. The pattern is consistent: more drug, more often, means more side effects, which is why the label restricts dapoxetine to on-demand use.

Higher doses, higher risk

The label notes that fainting and its warning signs appear dose-dependent, with more cases among trial participants given higher than recommended doses. That is directly relevant to the 90 mg single-ingredient tablets and the combination tablets containing 100 mg of dapoxetine sold online. No approved label goes above 60 mg, and there are no efficacy trials above it. Based on the trend from 30 mg to 60 mg, where nausea and dizziness roughly doubled and fainting roughly quadrupled, there is every reason to expect higher doses to carry more side effects, with no evidence of more benefit.

Who is most likely to get side effects

Some men end up with more drug in their blood from the same tablet. According to the label:

• CYP2D6 poor metabolizers, who break the drug down slowly, had about 46 percent higher peak and 90 percent higher total exposure to the active drug fraction at 60 mg.
• Men on moderate CYP3A4 inhibitors, such as erythromycin, clarithromycin, fluconazole, verapamil or diltiazem, should not exceed 30 mg. Potent inhibitors such as ketoconazole, itraconazole and ritonavir, and grapefruit juice in the prior 24 hours, rule dapoxetine out.
• Men with liver impairment: moderate impairment roughly doubled exposure to the active fraction and severe impairment tripled unbound exposure. Both are contraindications.
• Men with severe kidney impairment, where exposure was about twice normal and the drug is not recommended.
• Men 65 and over, in whom safety and efficacy were not established.

When to get urgent help

Seek emergency care for any of these after taking dapoxetine:

• Fainting, especially with an injury or if you do not come round quickly
• Chest pain, a racing or very slow heartbeat, or severe breathlessness
• Agitation, confusion, fever, muscle stiffness or twitching, which can signal serotonin syndrome
• A seizure; the label says the drug should be stopped and avoided in unstable epilepsy
• Sudden eye pain with blurred vision
• Symptoms of mania, such as racing thoughts and reduced need for sleep

Premature ejaculation itself, its causes and its non-drug treatments are covered on our premature ejaculation page.

Medical disclaimer

This article is educational and does not replace advice from a doctor or pharmacist. Dapoxetine is a prescription medicine where it is approved, and it is not approved in the United States. The side effect rates quoted come from clinical trials in selected men without heart disease or mood disorders and may differ in everyday use. Anyone who takes antidepressants, migraine medicines, tramadol, antifungals, certain antibiotics or blood thinners, or has heart, liver, kidney, eye or mood problems, should get medical advice before using it.

References

• Priligy 30 mg and 60 mg film-coated tablets, Summary of Product Characteristics: sections 4.3, 4.4, 4.5, 4.7, 4.8, 4.9 and 5.2 (Menarini; Swedish Medical Products Agency version, revised June 2021).
• Kowey PR, Mudumbi RV, Aquilina JW, DiBattiste PM. Cardiovascular safety profile of dapoxetine during the premarketing evaluation. Drugs R D 2011. PubMed PMID: 21410293.
• National Institute for Health and Care Excellence. Premature ejaculation: dapoxetine. Evidence summary ESNM40, full evidence summary.
• Russo A et al. Efficacy and safety of dapoxetine in treatment of premature ejaculation: an evidence-based review. PubMed PMID: 27456527.
• Efficacy and safety of on-demand dapoxetine in treatment of patients with premature ejaculation: a meta-analysis. PubMed PMID: 31171764.
• Efficacy and safety of on-demand dapoxetine combined with phosphodiesterase-5 inhibitor compared to monotherapy dapoxetine: a systematic review and meta-analysis. PubMed PMID: 41031773.
• McMahon CG. Dapoxetine: a new option in the medical management of premature ejaculation. Ther Adv Urol 2012. PubMed PMID: 23024705.

Related reading on premature ejaculation

For how to start and when to step up, read our dapoxetine dosage guide. For two-in-one tablets, see sildenafil and dapoxetine together and Super Kamagra vs Kamagra. Single-ingredient options such as Duratia 30 and Dapoforce 60 are on our men's health page.