Sildenafil Vs Tadalafil: Everything You Need To Know

sildenafil vs tadalafil

Sildenafil vs Tadalafil – in this article, we make a comparison between both the medicines on multiple factors, like dosage, side effects, etc.


Sildenafil and tadalafil are both medications generally used for treating erectile dysfunction or ED. Although tadalafil is also used to treat Benign Prostatic Hyperplasia or BHP. Sildenafil is sold popularly under the brand name Viagra by Pfizer.

Tadalafil, on the other hand, is sold by Eli Lilly & Co. under the brand name Cialis. While both the drugs are used for treating the same medical condition, their suitability towards patients is very subjective, as it varies from patient to patient. Although, it is observed that people who use Sildenafil or Tadalafil, generally alternate between the two drugs, instead of sticking to one.

Sildenafil Vs Tadalafil

Both Sildenafil and tadalafil come under the category of PDE5 inhibitor drugs, which means that these drugs inhibit the growth of PDE5 enzymes in the body and result in an increased concentration of cGMP levels, which leads to better erections among men taking the medications. Since both these drugs rely on the natural release of nitric oxide in the body, the person must be in a state of sexual arousal when taking either Sildenafil or Tadalafil.

1. Dosage

Sildenafil and Tadalafil both are used to treat the same medical condition, but both of them vary greatly when it comes to dosage. Sildenafil is available in the market in doses of 25 mg, 50 mg, and 100 mg, depending upon the need of the patient. On the contrary, the largest dose of tadalafil is just 20 mg, much lesser than the smallest dose of Sildenafil.

The standard dose of Sildenafil that is generally administered is 50 mg. This can be peaked to 100 mg if a dose of 50 mg is not sufficient, or, dropped to 25 mg, if a dose of 50 mg causes strong side effects. Tadalafil meanwhile has a standard dose of 10 mg when taken on a need only basis, which can be increased or decreased by 5 mg as per the need of the person.

When taken regularly, tadalafil is administered in doses of 2.5 mg. This maintains a steady supply of the drug in the body. The onset time for Sildenafil is at about 11 minutes, although one must wait for around 1-2 hours to experience the best effects.

Tadalafil, on the other hand, has an onset time of around 15-30 minutes, and to experience the best effects, the person must wait for around an hour or so. The half-life of Tadalafil is around 24 hours and that of Sildenafil is noted to be approximately 4-6 hours. As a result, tadalafil lasts for a very long time as compared to Sildenafil, which is why it is known as the “weekend drug”.

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2. Side Effects

Both Sildenafil and tadalafil belong to the class of PDE5 inhibitor drugs and hence have similar side effects. These include flushing (reddening) of the neck and cheeks, muscle pain, temporary loss or disturbance of vision, dizziness, nausea, indigestion, or a stuffy nose.  

Most of these side effects like muscle ache and blurred vision are a direct cause of lack of blood flow to the upper body, as most of it flows towards the penis. Altered color vision is sometimes also experienced by some men who take Sildenafil or Tadalafil. This occurs considering the lack of blood flow to the brain impacts the human ability to comprehend their surroundings and differentiate between colors like green and blue.

A major side effect of both drugs is a drop in blood pressure. This is a major point of concern for anyone who is on a blood pressure medication, or any drug for the treatment of angina, and is taking Sildenafil or tadalafil.

This point must always be considered when taking any ED medication because a sudden drop in blood pressure may lead to nausea, blurred vision, fainting, and even heart attack. Remember, only if you are consuming other blood pressure pills with these ED pills can a serious drug interaction occur.

A major side effect of Tadalafil (Cialis) is priapism. Priapism, in simple terms, implies irregular and prolonged erections. This is normally seen when people consume a high dose of Cialis or even Viagra. Meanwhile, indigestion and pain in the limbs are common side effects, particularly linked to tadalafil or Cialis.

3. Price

Price plays the role of a major deciding factor when it comes to the choice of buying any one of the two between Sildenafil and tadalafil. Sildenafil is the cheapest ED treatment available in the market for $24 to $35 for a 30 pill bottle of standard 50 mg doses.


Tadalafil on the other end is a quite expensive medication that easily costs more than Viagra.

4. Mode Of Administration

Sildenafil is used in the treatment of ED as well as PAH or Pulmonary Arterial Hypertension. When used for ED, Sildenafil is administered orally in the form of pills of 25 mg, 50 mg, and 100 mg. When used for PAH, Sildenafil may be administered orally (10 mg or 20 mg pills) or via an intravenous syringe (12.5 ml doses).

Tadalafil is administered orally for the treatment of ED or Benign Prostatic Hyperplasia or BPH, the form of pills with doses of 2.5 mg, 10 mg, and 20 mg as per the need of the patients. 

Sildenafil Vs Tadalafil: Extra Information

Since both of the medicines belong to the class of PDE5 inhibitors, certain points must always be considered when taking either Sildenafil or Tadalafil. 

Sildenafil must be consumed on an empty stomach as food hampers the absorption of Sildenafil into the bloodstream, especially high-fat foods. If consuming the medicine on an empty stomach is not possible. Then the patient must consume foods that are light and low in fat.

Any such fruit or juice must also be avoided that interferes with the absorption of Sildenafil, such as grapefruit juice. However, Tadalafil can be consumed regardless of this fact as the digestion of food does not hamper or interfere with its absorption in any way. 

Sildenafil or Viagra must not be taken by anyone who is being treated for PAH as PAH medication (Revatio) also contains Sildenafil and taking more Sildenafil for ED can cause adverse side effects and may even damage the blood vessels.

Patients who take blood pressure medicines must also be very careful when taking Sildenafil or tadalafil as both of these medicines usually cause a drop in the blood pressure and mixing them with other BP medicines could lead to a sharp decline in blood pressure, which could result in complications ranging from fainting to long term coma or even death.

Be sure never to mix Sildenafil or tadalafil with any form of nitrates or alpha-blockers as this would interfere with the normal nitric oxide release mechanism of the body.

Sildenafil Vs Tadalafil: Conclusion

Even though both Sildenafil and tadalafil are used for the same purpose, they vary greatly in their lasting effects. These medicines also have a vast list of contraindications and hence, self-medication and dosage advice mentioned on the packaging or internet must be avoided.

Instead, one must approach their doctor and get a proper prescription after a thorough analysis of their medical history and allergic reactions to medicines, if any, and other factors like contraindicated medicines, existing health conditions, and side effects of the drugs.