Tadalafil vs Sildenafil: Which is better?

Tadalafil (Cialis) and sildenafil (Viagra) are both popular and effective erectile dysfunction (ED) treatments. They work in a similar way by improving blood flow to the penis and help users to achieve and maintain erections, as they both belong to the same medication group: phosphodiesterase-5 (PDE-5) inhibitors. Their key differences are in how long they last and how they are used.

The duration of each medication is different, and this means they can be taken differently:

• sildenafil (Viagra) usually works for about 4 to 6 hours and should be taken as needed, around an hour before sex
• tadalafil (Cialis) can last up to 36 hours, and it can be taken as needed or daily in a low dose

The right ED treatment for you will depend on how often you need the medication, lifestyle factors, and certain health conditions. For example, sildenafil may be preferred for one-off, occasional use. Tadalafil, on the other hand, is a better option for those looking for flexibility and spontaneity, or for those who have frequent sexual activity, as it can remain effective for up to 36 hours.

How do they work?

Both sildenafil (Viagra) and tadalafil (Cialis) work to treat erectile dysfunction in a very similar way, by increasing blood flow to the penis.

As they are both PDE-5 inhibitors, they work to block an enzyme in blood vessels called PDE-5 that affects blood flow. To treat erectile dysfunction, PDE-5 inhibitors prevent the PDE-5 enzyme from working, which allows the blood vessels in the penis to relax and open up for more blood to flow through. This can make it easier to get and maintain an erection. However, using PDE-5 inhibitors alone will not give you an erection – you must be aroused for them to work.

How long do they last?

One of the main differences between sildenafil and tadalafil is how long they each last. The best option for you may depend on how frequently you need to use it and how spontaneous you like to be.

Sildenafil

Sildenafil lasts around 4 to 6 hours, with peak effectiveness at around 2 to 3 hours after taking it. This shorter duration makes sildenafil ideal for occasional use, to be taken before planned sexual activity.

Tadalafil

Tadalafil which is taken as needed (10mg or 20mg), can last up to 36 hours. Tadalafil in these strengths lasts much longer than sildenafil, making it a better option for spontaneity and more regular sexual activity. It is sometimes referred to as a ‘weekend pill’ for this reason.

If you’re prescribed tadalafil on a daily low-dose, you should always be ready for sex, provided that you are sexually aroused. This option is ideal for those who have sex regularly, 2 or more times per week.

Dosages

Tadalafil and sildenafil prescriptions can differ in dosage because they contain different active ingredients. One of the main differences between the medications is that both can be taken as needed (when you plan to have sex, but only tadalafil can be taken daily at a low dose.

Which dosage you are prescribed will depend on factors like your general health, medical history, age, other medications you currently take, and how well the medication works for you.

Sildenafil doses

Sildenafil is available in strengths of:

• 25mg
• 50mg
• 100mg

Sildenafil is for use as needed, and it should not be used more than once every 24 hours. This medication is most commonly prescribed in the 50mg strength.

Tadalafil doses

Tadalafil is available in various strengths. Tadalafil can be prescribed in the following low doses for daily use in men who have sex frequently:

• 2.5mg
• 5mg

Tadalafil can be prescribed at higher doses for occasional use, as and when it is needed before sex, but these should not be used more than once every 24 hours. These strengths include:

• 10mg
• 20mg

How to take them

Both medications, sildenafil and tadalafil, come as tablets and should be taken orally up to once a day.

How to take sildenafil (25mg, 50mg, and 100mg)

Take 1 tablet when you need it, whatever your dose of sildenafil. You should try to take it around an hour before you plan to have sex, and remember to never take more than one tablet in 24 hours.

Key things to remember about how to take sildenafil include:

• take 1 tablet about 60 minutes before you have sex
• try to avoid eating a heavy meal before taking sildenafil – it works better on an empty stomach
• do not take more than 1 sildenafil tablet a day
• you have to be aroused for sildenafil to help you get an erection – it won't cause one alone
• do not take sildenafil with any other ED medications
• avoid alcohol or limit yourself to no more than 1 or 2 units of alcohol before taking sildenafil – alcohol can impact your ability to get an erection and may increase your risk of side effects like headaches

How to take tadalafil (10mg and 20mg)

These strengths of tadalafil should be taken as needed. The effects of 10mg and 20mg tadalafil tablets can last longer than 24 hours (up to 36 hours), so it’s not recommended to take them every day. You should only take 1 tadalafil tablet within 24 hours (1 day). Try to take one tablet 30 to 60 minutes before you plan to have sex.

Key things to remember about how to take tadalafil as needed include:

• take one tablet 30 to 60 minutes before you have sex
• do not take more than 1 tadalafil tablet per day
• do not take tadalafil with any other ED medications
• avoid or limit alcohol on these doses because it can interfere with the effectiveness of the medication or cause side effects
• you can take tadalafil after eating – most food will not affect it, but try to avoid foods that are high in fat, as these can delay its effect
• you need to be sexually aroused to get an erection on tadalafil – the medication alone will not cause an erection

How to take tadalafil if you are prescribed a daily low-dose (2.5mg and 5mg)

If you are prescribed a daily dose of tadalafil, you should aim to take it at the same time each day. A low dose of 2.5mg or 5mg can be ideal for those who have frequent sexual activity (at least 2 times a week).

Key things to remember about how to take tadalafil daily include:

• take 1 tablet at the same time each day, regardless of when you have sex
• try to avoid fatty food wherever possible, as this may decrease the effectiveness of the medication

Cost differences

Both sildenafil and tadalafil are generic alternatives to the branded versions: Cialis (tadalafil) and Viagra (sildenafil).

Sildenafil starts at a cheaper price compared to tadalafil on Asda Online Doctor. Depending on what your doctor prescribes you in terms of dosage or amount, cost can vary.

Effectiveness

Sildenafil and tadalafil are both effective erectile dysfunction medications. Which medication will be most effective for you often comes down to your personal preference, lifestyle, and specific health needs.

Sildenafil

Sildenafil is an effective treatment providing many people with a strong and reliable erection that is hard enough for sex. Studies show that the standard 50mg sildenafil dose works for 74% of men, and the highest 100mg dose works for 82%.

Tadalafil

Tadalafil is an effective and popular ED treatment because it lasts much longer than sildenafil but works just as well. Tadalafil can last up to 36 hours, so it allows for more spontaneity in sexual activity and means that you can have sex more regularly. In studies, tadalafil was reported to improve erections in: 86% of men with mild ED, 83% in men with moderate ED, and 72% in men with severe ED.

Research into various ED medications suggests that tadalafil is as effective as sildenafil, but may be preferred by patients and their partners because of its longer duration of action.

Tadalafil as a low-dose daily tablet, is also generally safe and well tolerated. This makes it a convenient option for people who prefer not to plan sexual activity around their medication and want to be ready for sex at any time.

Side effects

Here is an overview comparison of the common, uncommon and rare side effects of sildenafil and tadalafil:

Common side effects (affects 1 in 10 people) include:

Uncommon side effects (affects 1 in 100 people) include:

Rare side effects (affects 1 in 1000 people) include:

If you experience any of the following rare side effects when taking sildenafil, dial 111 or 999 in an emergency:

• fainting
• stroke
• heart attack
• irregular heartbeat
• dizziness
• tight throat
• numbness in general or in the mouth
• halos or spots in vision
• eye swelling or discolouration
• bleeding in the back of the eye
• dilation of pupils

If you experience any of the following serious, rare side effects on tadalafil, dial 111 or 999 in an emergency:

• fainting
• seizure
• memory loss
• sudden hearing loss
• hives
• bleeding in semen or penis
• excess sweating

Additional information on the warnings and precautions can be found in the patient information leaflets for sildenafil and tadalafil, which also come with their packaging.

Warnings and contraindications

Tadalafil and sildenafil are both effective medications, however, they may not be right for everyone.

You should tell your doctor before taking tadalafil if you:

• are allergic to tadalafil or ingredients in tadalafil
• are taking organic nitrate or nitric oxide donors (nitrates, ‘poppers’)
• have had serious heart disease
• had a heart attack within the last 90 days
• have low blood pressure or uncontrolled high blood pressure
• have ever had loss of vision
• are taking riociguat for hypertension
• have had sickle cell anemia
• have had cancer of the bone marrow
• have had leukaemia
• have had a serious liver problem
• have had severe kidney problem
• have had pelvic surgery
• have had removal of prostate gland
• have experienced loss sudden decrease or loss of vision
• are under age 18

You should tell your doctor before taking sildenafil if you:

• take nitrates (sildenafil should not be taken together with this type of medication)
• are allergic to sildenafil
• take medications called nitric oxide donors such as amyl nitrite (‘poppers’)
• take riociguat
• have severe heart or liver problems
• have recently had a stroke or heart attack
• have low blood pressure
• have sickle cell anaemia
• have leukaemia
• have certain rare inherited eye diseases, such as retinitis pigmentosa
• have cancer of bone marrow
• have deformity of penis or Peyronie’s disease
• have a stomach ulcer or bleeding problem
• have ever experienced a sudden decrease or loss of vision due to non-arteritic anterior ischaemic optic neuropathy (NAION)

Additional information on the warnings and precautions can be found in the patient information leaflets for sildenafil and tadalafil, which come with their packaging.

Drug interactions

Both sildenafil and tadalafil are effective treatments for erectile dysfunction, however, other medications can affect how they work, and they also may affect how the medication that you are currently taking works.

Speak to your doctor before taking tadalafil if you are currently or thinking of taking:

• medications used to treat high blood pressure (like alpha blockers)
• riociguat
• 5-alpha reductase inhibitor
• ketoconazole or itraconazole (used to treat fungal infections)
• protease inhibitors for HIV or AIDS
• medications used to treat epilepsy
• medications used to treat bacterial infections (like rifampicin, erythromycin and clarithromycin)
• other erectile dysfunction treatments

Speak to your doctor before taking sildenafil if you are currently or thinking of taking:

• medications containing sacubitril or valsarta used to treat heart failure
• medications used to treat chest pain or angina
• nitrates ‘poppers’
• medications for HIV
• medications for high blood pressure
• medications for prostate enlargement

If you have any concerns or questions about your current medication(s) and how they might interact with sildenafil or tadalafil, you should speak to your doctor.

Choosing between tadalafil and sildenafil depends on your personal needs and preferences. Both medications are effective treatments for erectile dysfunction, but which will be the better choice for you depends on how often you need to use them, your personal health, other medications you take, and personal preference.

In summary, you should…

Choose tadalafil if you want:

• a longer-lasting effect (up to 36 hours)
• more spontaneity in your sexual activity
• the option for a daily dose if you are often sexually active

Choose sildenafil if you:

• prefer a shorter-lasting option
• are able to plan sexual activity in advance
• want a medication that may be cheaper
• can avoid eating large meals before taking the medication