Cialis vs Levitra: How Similar Are They?


Cialis is a well-known medication intended to treat erectile dysfunction in men. When administered, the drug promotes firm and long-lasting penile erections. Cialis in small dosage (2.5mg daily) is also used to treat some of the symptoms of benign prostatic hyperplasia (BPH), commonly referred to as enlarged prostate. Cialis works by increasing blood flow to the penis, thus causing a full erection for maximum pleasure. After the sexual intercourse, the penis naturally returns to normal size. Since the drug doesn’t act as an aphrodisiac, sexual stimulation is required for it to start working.

Dosage of Cialis

Cialis comes in doses of 2.5mg (mostly used to treat BPH), 5mg, 10mg, and 20mg. Doctors usually advise on the correct dosage depending on the age and severity of erectile dysfunction in every individual case.

Cialis is administered as an oral pill. A man is supposed to take one pill about 30 to 60 minutes before sex. Cialis can be effective for up to 36 hours after taking; that’s the record among all existing ED drugs. So if sexually stimulated, you may have sex more than once within the stipulated time after taking a single pill.


Levitra is a drug used to treat erectile problems. It works by relaxing the smooth muscles found in the walls of blood vessels thus increasing the blood flow to specific areas in the body – in this case, the penis. The mechanism of action is indeed identical to Cialis and other ED drugs that use a PDE5 inhibitor as an active ingredient.

Dosage of Levitra

Levitra comes in three different doses. The initial dose is 10mg, which is taken orally once a day at least 60 minutes before sexual activity. The maximum dose is 20mg within a 24-hour time period. For the older men who are 60 years old and above, the minimal dose of 5mg is recommended, as it reduces the possibility of side effects in older men.

Comparison between Cialis and Levitra


Cialis and Levitra are both oral drugs used to treat erectile dysfunction. They both fall into the class of drugs called PDE5 inhibitors. As such, Cialis and Levitra work in very similar ways. They work by relaxing the certain muscles and increasing blood flow to the penis.

More specifically, Cialis and Levitra function by blocking a particular enzyme referred to as phosphodiesterase type 5 (and that’s why the drugs are called PDE5 inhibitors). They also work by boosting nitric oxide, a chemical in the body known to prompt erections. This helps the muscles in the penis relax thus allowing more blood to flow freely.


Although these drugs are classified under the same group, technically, they have different active ingredients. Cialis is based on tadalafil, while the main active ingredient in Levitra is vardenafil.

Both drugs help to maintain an erection hard enough and long enough to complete intercourse; however, there is a difference in the way how long they stay effective and how quickly they begin to function:

– Cialis lasts for up to 36 hours.

– Levitra works for about 4 to 6 hours after consumption.

– Levitra is recommended to take an hour before sex.

– Cialis starts working 30 minutes after consumption in most cases.

Side Effects of Cialis and Levitra

The possible side effects of Cialis and Levitra are quite similar. The common side effects associated with all PDE5 inhibitors include headaches, nasal congestion, hearing and/or vision impairment, back pain, and stomach upset.


Users should be aware that both drugs interact with nitrates and blood pressure drugs e.g. alpha-blockers. Cialis can also interact with alcohol and cause very low blood pressure resulting in lightheadedness and even fainting.

It is strongly advised not to use these erectile dysfunction medications (in fact, as well as any others) if you fit under the following category:

– If you take nitrates such as nitroglycerin.

– If you take any medication for blood pressure.

– If you take anti-HIV drugs.

– If you have any pathology or injury in the penis.

– If you have heart disease.

– If you have eye disorders.

– If you have an allergic reaction to the components of the drugs.

The above conditions doesn’t always disqualify you from using these drugs, but you must consult with the doctor and get his approval before taking Cialis, Levitra, or other ED drugs.