Can you combine ED medicines? What the labels and the AUA say

In short: the four FDA-approved ED pills, sildenafil (Viagra), tadalafil (Cialis), vardenafil and avanafil (Stendra), carry nearly the same warning: using one with another ED medicine or ED treatment has not been studied. Three labels call the combination not recommended, and the tadalafil label tells prescribers to inform patients not to take it with other PDE5 inhibitors. Sildenafil’s label adds the reason in plain terms: such combinations may lower blood pressure further (Viagra prescribing information, DailyMed). That does not mean ED treatment is always one thing at a time. The American Urological Association (AUA) guideline statements do describe one pairing, a PDE5 inhibitor with testosterone therapy, for men whose testosterone is confirmed low (AUA erectile dysfunction guideline). This page sets out what the labels, the guideline, FDA and the published studies say, so the question can go to a prescriber with the facts attached. Evidence level: label warnings plus a small number of small trials; the labels state that the safety and effectiveness of these combinations have not been studied.

Can you take sildenafil and tadalafil together?

Not on your own, and not as a do-it-yourself fix. Both labels say the combination has not been studied for safety or effectiveness: the Viagra label says combining it with other PDE5 inhibitors or other ED treatments “is not recommended,” and the Cialis label tells prescribers to inform patients not to take it with other PDE5 inhibitors (Viagra prescribing information, DailyMed; Cialis prescribing information, DailyMed). Sildenafil and tadalafil work the same way, by blocking the PDE5 enzyme, so taking both adds a second drug to the same job rather than a different kind of help.

A few small trials have tested the pair under a doctor’s supervision, covered further down. They do not change what the labels say, and they are not a reason to combine pills from two different prescriptions or sources.

What do the labels say about combining ED treatments?

All four labels give the same core answer: not studied. Three say the combination is not recommended, and the Cialis label tells prescribers to inform patients not to take it with other PDE5 inhibitors.

Sources: Viagra prescribing information; Cialis prescribing information, revised 2026; vardenafil hydrochloride tablets prescribing information, Lannett; Stendra prescribing information, all on DailyMed.

The patient leaflets say the same thing in everyday language. Each lists “other medicines or treatments for ED” among the things to tell your healthcare provider about, and the Cialis leaflet says directly not to use other ED medicines or ED treatments while taking Cialis. The same drugs are also sold under other names for a lung condition, pulmonary arterial hypertension: sildenafil as Revatio and tadalafil as Adcirca. The Viagra and Cialis labels say not to take those pills together with these, which matters for men who might not realize they already take a PDE5 inhibitor under another name.

Why do the labels advise against combining ED medicines?

Two reasons come straight from the labels: the combinations have not been studied, and, in the Viagra label’s words, they may further lower blood pressure (Viagra prescribing information, DailyMed). Each label describes its drug as having mild blood-vessel-widening (vasodilatory) effects, and the labels also flag alpha blockers and other blood pressure medicines; the Cialis and Stendra labels add heavy drinking. The most serious version of this is the combination with nitrate heart medicines or “poppers,” which all four labels forbid; our guide to nitrates and ED medicines explains that rule in full.

The labels also list a rare but urgent risk for every drug in the class: an erection lasting longer than 4 hours. The Viagra label says to seek immediate medical help if that happens, because untreated priapism can cause permanent damage (Viagra prescribing information, DailyMed). No label puts a number on whether combining drugs raises that risk, because the combinations were not studied. Our page on priapism covers what to do if it happens.

There is also a practical reason. Each label sets its own rules for dose changes when a man takes certain antifungals, antibiotics, HIV medicines or blood pressure medicines. Those rules were written for one PDE5 inhibitor at a time. Our pages on sildenafil interactions and tadalafil interactions list them drug by drug.

Has any study tested sildenafil and tadalafil together?

Yes, but only a few small studies, and they are not enough to change the label advice. In one trial from China, 180 men with ED were split between daily tadalafil alone and daily tadalafil with sildenafil added as needed. Men with severe ED scored higher on an erectile-function questionnaire with the combination, and the rate of side effects did not differ between the groups (Cui et al., Andrologia 2015). A 2019 systematic review of studies in men who had not responded to a single PDE5 inhibitor reached a more cautious reading: daily tadalafil alone and daily tadalafil with sildenafil as needed produced similar score improvements (Munk et al., Sex Med Rev 2019).

A larger 2021 meta-analysis included 44 studies of 3,853 men comparing combination treatment with a single first-line ED treatment, most often a PDE5 inhibitor plus another agent. Adding daily tadalafil was linked to a modest improvement in scores, but that result rested on a single study, and the authors noted high variation between studies throughout (Mykoniatis et al., JAMA Netw Open 2021). All of these combinations were given inside clinical studies, under medical supervision.

Are sildenafil and tadalafil combination tablets FDA-approved?

Status: Compounded: not FDA-approved. Source: Drugs@FDA and FDA, Compounding and the FDA: Questions and Answers, checked 2026-10-17.

No. Drugs@FDA, the agency’s database of approved drugs, lists no product that combines sildenafil and tadalafil (Drugs@FDA). The only approved products that pair tadalafil with another drug treat other conditions: Entadfi, finasteride with tadalafil, for the signs and symptoms of an enlarged prostate (benign prostatic hyperplasia), and Opsynvi, macitentan with tadalafil, for pulmonary arterial hypertension (Entadfi prescribing information; Opsynvi prescribing information, DailyMed). Neither is approved for ED.

That means a tablet, troche or “combo” product containing both sildenafil and tadalafil is either made by a compounding pharmacy or sold outside the legal system. FDA states plainly that compounded drugs are not FDA-approved, so the agency does not verify their safety, effectiveness or quality before they are sold. FDA also says compounded drugs should only be used when a patient’s needs cannot be met by an FDA-approved drug, and that poor compounding can produce a drug with too much or too little of the active ingredient (FDA, Compounding and the FDA: Questions and Answers). If a service offers a combination product, it is fair to ask why an approved single medicine would not meet your needs.

Can a supplement contain both sildenafil and tadalafil?

Yes, and FDA has found exactly that. In one notice, FDA laboratory testing confirmed that a product sold for sexual enhancement, Triple SupremeZen Extreme 3500, bought from Amazon, contained both sildenafil and tadalafil without listing them. FDA warned that the hidden ingredients may interact with nitrates and lower blood pressure to dangerous levels (FDA public notification, December 2020). A man who takes a prescribed ED pill and one of these products could be combining drugs without knowing it. Our page on FDA warnings about tainted supplements explains how these products are found and how to check one.

Where does testosterone therapy fit?

Testosterone is the one add-on the AUA guideline statements name, and only for men with ED whose testosterone is confirmed low. The guideline says morning total testosterone should be measured in men with ED, and that men with testosterone deficiency who are considering a PDE5 inhibitor should be told the pill may work better combined with testosterone therapy. It rates that statement a moderate recommendation backed by lower-certainty (Grade C) evidence (AUA erectile dysfunction guideline).

The trial data are mixed. The 2021 meta-analysis found that combination treatment was linked to a modest improvement in scores in men with low testosterone (Mykoniatis et al., JAMA Netw Open 2021), while the 2019 review found that none of 3 randomized trials in men who had not responded to a PDE5 inhibitor showed a better effect from adding androgen (male hormone) therapy, though the pairing appeared safe (Munk et al., Sex Med Rev 2019). Testosterone is a prescription treatment that starts with blood tests, not a booster to add on a hunch. Our page on ED and low testosterone covers testing and what treatment involves.

What about PT-141?

PT-141, generic name bremelanotide, is not approved for men in the US. It is sold as Vyleesi, an injection approved only for premenopausal women with a specific low-desire condition, and the label’s limitations of use state it is not indicated for that condition in men (Vyleesi prescribing information, DailyMed). The same label reports that each dose temporarily raises blood pressure and lowers heart rate, usually returning to baseline within 12 hours, which is worth knowing before mixing it with anything that also affects blood pressure.

The published evidence on PT-141 with sildenafil is thin. In one crossover trial of 19 men who already responded to an ED pill, run by the company then developing the drug, a nasal form of PT-141 given with sildenafil produced a greater erectile response in the lab than sildenafil alone, with no new side effects reported (Diamond et al., Urology 2005). That single short study is not evidence of safety for everyday use, and products sold online as “PT-141” are not the approved drug. Our page on PT-141 for men covers the rest of the evidence.

What if one ED medicine is not working?

Talk to the prescriber before reaching for a second pill. The AUA guideline says men should get clear instructions on how to take a PDE5 inhibitor to get the most from it, and that the dose should be adjusted to find what works, both strong recommendations (AUA erectile dysfunction guideline). A prescriber may also check for causes such as low testosterone, or move to a different medicine or a treatment that is not a pill. Our guide to why sildenafil may not be working walks through the common reasons, and changing the dose is always the prescriber’s call.

When should you talk to a clinician about combining treatments?

Before adding any second ED medicine, product or treatment, and whenever a new prescription is started elsewhere. The patient leaflets ask men to tell their healthcare provider about other medicines or treatments for ED, and the Viagra leaflet asks them to keep a list of everything they take to show prescribers and pharmacists (Viagra prescribing information, DailyMed). Bring that list, including any supplements, PT-141, testosterone or pills from another online service, so one person can see the whole picture.

Sources

1. Viagra (sildenafil citrate) prescribing information, Pfizer, DailyMed
2. Cialis (tadalafil) prescribing information, Eli Lilly and Company, DailyMed
3. Vardenafil hydrochloride tablets prescribing information, Lannett Company, DailyMed
4. Stendra (avanafil) prescribing information, Metuchen Pharmaceuticals, DailyMed
5. American Urological Association. Erectile Dysfunction: AUA Guideline (2018)
6. U.S. Food and Drug Administration. Compounding and the FDA: Questions and Answers
7. U.S. Food and Drug Administration. Drugs@FDA database
8. Entadfi (finasteride and tadalafil) prescribing information, DailyMed
9. Opsynvi (macitentan and tadalafil) prescribing information, DailyMed
10. U.S. Food and Drug Administration. Public Notification: Triple SupremeZen Extreme 3500 contains hidden drug ingredients
11. Vyleesi (bremelanotide injection) prescribing information, DailyMed
12. Diamond LE, et al. Co-administration of low doses of intranasal PT-141 and sildenafil to men with erectile dysfunction. Urology. 2005
13. Cui H, et al. Efficacy and safety of long-term tadalafil once daily combined with sildenafil as needed at the early stage of treatment for erectile dysfunction. Andrologia. 2015
14. Munk NE, et al. Systematic review of oral combination therapy for erectile dysfunction when phosphodiesterase type 5 inhibitor monotherapy fails. Sex Med Rev. 2019
15. Mykoniatis I, et al. Assessment of combination therapies vs monotherapy for erectile dysfunction: a systematic review and meta-analysis. JAMA Netw Open. 2021