Sildenafil vs tadalafil: which suits you, and what each costs in pesos

What is the difference between sildenafil and tadalafil?

The key difference is duration: sildenafil helps for about 4 hours, tadalafil for up to 36 hours. Everything else, from food effects to side effects to daily use, follows from how long each stays in the body.

Both are PDE5 inhibitors. They block the enzyme that ends an erection, so the body's normal response to arousal works more fully. Neither causes an erection by itself, raises desire, or treats the cause of ED. Sildenafil's half-life is about 4 hours; tadalafil's is about 17.5 hours. That is why one is a "tonight" medicine and the other is often called a "weekend" medicine. The full background is on our sildenafil and tadalafil pages.

How do sildenafil and tadalafil compare side by side?

The table below compares the two on the points that matter in daily life, using the US FDA labels and NHS guidance. Prices are the cheapest and highest verified per-tablet prices in the Philippines.

	Sildenafil (Viagra)	Tadalafil (Cialis)
Starts working	30 to 60 minutes	from about 30 minutes; often 1 to 2 hours
How long it can help	about 4 hours	up to 36 hours
Half-life	about 4 hours	about 17.5 hours
Effect of a heavy, high-fat meal	slower, weaker start	no meaningful effect
Daily low-strength option	no	yes (2.5 mg and 5 mg)
Also approved for BPH symptoms	no	yes
Most common side effects	headache, flushing, indigestion, blocked nose, blue-tinged vision	headache, indigestion, back pain, muscle aches, blocked nose
Strengths that exist	25, 50, 100 mg	2.5, 5, 10, 20 mg
Generic in the Philippines	many (Spiagra, Zilden, Erecto, RiteMed)	fewer (Torfil, Tadah Forte, Thafil)
Cheapest verified tablet (50 mg / 20 mg)	₱49	₱395
Highest verified tablet (50 mg / 20 mg)	₱915	₱1,053.75
Cheapest verified tablet (100 mg / 10 mg)	₱51	₱220

The strengths in each price row are paired only so you can compare commonly prescribed tablets. They are not equivalent doses, and the strength you need is a medical decision.

Which works faster?

Both can start working in about 30 minutes, and both commonly take closer to an hour. Sildenafil tends to reach its peak a little sooner on an empty stomach; tadalafil's peak is around 2 hours.

In everyday terms the difference in speed is small. What changes things is food. A high-fat meal delays sildenafil by about an hour and blunts its peak, while tadalafil is not meaningfully affected. If your evenings revolve around a big dinner, that may matter more than minutes on a label.

Which lasts longer?

Tadalafil, by a wide margin: up to 36 hours against about 4 hours for sildenafil. Neither causes an erection that lasts that long; the window is when an erection comes more easily with arousal.

The long window means less planning and less pressure to time things. Some men and their partners find that takes away anxiety, which itself helps. Others prefer sildenafil precisely because it is out of the system by the next morning, which can matter if you work early shifts, drive long distances, or want side effects to pass quickly.

Which has fewer side effects?

Both are well tolerated, and their common side effects overlap: headache, flushing, indigestion and a blocked nose. The differences are in the details: sildenafil more often causes flushing and blue-tinged vision, tadalafil more often back pain and muscle aches.

Because tadalafil lasts longer, its side effects can also last longer. Back pain from tadalafil typically starts 12 to 24 hours after a tablet. Sildenafil's side effects usually pass within a few hours. If one medicine gives you side effects you dislike, the other may suit you better; that is one of the most common reasons doctors switch patients. The full list, including the rare serious effects, is in ED medicine side effects and safety.

Do they interact with the same medicines?

Yes. Both must never be combined with nitrates or riociguat, both need care with alpha blockers and blood pressure medicines, and both are affected by strong CYP3A4 inhibitors and grapefruit.

The practical difference is time. Because tadalafil stays in the body much longer, the gap before a nitrate could safely be given in an emergency is longer: the US label for tadalafil says at least 48 hours. If you have a heart condition, or you might ever need a nitrate for chest pain, this is a point to discuss with your doctor before choosing.

What does each cost in the Philippines?

Sildenafil is clearly cheaper. A generic 50 mg sildenafil tablet starts at ₱49 (Erecto, TGP), while the cheapest verified 20 mg tadalafil is ₱395 (Torfil, Watsons).

Brand names close the gap a little at the top. Viagra 50 mg is listed at ₱915 a tablet at Watsons; Cialis 20 mg at ₱985.25. The spread between brand and generic is also bigger for sildenafil: at 50 mg the priciest tablet costs about 19 times the cheapest, against about 3 times for tadalafil at 20 mg.

Cost per tablet is not the whole story. Because one tadalafil tablet covers up to 36 hours, some men who are sexually active on consecutive days use fewer tablets than they would with sildenafil. Daily tadalafil is a different calculation again: about 30 tablets a month, priced on our daily tadalafil page. For full lists by pharmacy see sildenafil prices and tadalafil prices, or compare brands such as Spiagra and Torfil.

Who might suit sildenafil, and who might suit tadalafil?

Sildenafil often suits men who have sex occasionally, can plan a little, want the lowest cost and prefer the medicine gone by morning. Tadalafil often suits men who want a longer window, eat a big meal in the evening, have sex several times a week, or also have prostate symptoms.

These are tendencies, not rules. Studies comparing the two find that both work for most men, and when men try both, preferences split. Many Filipino doctors start with a generic sildenafil because it is inexpensive and well understood, then switch if side effects, timing or response are not right. Some men with BPH start directly on daily tadalafil because it treats both conditions.

Things that may push the decision one way:

• Budget is tight: generic sildenafil is the cheaper starting point.
• Heavy dinners, unpredictable schedules, night shifts: tadalafil's food independence and long window help.
• Prostate symptoms (BPH): daily tadalafil may treat both.
• Back pain or muscle aches on tadalafil: sildenafil may be better tolerated.
• Flushing or vision changes on sildenafil: tadalafil may be better tolerated.
• Heart disease, or a chance you might need a nitrate: discuss with your doctor; the shorter action of sildenafil is one factor they weigh.

What questions should you ask your doctor?

Go in with your routine, your medicine list and these questions. The answers will decide the choice far better than any comparison table.

1. Given my health and medicines, is either one unsafe for me?
2. How often do I expect to need it, and does that point to sildenafil, on-demand tadalafil or daily tadalafil?
3. I eat my main meal late at night. Does that change your advice?
4. I take medicine for blood pressure or my prostate. How do we plan around it?
5. If I get side effects, should I switch or change strength?
6. How many tries should I give it before we decide it is not working?
7. Is a generic brand fine for me, and which pharmacy near me stocks it?
8. Should we test my blood sugar, cholesterol or testosterone as well?

Never combine sildenafil and tadalafil, and never switch on your own. If you have already tried either medicine, or a "herbal" product, tell your doctor what you used and what happened; it helps them advise you.

Can you try one and then the other?

Yes, and many men do. Trying one, then the other under your doctor's guidance, is a normal way to find the better fit, and studies of men who tried both show preferences split between them.

A fair trial usually means several attempts, not one. The NHS notes that some men need a few tries before a PDE5 inhibitor works well, because anxiety, a heavy meal or alcohol can blunt the first experience. Keep a simple note of what happened each time: how soon it helped, how long the effect lasted, and any side effects. Bring it to your follow-up. That record tells your doctor far more than "it did not work".

If neither medicine helps after a proper trial, it is not the end of the road. A doctor can look again at the cause, check testosterone and blood sugar, and discuss other treatments with a urologist. For the rest of the options, see the ED medicines overview.

How do you get a prescription for either?

See a licensed doctor in person or online. Both medicines need a prescription in the Philippines, and the same consultation can choose between them.

An online consultation is private, fits around work, and ends with an e-prescription that pharmacies such as Watsons, Mercury Drug and Southstar Drug can fill. Read online ED consultation for how it works, or return to the ED medicines overview.

Frequently asked questions

Which is better, Viagra or Cialis?+

Neither is better for everyone. Studies show both work for most men with ED. Sildenafil (Viagra) is shorter-acting and cheaper; tadalafil (Cialis) lasts up to 36 hours, is not slowed by food and has a daily option. Your doctor helps you choose.

Is tadalafil stronger than sildenafil?+

Not in the sense of a firmer erection. The difference is mainly how long each lasts. Comparing milligrams between the two is meaningless, because they are different molecules used at different strengths.

Can I switch from sildenafil to tadalafil?+

Yes, with your doctor's guidance. Switching is common when one medicine gives side effects or does not suit your routine. Never take both together.

Which is cheaper in the Philippines, sildenafil or tadalafil?+

Sildenafil. Generic sildenafil tablets are among the cheapest ED medicines in the country, while the cheapest verified generic tadalafil 20 mg costs several times more per tablet.

Can I take sildenafil and tadalafil together?+

No. Combining two PDE5 inhibitors raises the risk of low blood pressure and other side effects without a proven benefit.