If you’ve noticed a burning feeling in your chest a few hours after taking Cialis or Viagra, you’re not imagining it. Heartburn and indigestion rank among the more common side effects of erectile dysfunction (ED) medications. For some men, the discomfort is bad enough that they think about giving up on treatment altogether.
Dr. David Josephson of Tower Urology in Los Angeles explains why these medications can trigger reflux, why Cialis seems to cause it more often, and what you can do to keep heartburn from standing between you and effective treatment.
Why do ED medications cause heartburn?
Cialis (tadalafil) and Viagra (sildenafil) belong to a group of drugs called phosphodiesterase type 5 (PDE5) inhibitors. They improve erections by relaxing the smooth muscle in the blood vessels of the penis so more blood can flow in. Smooth muscle isn’t found only in the penis, though. It also lines your digestive tract, including your esophagus.
The valve that keeps acid down
“A ring of muscle where your food pipe meets your stomach acts like a valve, helping keep stomach contents from coming back up,” says Dr. Josephson. Doctors call this ring the lower esophageal sphincter (LES). When it stays tightly closed, acid stays where it belongs.
“These medicines relax smooth muscle,” Dr. Josephson explains. “That helps them do their job, but they can also relax this valve and weaken the squeezing action of the food pipe. This may make it easier for acid to move upward and harder to clear it away, causing burning or a sour taste.”
What the research shows
Researchers have measured this effect directly. In a study published in the journal Gut, six healthy men who took 50 mg of Viagra had lower pressure in the lower esophageal sphincter and weaker esophageal contractions than when they took a placebo. In the four volunteers who were monitored longer, the effect lasted at least eight hours.
A 2023 systematic review in BMC Gastroenterology pooled 14 studies on sildenafil, tadalafil, and vardenafil. The authors concluded that PDE5 inhibitors “significantly reduce LES resting pressure and esophageal peristaltic vigor.” In other words, the valve gets looser, and the esophagus pushes food and acid down less forcefully.
That same muscle-relaxing effect is why gastroenterologists have studied these drugs as a possible treatment for esophageal spasm disorders. In a man whose esophagus works normally, a looser valve can mean reflux.
Is Cialis more likely to cause reflux than Viagra?
“Not everyone gets reflux,” Dr. Josephson says. “Cialis is longer acting than Viagra, and some research suggests reflux is reported more often with Cialis, although your experience may differ.”
The difference in how long each drug stays in your system is large. Tadalafil has a half-life of about 17.5 hours, compared with roughly four hours for sildenafil, and it can keep working for up to 36 hours. That long window gives you more flexibility on timing. It also means your esophageal valve may stay relaxed for longer.
A large study published in European Urology Focus looked at patient-reported outcomes from about 130,000 men who got ED medication through a direct-to-consumer telehealth platform. Reflux was reported by 8.0% of men taking tadalafil and 5.3% of men taking sildenafil, a statistically significant difference. Because the data came from patients’ own reports rather than a controlled trial, it shows a pattern, not proof of cause.
Side effect rates from clinical trials
Both drugs list digestive side effects in their FDA prescribing information. The numbers rise with the dose.
- In as-needed Cialis trials, indigestion affected 8% of men on 10 mg and 10% of men on 20 mg, compared with 1% on placebo. In daily-use trials, 2-3% of men on 2.5 mg or 5 mg reported reflux, compared with 0% on placebo.
- In flexible-dose Viagra trials, indigestion affected 7% of men, compared with 2% on placebo. At a fixed 100 mg dose, the rate climbed to 17%.
How to ease reflux while taking ED medication
For many men, a few habit changes are enough. “To help, avoid foods and drinks that trigger your symptoms and wait at least three hours after eating before lying down,” Dr. Josephson recommends.
Common reflux triggers include:
- Fried and fatty foods
- Spicy dishes
- Tomatoes and citrus
- Chocolate and peppermint
- Coffee, alcohol, and carbonated drinks
Timing matters too. If you take Viagra or an as-needed dose of Cialis before a late dinner, you’re stacking a relaxed valve on top of a full stomach. If nighttime symptoms bother you, the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) suggests raising your head 6-8 inches with a foam wedge or extra pillows under your head and upper back.
Over-the-counter heartburn medicine
“An over-the-counter medicine like Pepcid may help,” says Dr. Josephson. “Check with your pharmacist or us that it’s appropriate for you.”
Pepcid (famotidine) is an H2 blocker, which means it lowers the amount of acid your stomach makes. Not every acid reducer behaves the same way with ED medication, which is one reason to check first. According to the Viagra prescribing information, cimetidine (Tagamet), another H2 blocker, raised blood levels of sildenafil by 56%, while a standard magnesium and aluminum hydroxide antacid had no effect on how the drug was absorbed.
Adjusting your dose or schedule
Since digestive side effects tend to increase with dose, changing how you take your medication may help. “We can also review whether a lower dose or a different dosing schedule might help,” Dr. Josephson says. “Please talk with us before changing your dose or splitting tablets.”
Cialis comes in two dosing styles. The recommended starting dose for as-needed use is 10 mg, and the starting dose for once-daily use is 2.5 mg. Some men who get heartburn from a larger as-needed dose do better on a small daily dose, and others do better switching to a shorter-acting medication. Cialis tablets also aren’t scored, so cutting them at home may not give you an even dose. Our urologists can help you find the right fit.
Other ED treatments if reflux won’t go away
Pills aren’t the only way to treat ED. “If symptoms persist, we can discuss other options for erections, including a vacuum erection device, medication placed in the urethra, or penile injections,” says Dr. Josephson.
These options are all part of the American Urological Association’s erectile dysfunction treatment guideline. Each one works locally, so none relies on a pill that relaxes muscle throughout your body.
- A vacuum erection device is a cylinder placed over the penis. A pump draws blood in, and a ring at the base holds the erection.
- Intraurethral alprostadil is a tiny, medicated pellet placed in the tip of the urethra. It directly relaxes blood vessels in the penis.
- Penile injections deliver medication into the side of the penis with a very fine needle.
For men who want a permanent solution, a penile implant is another option to discuss with our urologists.
When heartburn needs a closer look
Occasional heartburn after a dose is usually manageable. Let us know if reflux happens more than twice a week, keeps you up at night, or comes with trouble swallowing, since these can point to gastroesophageal reflux disease (GERD) that needs its own evaluation.
Chest pain deserves extra caution. It can be hard to tell heartburn from a heart problem, so call 911 if your chest pain feels severe, spreads to your arm or jaw, or comes with shortness of breath. Tell the emergency team you’ve taken an ED medication. Nitroglycerin and other nitrates can cause a dangerous drop in blood pressure when combined with these drugs, and the Cialis label states that at least 48 hours should pass after the last dose before nitrates are considered.
Find an ED treatment you can live with
Heartburn from an ED pill doesn’t have to be the end of treatment. “We have other options for you, and we can work together to find a treatment you tolerate well,” says Dr. Josephson.
Call (855) 246-2700 or request your appointment online to schedule a consultation with Dr. Josephson or one of our urologists at Tower Urology in Los Angeles.
