You’ve taken your first tablet, or you’re thinking about starting one, and now you want the honest answer. What side effects can tadalafil 5mg cause, and should you worry?
The short answer is this. Most tadalafil 5mg side effects are mild and short-lived, and the most common ones are headache, indigestion, back pain, muscle aches, flushing, and a blocked nose. Rare but serious problems can happen, so it helps to know what’s normal, what isn’t, and when to seek urgent help.
This guide explains the side effects in plain English, why they happen, what you can do about them, and when to speak to a pharmacist, prescriber, 111, or A&E.
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Five key takeaways
- Headache is the most commonly reported issue with tadalafil 5mg in a daily-use study.
- Most common side effects are linked to blood vessel and muscle relaxation, which is how the medicine works.
- Many mild effects settle on their own, especially as your body gets used to the medicine.
- Urgent help matters for red-flag symptoms, especially chest pain, sudden vision or hearing loss, or an erection lasting over 2 hours according to NHS urgent advice.
- Drug interactions matter, especially with nitrates and some blood pressure medicines.
What tadalafil 5mg side effects are most common
If you search online, you’ll often find long scary lists. In real life, individuals typically want to know the handful of side effects they’re most likely to notice.
For tadalafil 5mg daily, the commonest side effects are usually:
- Headache
- Indigestion
- Back pain
- Muscle aches
- Facial flushing
- Nasal congestion or a stuffy nose
In one clinical study of 80 men taking daily 5mg tadalafil, headache affected 13 out of 80 patients (16.25%), lower back pain 11 out of 80 (13.75%), dyspepsia or indigestion 8 out of 80 (10%), gastro-oesophageal reflux 4 out of 80 (5%), and myalgia or muscle pain 3 out of 80 (3.75%). The side effects were described as mild and tolerable, and there were no discontinuations [1].
The NHS also says common tadalafil side effects include headache, indigestion, back pain, muscle aches, flushing, and nasal congestion, and classifies common side effects as affecting more than 1 in 100 people [2].
| Side effect | What it may feel like | What usually helps |
| Headache | Tight, pressure-like ache, often mild to moderate | Fluids, rest, simple pain relief if suitable for you |
| Indigestion | Burning, bloating, reflux, uncomfortable upper tummy | Smaller meals, avoiding heavy food, antacids if suitable |
| Back pain | Aching lower back, often later in the day or next day | Gentle movement, warmth, simple pain relief if suitable |
| Muscle aches | General ache in thighs, back, or other muscles | Rest, fluids, light stretching |
| Flushing | Warm, red face or neck | Usually settles on its own |
| Blocked nose | Stuffy feeling, especially after dosing | Often brief and mild |
Practical rule: Mild side effects are common. Severe, sudden, or unusual symptoms are not.
Featured snippet answer
What are the most common tadalafil 5mg side effects?
The most common tadalafil 5mg side effects are headache, indigestion, back pain, muscle aches, flushing, and nasal congestion.
Why tadalafil causes side effects in the first place
This is the part many people never get told. The side effects often make more sense once you know why the medicine works.
Tadalafil is a PDE5 inhibitor. In simple terms, it helps your body keep more of a chemical signal called cGMP. That signal relaxes smooth muscle and widens blood vessels [3]. That’s helpful for erections and some urinary symptoms, but it can also affect other parts of the body.
Blood vessels relaxing
When blood vessels widen, you may notice:
- Headache
- Flushing
- A light dizzy feeling in some people
That headache doesn’t mean the medicine is “wrong” for you. Often, it means your blood vessels have responded to the drug’s effect.
Smooth muscle relaxing
Tadalafil can also relax smooth muscle in places other than the penis. That can lead to:
- Indigestion
- Reflux
- A bloated or unsettled stomach feeling
The reason is simple. If the valve between the stomach and food pipe relaxes a bit, acid can move upwards more easily.
Muscle and back aches
Back pain and muscle aches confuse people because they don’t sound like an erection medicine side effect. But these symptoms are recognised in NHS and MHRA-approved information [2], [3].
The MHRA-approved patient leaflet notes that back pain and myalgia can peak around 12 to 24 hours after a dose, which explains why some people feel fine at first and then notice aches later that day or the next morning.
For a more detailed analysis to explain why tadalafil can cause back aches, read Comprehensive literature review: Side effects of Tadalafil and PDE5 inhibitor selectivity
Tadalafil’s benefits and its side effects come from the same core action. It relaxes blood vessels and smooth muscle. That’s useful, but it can create temporary knock-on effects elsewhere.
Featured snippet answer
Why does tadalafil 5mg cause headache and indigestion?
Tadalafil can widen blood vessels and relax smooth muscle. That can trigger headache, flushing, indigestion, and reflux.
How long do side effects usually last
People often experience anxiety. A mild headache or backache can feel more alarming when you don’t know whether it should pass in an hour or linger all week.
Tadalafil has a long half-life of about 17.5 hours, which means it stays in the body longer than some other erection medicines [3]. Because of that, side effects can sometimes appear later and may not vanish straight away. However, research suggests that the daily use of tadalafil 5mg can help the body become used to these side effects, which then diminish with prolonged use [3].
What does that mean day to day
You might notice:
- Headache or flushing fairly soon after a dose
- Back pain or muscle aches later, often within the next 12 to 24 hours
- Mild symptoms fading on their own
In the daily tadalafil 5mg study, the reported side effects were generally mild, tolerable, and largely resolved spontaneously, with no one stopping treatment because of them [1].
That doesn’t mean you should ignore symptoms that persist or feel severe. It means a mild side effect on its own is often expected, especially early on.
Real-life example 1
A busy parent takes tadalafil 5mg in the evening after the kids are in bed. He wakes with a dull headache and a warm face. He drinks water, eats breakfast, and keeps an eye on it. By later in the day, it has settled.
That pattern fits a common, mild side effect.
Pharmacist’s tip
Take note of timing. If your back pain starts the next day rather than straight after the tablet, that can still fit with tadalafil’s known pattern.
Which side effects are common and which are urgent
Most tadalafil 5mg side effects are more annoying than dangerous. A few are serious enough that you shouldn’t “wait and see”.
The NHS says serious side effects are rare and happen in fewer than 1 in 1,000 people taking tadalafil [2].
Common and usually mild
These are the ones that can often be monitored at home, unless they become severe or keep coming back:
- Headache
- Indigestion
- Back pain
- Muscle aches
- Flushing
- Blocked nose
Urgent same-day help
Get urgent medical help if you develop:
- Chest pain
- A seizure
- Signs of a serious allergic reaction
- Sudden loss of vision
- Sudden loss of hearing
Priapism and prolonged erection
This is the one people feel embarrassed asking about, but it’s important. The NHS says to go to A&E if you get an erection that lasts more than 3 to 4 hours [2].
That may sound earlier than some leaflets you’ve seen elsewhere. Follow the NHS urgent advice in the UK.
| Symptom | What to do |
| Mild headache, flushing, indigestion | Monitor, rest, hydrate, ask a pharmacist if needed |
| Ongoing or troublesome side effects | Contact your prescriber or pharmacist |
| Chest pain, sudden vision or hearing loss | Seek urgent medical help straight away |
| Erection lasting more than 3 to 4 hours | Go to A&E urgently |
Featured snippet answer
When should I seek urgent help for tadalafil side effects?
Get urgent help for chest pain, sudden vision or hearing loss, a seizure, signs of a serious allergic reaction, or an erection lasting more than 3 to 4 hours according to NHS advice [2].
Headache after tadalafil 5mg
Headache is the side effect people mention most often. It’s also one of the best understood.
In the study mentioned earlier, 13 out of 80 men (16.25%) reported headache on daily tadalafil 5mg [1]. NHS guidance also lists headache as a common side effect.
Why the headache happens
The likely reason is cerebral vasodilation, which means blood vessels in and around the head widen [3]. That can create a pressure-type headache.
For many people, it’s mild. It often improves as the body gets used to the medicine.
What you can do
Try simple steps first:
- Drink water, especially if you’ve also had alcohol or a poor night’s sleep
- Eat normally, rather than taking the tablet on an empty stomach if that doesn’t suit you
- Rest if needed
- Use over-the-counter pain relief if it’s safe for you, such as paracetamol
When it needs a review
Speak to a pharmacist or prescriber if:
- the headache is strong
- it keeps happening
- it feels different from your usual headaches
- you also feel faint, very unwell, or have chest symptoms
Pharmacist’s tip
Don’t keep pushing through repeated headaches without asking for advice. A dose, interaction, dehydration issue, or another cause may need checking.
Back pain and muscle aches
People often find this side effect the most surprising. You take a tablet for erections and then your lower back complains the next day.
That doesn’t mean you’ve pulled a muscle at the gym. Back pain and muscle aches are recognised tadalafil side effects [2], [3].
What it tends to feel like
It’s often:
- a dull ache
- felt in the lower back
- sometimes paired with a general muscle soreness
- more noticeable later after dosing, rather than immediately
In the daily 5mg study, lower back pain affected 11 out of 80 patients (13.75%), and myalgia affected 3 out of 80 (3.75%) [1].
Why it happens
These effects are caused by the medicine’s wider effects on smooth muscle and related tissues [3]. You don’t need to memorise the chemistry. The practical point is this. It’s a known medicine effect, not necessarily a separate injury.
Real-life example 2
A gym-goer starts tadalafil 5mg and notices a lower back ache the morning after leg day. He assumes he overdid his deadlifts. But the ache appears again on a rest day after his next dose.
That repeat pattern suggests the medicine may be playing a part.
A side effect doesn’t always start right after the tablet. With tadalafil, some aches turn up later.
Pharmacist’s tip
Keep a simple symptom diary for a week. Note when you took the tablet, when the ache started, and whether it happened on training days and rest days. Patterns help prescribers.
Indigestion, reflux, and stomach upset
Some people don’t get a headache at all. Instead, they get heartburn, burping, or a heavy upper-stomach feeling.
Indigestion is listed as a common tadalafil side effect [2]. In the daily 5mg study, dyspepsia affected 8 out of 80 patients (10%), and gastro-oesophageal reflux affected 4 out of 80 (5%) [1].
Why the stomach can react
Tadalafil can relax smooth muscle, including the area involved in keeping stomach acid where it belongs [2]. That can lead to:
- indigestion
- reflux
- nausea-like discomfort
- bloating after meals
Simple ways to ease it
These often help:
- Eat smaller meals
- Avoid very heavy or spicy meals close to your dose
- Stay upright after eating
- Use an antacid if appropriate for you
If you already get frequent reflux, it’s worth mentioning that before you start.
Can tadalafil 5mg cause indigestion?
Yes. Indigestion is a common tadalafil side effect, and reflux was also reported in a daily 5mg study.
Flushing and a blocked nose
These side effects are common, but many people don’t realise they’re linked to the same blood vessel changes that help the medicine work.
You might notice your face feels warm, your cheeks look red, or your nose feels more blocked than usual. Flushing and nasal congestion are among common side effects for tadalafil.
Why these happen
When blood vessels widen:
- the skin of the face can look more flushed
- the lining of the nose can swell a little, which makes breathing through the nose feel stuffy
These effects are usually mild. They can be annoying, especially at night, but they often settle.
A practical example
A shift worker takes tadalafil 5mg before sleeping after a night shift. He isn’t worried about pain, but he notices his nose feels blocked and he breathes through his mouth more than usual. That can still fit a common side effect pattern.
Interactions and who needs extra caution
Safety holds the greatest importance. Sometimes the side effect isn’t just about tadalafil itself. It’s about what it’s mixed with.
Nitrates are a major red flag
You must not take tadalafil with nitrates. The MHRA-approved leaflet warns about this because the combination can cause a dangerous blood pressure drop [2].
Examples include medicines used for angina such as glyceryl trinitrate and similar nitrate treatments.
Alpha-blockers and other blood pressure effects
The verified data also notes extra care with alpha-blockers, because combining them can increase the chance of low blood pressure. The NHS source specifically highlights that interactions can heighten risks [2].
That doesn’t mean every blood pressure medicine is automatically incompatible. It does mean your prescriber should review your medicines list properly.
Tell your prescriber if you have
- heart or circulation problems
- low blood pressure
- a history of chest pain
- eye or hearing problems
- previous serious reactions to erectile dysfunction medicines
Pharmacist’s tip
Never leave medicines off your online questionnaire because they feel unrelated. Your nose spray, angina tablets, prostate medicine, or antifungal can matter.
Rare but serious tadalafil 5mg side effects
Individuals taking tadalafil 5mg typically won’t experience a severe reaction. Still, you should know the warning signs.
The serious side effects happen in fewer than 1 in 1,000 people [2]. That’s reassuring, but rare doesn’t mean impossible.
Priapism
A prolonged erection is a medical emergency. NHS urgent advice says go to A&E if it lasts more than 3 to 4 hours [2].
The reason is simple. A long-lasting erection can damage tissue if it isn’t treated quickly.
Vision and hearing changes
Stop taking the medicine and seek urgent help if you get:
- sudden loss of vision
- sudden loss of hearing
The MHRA-approved information also warns about serious eye problems including non-arteritic anterior ischaemic optic neuropathy, often shortened to NAION, though the frequency is not known [2]. In everyday terms, that means a rare but serious optic nerve problem.
Chest pain and severe allergic symptoms
If you develop chest pain or symptoms that suggest a severe allergic reaction, such as swelling or breathing difficulty, get urgent medical help [2].
If a symptom feels dramatic, sudden, or frightening, don’t try to diagnose it from a search result. Get help.
What to do if you get side effects
A lot of people swing between two extremes. They either ignore side effects completely, or they stop treatment after the first mild symptom.
A better approach is somewhere in the middle.
If the side effect is mild
You can often try simple measures:
- Hydrate well
- Avoid heavy meals if you’re getting indigestion
- Use simple over-the-counter remedies if they’re safe for you
- Monitor the timing and pattern
- Ask a pharmacist if you’re unsure
The verified data notes practical measures such as hydration, antacids, or over-the-counter pain relief for manageable side effects.
If the side effect keeps coming back
Book a review if:
- symptoms are stopping you from carrying on normally
- they don’t settle
- they seem linked to another medicine
- you’re tempted to change the dose yourself
Don’t increase, split, or stop prescribed treatment without advice from a clinician who knows your medical history.
Reporting side effects in the UK
The MHRA-approved leaflet also points patients towards Yellow Card reporting for side effects. That can help monitor medicine safety in the UK.
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Questions people often ask in the pharmacy
Does tadalafil 5mg side effects mean the medicine isn’t right for me
Not necessarily. Mild side effects can happen even when the medicine is suitable. The question is how strong they are, how long they last, and whether they create any safety concern.
Are daily 5mg side effects different from occasional use
They can feel different because daily dosing creates a more regular medicine level in your body. In practice, some people notice mild side effects early on and then find they settle with time.
Is it normal to feel fine at first and then get side effects later
Yes, especially for back pain and muscle aches, which can appear 12 to 24 hours after dosing.
Can I just stop taking tadalafil if I get a headache
You can pause and seek advice, but don’t make repeated changes without discussing it with your prescriber. A headache may settle with simple measures or may point to a timing or interaction issue.
Summary
Tadalafil 5mg side effects are usually mild and manageable. The most common ones are headache, indigestion, back pain, muscle aches, flushing, and nasal congestion. In a daily 5mg study, headache was the most frequently reported side effect, and the reported effects were generally mild, with no discontinuations [1].
The key is knowing what’s expected and what needs urgent action. Seek urgent help for chest pain, sudden vision or hearing loss, or an erection lasting more than 3 to 4 hours.
If you’re getting side effects that are persistent, bothersome, or confusing, speak to a pharmacist or prescriber. You don’t need to guess your way through it.
FAQs
Is tadalafil 5mg safe for daily use?
For many people, yes, if a clinician has checked it’s suitable. In the study cited above, daily 5mg tadalafil was generally well tolerated, with mild side effects and no discontinuations. Safety depends on your health history and other medicines.
What is the most common side effect of tadalafil 5mg?
Headache is the most commonly reported side effect in the clinical study provided, affecting 13 out of 80 patients (16.25%) [1]. The NHS also lists headache as a common side effect.
Can tadalafil 5mg cause back pain?
Yes. Back pain is a recognised tadalafil side effect in both NHS and MHRA-approved information. In the daily 5mg study, 11 out of 80 patients (13.75%) reported lower back pain [1].
How long do tadalafil 5mg side effects last?
Many mild side effects settle on their own. Because tadalafil has a long half-life of about 17.5 hours, some effects can appear later and may take time to wear off. If symptoms are severe or persistent, seek advice.
Can tadalafil 5mg cause indigestion every day?
It can cause indigestion in some people, especially with daily dosing. If it keeps happening, speak to your prescriber. Small meals and antacids may help if they’re suitable for you.
When should I go to A&E after taking tadalafil?
Go to A&E if you have an erection lasting more than 3 to 4 hours according to NHS urgent advice. Also seek urgent help for chest pain, sudden vision loss, sudden hearing loss, seizures, or severe allergic symptoms.
Can I take paracetamol with tadalafil for a headache?
The verified data notes paracetamol as a practical option for headache relief. Still, check that it’s suitable for you, especially if you have other health conditions or take other medicines.
Do side effects mean tadalafil is working?
Not always. Some people get benefits with no side effects at all. Side effects show the medicine is having effects in the body, but they don’t reliably measure how well it’s working for erections.
Should I stop tadalafil 5mg if I get a blocked nose or flushing?
Not usually, if the symptom is mild and settles. Those are recognised common side effects. If they’re strong, persistent, or come with dizziness or other worrying symptoms, get advice.
How this content was created
This article was written using verified UK patient information, MHRA-approved medicine guidance, and a peer-reviewed clinical study. A clinician-reviewed editorial process checked the content for clarity, safety, and UK relevance. This article is for information only and isn’t a substitute for personal medical advice.
If you want a regulated online route to treatment review, Courier Pharmacy offers UK-based prescribing and follow-up support.
Disclaimer: This information is for education only and isn’t a substitute for personal medical advice. Always follow your prescriber’s instructions.
References
[2] Medicines.org.uk (MHRA-approved patient leaflet) (n.d.) Tadalafil 5 mg film-coated tablets patient information leaflet. Available at: https://www.medicines.org.uk/emc/files/pil.15261.pdf
[3] Courier Pharmacy (2026) Comprehensive literature review: Side effects of tadalafil and PDE5 inhibitor selectivity. Courier Pharmacy. Available at: https://courierpharmacy.co.uk/comprehensive-literature-review-side-effects-of-tadalafil-and-pde5-inhibitor-selectivity/ (Accessed: 4 June 2026).
