Oral Medications (PDE-5 Inhibitors)
The first-line treatment for erectile dysfunction (ED) consists of medications known as phosphodiesterase type 5 (PDE-5) inhibitors. These drugs enhance the natural erectile response by increasing blood flow to the penis during sexual stimulation.
Important: These medications do not automatically cause an erection. Sexual arousal is still required.
Available PDE-5 Inhibitors
Generic Name | Europe (Common Brands) | United States | India (Common Brands) |
Sildenafil | Viagra®, Sildenafil Generics | Viagra®, Revatio® | Suhagra®, Penegra®, Caverta®, Zenegra® |
Tadalafil | Cialis®, Tadalafil Generics | Cialis®, Adcirca® | Megalis®, Tadalis®, Tazzle® |
Vardenafil | Levitra®, Vivanza® | Levitra®, Staxyn® | Valif®, Zhewitra®, Vilitra® |
Avanafil | Spedra® | Stendra® | Avana®, Avaforce® |
Comparison of Available Medications
Medication | Time to Onset | Duration of Effect | Food Effect | Best Use |
Sildenafil | 30–60 min | 4–6 hours | High-fat meals may delay effect | Occasional planned intercourse |
Tadalafil | 20–40 min | Up to 36 hours | Minimal food effect | Greater spontaneity |
Vardenafil | 25–60 min | 4–6 hours | Food may slightly delay effect | Similar to sildenafil |
Avanafil | 15–30 min | 6–8 hours | Minimal food effect | Rapid onset |
Why Tadalafil Is Different
Tadalafil is often called the “weekend pill” because its effects may last up to 36 hours. This does not mean a continuous erection occurs; rather, the ability to achieve an erection during sexual stimulation is enhanced during this period.
Daily Tadalafil
For men who are sexually active more frequently, tadalafil can also be prescribed as a daily low-dose treatment.
Dose | Typical Use |
2.5 mg daily | Mild ED |
5 mg daily | ED and/or enlarged prostate (BPH) |
Advantages:
Expected Success Rates
Success rates vary depending on the underlying cause of erectile dysfunction.
Cause of ED | Expected Response Rate |
Psychological causes | 70–90% |
Mild vascular disease | 70–80% |
Diabetes without severe complications | 50–70% |
Long-standing diabetes with neuropathy | 30–60% |
After radical prostatectomy | 20–50% |
Men with diabetes often require higher doses than men without diabetes.
Common Side Effects
All PDE-5 inhibitors share similar side effects because they act on blood vessels throughout the body.
Side Effect | Sildenafil | Tadalafil | Vardenafil | Avanafil |
Headache | Common | Common | Common | Common |
Facial flushing | Common | Common | Common | Less common |
Nasal congestion | Common | Common | Common | Less common |
Heartburn | Common | Common | Common | Less common |
Dizziness | Occasionally | Occasionally | Occasionally | Occasionally |
Back pain | Rare | More common | Rare | Rare |
Muscle aches | Rare | More common | Rare | Rare |
Blue-tinted vision | Possible | Rare | Possible | Rare |
Who Should NOT Take PDE-5 Inhibitors?
Absolute Contraindications
These medications must never be combined with nitrate-containing drugs because severe, potentially life-threatening hypotension can occur.
Examples include:
Nitrate Medication | Common Use |
Nitroglycerin (Nitrolingual®) | Angina |
Isosorbide dinitrate (ISDN) | Angina |
Isosorbide mononitrate (ISMN) | Angina |
Molsidomine | Angina |
Use With Caution In:
A cardiovascular assessment may be necessary before treatment is prescribed.
Erectile Dysfunction as a Cardiovascular Warning Sign
In many men, erectile dysfunction develops 3–5 years before symptoms of coronary artery disease become apparent. Because penile arteries are smaller than coronary arteries, vascular damage often appears there first.
For this reason, new-onset erectile dysfunction—particularly in men with diabetes—should be considered a possible early warning sign of:
Beware of Unregulated “Potency Enhancers”
Many products marketed online as “natural” sexual enhancers contain:
Patients should use only medications prescribed by a qualified healthcare professional and obtained from licensed pharmacies.
Vacuum erection devices create an erection without medication by generating negative pressure around the penis. This draws blood into the erectile tissue, causing an erection.
Effectiveness
Possible Side Effects
Vacuum pumps may be particularly useful when medications are not desired or cannot be tolerated.
How They Work
The penis is placed inside a clear plastic cylinder. A small motor creates a vacuum that draws blood into the erectile tissue. The desired erection is usually achieved within about 30 seconds.
After removing the pump, a rubber constriction ring is placed at the base of the penis to prevent blood from flowing out. Following intercourse, the ring is removed and the erection subsides. The ring should not remain in place for longer than 30 minutes.
With ICI an erection-inducing medication is injected directly into the erectile tissue before sexual activity.
Because very fine needles are used, the injection is usually nearly painless.
Effectiveness
The dose must be carefully adjusted under medical supervision, and alcohol should be avoided during use.
Side Effects
An excessively high dose can cause priapism (a prolonged, painful erection). If this occurs, immediate medical attention—preferably from a urologist—is required.
How the Medication Works
The injected drug contains alprostadil, a synthetic form of prostaglandin E1. It relaxes the muscles of the penile arteries, allowing blood vessels to widen and blood to flow into the erectile tissue, producing an erection.
MUSE also uses alprostadil, but instead of an injection, the medication is inserted into the urethra using a thin applicator.
The drug is absorbed through the urethral lining and usually begins working within 5–10 minutes. However, erections are generally less reliable than with ICI.
Important Considerations
Today MUSE is mainly considered for men who:
Current Position in Urology
In modern international guidelines, the treatment hierarchy is typically:
Many urologists now use ICI (intracavernosal injection therapy) more often than MUSE because efficacy is generally higher. One comparative study reported substantially better erection rates with intracavernosal alprostadil than with MUSE.
If all other treatment options fail, surgical implantation of a penile prosthesis may be considered.
Most modern implants are hydraulic, inflatable systems consisting of:
The implant is typically inserted through an incision beneath the penis, leaving little or no visible scarring. When an erection is desired, the pump transfers fluid into the cylinders. Activating a release valve allows the erection to subside.