Tadalafil is known under the brand name Cialis or Adcirca. As Cialis, it is used to treat erectile dysfunction. Under the trade name of Adcirca, it is used for pulmonary arterial hypertension.
Similar drugs to Cialis include Viagra and Levitra.
What is Cialis?
Erectile dysfunction can affect men of any age.
Cialis is a phosphodiesterase type 5 (PDE5) inhibitor. A PDE5 inhibitor is a medication that blocks the action of a substance known as cyclic guanosine monophosphate (cGMP), in the cells that form part of the blood supply to the penis.
The muscles of the arteries in the walls of the lungs also contain PDE5, which is why tadalafil can also help with pulmonary hypertension treatment.
Cialis comes in yellow, film-coated and almond shaped tablets in 5, 10 and 20 milligram (mg) doses.
Cialis was approved by the United States Food and Drug Administration (FDA) in 2003 for the treatment of erectile dysfunction. In May 2009 tadalafil received approval for the treatment of pulmonary arterial hypertension.
In 2011, it was approved for benign prostatic hyperplasia, a condition in which the prostate gland becomes enlarged, causing problems with urination.
Patients with erectile dysfunction can take Cialis as needed, but it should not be taken more frequently than once every 24 hours.
For the medication to work, the man needs to be sexually aroused. The drug does not provide an erection without sexual stimulation.
What does Cialis do?
Penile erection occurs when the penis fills with blood. This happens because the blood vessels that bring blood flow to the penis dilate, thus increasing the blood supply. At the same time, the blood vessels that remove blood from the penis contract. As a result, blood accumulates, causing an erection.
When a man is sexually stimulated, nitric oxide is released into the penis. Nitric oxide enables the production of cGMP, which controls the dilation and contraction of the blood vessels that carry blood to and from the penis.
Another substance, PDE5, destroys cGMP. When this occurs the blood vessels return to their normal size and the erection ends. Tadalafil stops PDE5 from destroying cGMP. This causes the erection to last for longer.
Cautions and adverse effects
A man who is taking a nitrate drug prescription for heart problems or chest pain should not use tadalafil.
The producers of the drug, Eli Lilly, warn that if the following symptoms occur during sexual activity, they could be a sign of a serious complication, and immediate medical assistance should be sought:
- Numbness, tingling or pain the jaw, arms, chest, or neck
If an erection lasts for more than 4 hours, this is known as priapism. It can damage the penis, so medical assistance is necessary.
In rare cases, Cialis can undermine the blood flow to the optic nerve of the eye, causing sudden loss of vision. This is more likely in patients with hypertension, diabetes, high cholesterol, pre-existing eye problems, or heart disease.
A man with high or low blood pressure should not use Cialis unless their physician agrees.
People with the following conditions should not take Cialis unless a physician agrees:
- People with heart rhythm problems
- Patients who have experienced congestive heart failure or stroke within the last 6 months, or myocardial infarction within the last 3 months
- Those with sickle cell anemia, multiple myeloma, leukemia or another blood cell disorder
- Patients with hemophilia
- People with liver or kidney disease
- Individuals with a stomach ulcer
- Patients with retinitis pigmentosa
- People with Peyronie's disease, or some other structural deformity of the penis
- Those with heart disease
- People who have been advised not to have sexual intercourse for health reasons
- Individuals with Angina
- High or low blood pressure
How should it be used?
Tadalafil for erectile dysfunction is only for use by adults aged 18 years and above.
Tadalafil is also prescribed for pulmonary arterial hypertension and benign prostatic hyperplasia.
A first dose is 10 mg at least 30 minutes before sexual activity. Dosage can then be adjusted depending on how the individual responds. The maximum is 20 mg as a single dose.
The patient should take no more than one dose in 24 hours, but a daily dose of 10 mg to 20 mg is not recommended. This is because a portion of the drug remains in the system for at least 24 hours.
Patients who expect to be sexually active at least twice a week can take a daily dose of 5 mg, and this may be reduced to 2.5 mg once daily, depending on the individual reaction.
Cialis is available on prescription and should be used under the supervision of a medical professional.
It can be purchased online, but this is not advisable.
The FDA issued a warning in 2015 about counterfeit tadalafil tablets that had become available in the U.S. It is important always to obtain medications from a reputable source, because using fake drugs can be dangerous.