ED Pill Headache and Back Pain: Viagra and Cialis Label Rates
ED pill headache and back pain, from the Viagra and Cialis labels: how often each happens, why it rises with strength, when Cialis back pain starts and ends.
By Julian Caraulani · Last updated
SafetyReviewed by Dr. A. Goher, MBBS
- FDA-approved and compounded
- LegitScript seal ID shown
- 49 states (not AR)
Below: the label rates for headache and back pain by drug and strength, why they happen, how long they last, and what to do. All label figures were read on DailyMed on 14 November 2026. A dummy pill, or placebo, contains no drug. We do not give doses; the prescriber picks the strength.
Viagra headache: how common?
In trials where men took Viagra as needed, headache hit 16% of men on the drug and 4% on placebo (DailyMed: Viagra label). The label's fixed-strength trials show it rises with the tablet strength.
| Viagra fixed-strength trials | Lowest strength | Middle strength | Highest strength | Placebo |
|---|---|---|---|---|
| Headache | 16% | 21% | 28% | 7% |
| Flushing | 10% | 19% | 18% | 2% |
| Back pain | 3% | 4% | 4% | 2% |
Source: Viagra label, Table 1, read 14 November 2026. Flushing means a warm, red face, and it often comes with the headache.
Cialis headache and tadalafil headache
Tadalafil shows the same pattern. In the label's eight trials of as-needed use, headache rose with strength.
| Cialis trials | Placebo | Lowest strength | Middle strength | Highest strength |
|---|---|---|---|---|
| Headache, as needed | 5% | 11% | 11% | 15% |
| Back pain, as needed | 3% | 3% | 5% | 6% |
| Muscle aches, as needed | 1% | 1% | 4% | 3% |
| Pain in limb, as needed | 1% | 1% | 3% | 3% |
Source: Cialis label, Table 1, read 14 November 2026.
Daily tadalafil is a lower strength, and headache rates were much lower. In the daily trials for ED, headache was 3% and 6% at the two daily strengths, against 5% on placebo. In the daily trials for an enlarged prostate, it was 4.1% against 2.3% (DailyMed: Cialis label). Our daily tadalafil cost guide covers that option.
- FDA-approved and compounded
- LegitScript seal ID shown
- 49 states (not AR)
Why ED pills cause headaches
Both drugs widen blood vessels. That is how they help an erection, but it happens in other places too, including the head and face. The Cialis label calls PDE5 inhibitors "mild vasodilators", which means they widen blood vessels. Wider vessels in the head can bring a throbbing headache, flushing and a stuffy nose.
That is also why the rate climbs with strength. More drug means more widening, so more headaches.
How long an ED pill headache lasts
The Cialis patient leaflet says: "The most common side effects with CIALIS are: headache, indigestion, back pain, muscle aches, flushing, and stuffy or runny nose. These side effects usually go away after a few hours." (DailyMed: Cialis label).
Sildenafil leaves the body faster: its half-life is about 4 hours, against 17.5 hours for tadalafil. Half-life is the time for half of the drug to leave the blood. So a sildenafil headache tends to fade the same day. Our guides to how long Viagra lasts and how long Cialis lasts explain the timing.
Cialis back pain
Back pain is the side effect that sets tadalafil apart. Sildenafil showed back pain in 2% of men on the drug and 2% on placebo in its as-needed trials, so no real difference. Tadalafil showed 6% against 3% at its highest strength.
The Cialis label gives unusual detail. It says "back pain or myalgia generally occurred 12 to 24 hours after dosing and typically resolved within 48 hours." Myalgia means muscle aches. It describes the pain as "diffuse bilateral lower lumbar, gluteal, thigh, or thoracolumbar muscular discomfort" that "was exacerbated by recumbency" (DailyMed: Cialis label). In plain words: a spread-out ache in the muscles of the lower back, buttocks and thighs, on both sides, worse when lying down.
The label adds that it was "mild or moderate in severity and resolved without medical treatment" in most cases. About 0.5% of men stopped Cialis because of it. The label does not explain why tadalafil causes it.
What helps, and when to call
The label reports that when men in the trials needed something for back pain, "acetaminophen or non-steroidal anti-inflammatory drugs were generally effective" (DailyMed: Cialis label). Ask your pharmacist or prescriber before taking any painkiller with an ED pill, especially if you have heart, kidney or stomach problems.
MedlinePlus, the US National Library of Medicine's drug guide, says to tell your doctor if a headache is "severe or do not go away" (MedlinePlus: sildenafil, read 14 November 2026). A prescriber can lower the strength or switch drugs. A pooled study of 72 trials found sildenafil had the highest overall side effect rate of the ED pills it compared, and tadalafil "had the lowest overall rate of all adverse events" (Chen et al., Eur Urol 2015, PubMed). Adverse events means side effects.
Get urgent care for chest pain, fainting, sudden vision or hearing loss, or an erection that lasts more than 4 hours. Our ED pill side effects guide lists every label warning.
Switching strength or drug: what it costs
Programs price each drug and strength separately, so a switch can change the bill. The table is ranked on our score, with prices from each seller's own page, as checked November 14, 2026.
| Program | Generic sildenafil, per dose | Generic tadalafil, per dose |
|---|---|---|
| Ro | $4 | $11 |
| Rex MD | $1.80 | $6 |
| Strut Health | $1.60 | $2.40 |
| Hims | $4 | $6 |
| Idun Rx | $6 | $6 |
Every strength and pack is on our sildenafil price page and tadalafil price page. Every program is ranked on Best online ED programs.
Questions
FAQ
Do ED pills cause headaches?
Yes, often. Headache is the most common side effect on both labels: 16% of men on Viagra against 4% on placebo in as-needed trials, and up to 15% on Cialis against 5%. Rates rise with tablet strength. The Cialis leaflet says these side effects usually go away after a few hours.
Why does Cialis give me a headache?
Tadalafil widens blood vessels, which is how it helps erections, and it does the same in the head. The Cialis label calls the drug class mild vasodilators. Headache rates rose from 11% to 15% across strengths in as-needed trials, against 5% on placebo. A lower strength or daily use may cause fewer.
How long does a Viagra headache last?
Sildenafil has a half-life of about 4 hours, so most of it leaves the body within the day, and headaches usually fade with it. The label does not give a set duration. MedlinePlus says to tell your doctor if a headache is severe or does not go away.
What does tadalafil back pain feel like?
The Cialis label describes a spread-out muscle ache in the lower back, buttocks and thighs, on both sides, often worse when lying down. It usually began 12 to 24 hours after a dose and went away within 48 hours. Most cases were mild or moderate and needed no treatment.
Does Viagra cause back pain?
Rarely, in a way that stands out. In the label's as-needed trials, back pain hit 2% of men on Viagra and 2% on placebo. Fixed-strength trials showed 3% to 4% against 2%. Back pain is much more typical of tadalafil, which showed up to 6% against 3%.
Can I take a painkiller for an ED pill headache?
The Cialis label reports that acetaminophen or anti-inflammatory painkillers generally helped back pain in its trials. Ask a pharmacist or your prescriber first, because some painkillers do not suit people with heart, kidney or stomach problems. If headaches keep coming, ask about a lower strength or another drug.
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