CIALIS vs VIAGRA
Independent side-by-side comparison.
Two PDE5 inhibitors for erectile dysfunction whose labels carry the same headline dangers. They are more alike than the internet pretends, and the choice belongs to your prescriber.
The key difference
One difference that matters is what each label is actually approved for, and how it is meant to be taken. Cialis is indicated for erectile dysfunction and also for the signs and symptoms of benign prostatic hyperplasia (BPH), including both together; its label describes an as-needed tablet and, separately, a once-daily option taken at about the same time each day without regard to timing of sexual activity. Viagra's label covers erectile dysfunction, as an as-needed tablet taken before sexual activity. Cialis's label also states that as-needed use improved erectile function versus placebo for up to 36 hours after a dose.
The shared warning that can kill is named on both labels: taking either drug with any organic nitrate is CONTRAINDICATED — they potentiate the blood-pressure-lowering effect of nitrates. Both also carry the cardiovascular warning that sexual activity itself carries cardiac risk in men with pre-existing cardiovascular disease, and neither should generally be used when sex is inadvisable for that reason.
What favours Cialis (tadalafil)
A prescriber may lean toward Cialis when BPH symptoms sit alongside the ED, since that indication is on its label and not on Viagra's, or when a once-daily rhythm suits the patient better than planning around a dose. Its label warns that combining it with alpha-blockers, other antihypertensives, or substantial amounts of alcohol can drop blood pressure, and it is not recommended with an alpha-blocker for BPH.
What favours Viagra (sildenafil)
A prescriber may stay with Viagra when the goal is erectile dysfunction alone and an as-needed tablet before sexual activity fits how the person actually lives. Its label also spells out dose reduction when a strong CYP3A4 inhibitor such as ritonavir is on board, and it directs that anyone already on an alpha-blocker be stable on it before sildenafil is started.
Bottom line
Both are PDE5 inhibitors; both are contraindicated with nitrates in any form and with guanylate cyclase stimulators such as riociguat; both labels tell the patient to seek emergency care for an erection lasting more than four hours, and to stop the drug and get medical attention for sudden vision loss (a possible sign of NAION) or sudden loss of hearing. Neither is safe to buy from a site that will sell it without asking about your heart or your nitrates.
We don't sell these drugs and we don't sell coupons — we rate them on their FDA recall record — so we can tell you the thing a seller can't: for most men this is not a contest between two molecules, it's a conversation with a prescriber about your heart, your other medicines, and whether BPH is part of the picture. This page is not a substitute for the FDA label.
This is not a summary of either drug’s FDA label, and it is not complete. Both labels carry warnings, contraindications and interactions that are not on this page. Read the label for the drug you are actually taking — we link both above — and take the decision to your prescriber.
Possible drug interaction. CIALIS and VIAGRA are different prescription medicines. Combining or switching between them can cause interactions — talk to a pharmacist or prescriber before making changes. This page is not medical advice.
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Frequently asked questions
What is the difference between Cialis and Viagra?
Cialis contains Tadalafil, while Viagra contains Sildenafil Citrate — they have different active ingredients.
Ratings are based on FDA regulatory (recall-safety) data. This comparison is for general reference only — not medical advice. Always consult a licensed professional before choosing or switching a medication.