Four popular drugs are widely available for treating the symptoms of erectile dysfunction (ED).
The drugs are phosphodiesterase 5 (PDE5) inhibitors, and their brand and generic names, respectively, are Viagra (sildenafil), Cialis (tadalafil), Levitra (vardenafil), and Stendra (avanafil).
They all have approval from the Food and Drug Administration (FDA), and they have the same function. However, there are some differences between them.
Understanding these differences can help a person choose the most suitable option.
Learn more about ED and premature ejaculation in our dedicated hub.
How do ED medications work?
- The drugs are all PDE5 inhibitors, and they all work in a similar way. They help relax the muscles and increase blood flow to the body.
- This makes it easier for blood to enter the penis, and it allows people with ED to experience a lasting erection during sexual activity.
- The drugs act relatively quickly, but the precise timing depends on the drug.
This table shows when to take the drug, the usual starting dose in milligrams (mg), and how long the effect is likely to last. It is of note that a doctor may adjust the dose for people with certain health conditions and those using other medications. Viagra, Cialis, Levitra, and Stendra are all drugs for treating the symptoms of ED.
A doctor will reach a diagnosis of ED if a person meets one of the following criteriaTrusted Source:
- never being able to get an erection
- often being unable to get an erection
- being able to get an erection but one that does not last long enough for sexual intercourse
- Aspects of physical and mental health can contribute to ED, and a doctor will discuss these and lifestyle habits with the individual before prescribing these drugs.
Doctors may not prescribe the drugs to a person who has a cardiovascular health issue, which makes sexual activity dangerous for them. The drugs are also not suitable for use with certain medications. Below, learn more about medications that can interact with these drugs.
Viagra, Cialis, Levitra, and Stendra have many similar side effects and interactions, but there are also some variations. Anyone considering using these drugs should speak with a doctor first. The drugs may not be suitable for everyone, as they may affect a person’s existing health conditions or interact with other drugs the person is taking.
None of these drugs are suitable for an individual whom a healthcare professional has advised to avoid sexual activity because they have cardiovascular issues or are taking nitrates for a heart condition. Using these drugs with nitrates or alpha-blockers may lead to a sudden fall in blood pressure, resulting in dizziness, faintness, and possibly falls and injuries.
An older study in rodentsTrusted Source suggests that the following medications may increase the concentration of PDE5 inhibitors in the body, and therefore, an individual should consult a doctor before using ED drugs with any of them:
- the antibiotics erythromycin and clarithromycin
- ketoconazole, an antifungal and anti-dandruff agent
- HIV protease inhibitors, such as ritonavir
- Grapefruit juice is a CYP3A4 inhibitor and may increase the impact of these drugs.
Viagra may interact with the following drugs:
- nitrates, such as nitroglycerin
- drugs to decrease blood pressure
- CYP4 inhibitors, such as ritonavir, ketoconazole, and erythromycin
- Cialis interactions and warnings
People should not use Cialis with the following drugs:
- drugs to reduce blood pressure
- CYP3A4 inhibitors, such as ketoconazole and ritonavir, as they can increase the impact
- CYP3A4 inducers, such as rifampin, an antibiotic, as they may prevent Cialis from working
Individuals should not use Levitra if they have an irregular heartbeat or are using the following:
- drugs to lower blood pressure
A doctor may adjust the dose if the person has liver problems or is already using one of the following:
- ritonavir, indinavir, saquinavir, or atazanavir, which are antiretroviral drugs doctors use to treat or prevent HIV
- the antifungal medications ketoconazole or itraconazole
- the antibiotics clarithromycin or erythromycin
- Stendra interactions and warnings
A person should not take Stendra with nitrates or any strong CYP3A4 inhibitors, such as ketoconazole or ritonavir.
A doctor may adjust the dose if an individual is using alpha-blockers or a moderate CYP3A4 inhibitor, such as erythromycin, amprenavir, or diltiazem.
People should take care when using Stendra with the following, as they can lead to a drop in blood pressure:
- drugs to reduce blood pressure
- Other concerns
- Individuals should also take care that their product is an approved version and follow a doctor’s guidance when purchasing any of these drugs.
The choice will depend on a person and various factors, such as whether or not the person has sex regularly, other medications they are taking, and the cost and availability of the ED drugs. Individuals should consult a healthcare professional to help them decide. They do not. They improve blood flow to the penis during an erection, but they do not change the size of the penis. The effects of Cialis (tadalafil) last up to 36 hours, but this only means a person can have an erection or multiple erections within that time. It does not mean they will have an erection lasting 36 hours.