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ED medicines in the Philippines

Sildenafil: uses, side effects and cost in the Philippines

What sildenafil is used for, how it works, how long it lasts, side effects, who should not take it, and what Viagra and generics cost in the Philippines.

Short answer

Sildenafil is a prescription medicine that treats erectile dysfunction by helping blood flow into the penis when you are sexually aroused. It usually works within 30 to 60 minutes and lasts about 4 hours. Common side effects are headache, flushing and a blocked nose, and it must never be combined with nitrate heart medicines. In the Philippines a generic 50 mg tablet starts at ₱49 (Erecto, TGP), against ₱915 for brand-name Viagra.

Medically reviewed by Pending: licensed PH physicianLast reviewed

What is sildenafil?

Sildenafil is the active ingredient in Viagra, the first pill approved for erectile dysfunction (ED). It belongs to a group of medicines called PDE5 inhibitors and needs a prescription in the Philippines.

Pfizer launched Viagra in 1998. The patent has long expired, so today Philippine pharmacies stock the originator alongside many generics made by local and foreign companies: Spiagra, Zilden, Erecto, RiteMed Sildenafil, Andros, Tigerfil and others. Every one of them contains sildenafil citrate. The tablets come in 25 mg, 50 mg and 100 mg strengths. Which strength suits you, and how often you use it, is decided by your doctor.

Sildenafil sits beside tadalafil (Cialis) as one of the two ED medicines you will realistically be offered here. Our ED medicines overview covers the full list.

What is sildenafil used for?

Sildenafil's main use is treating erectile dysfunction in adult men. A separate product with the same ingredient, Revatio, treats pulmonary arterial hypertension (high blood pressure in the lungs).

Erectile dysfunction

ED means trouble getting or keeping an erection firm enough for sex, often enough that it bothers you. It is common, and it becomes more common with age, diabetes, high blood pressure, smoking and heavy drinking. Sildenafil helps in most of these cases. The European Association of Urology lists PDE5 inhibitors like sildenafil as a first-line treatment for most men with ED.

Sildenafil does not raise desire, does not work without arousal, and does not treat the underlying cause. If your ED comes from poorly controlled blood sugar, blood pressure or a hormone problem, the medicine helps with the symptom while your doctor deals with the cause. That is one reason a proper consultation matters more than the tablet. Read more in what causes erectile dysfunction.

Pulmonary arterial hypertension (Revatio)

Sildenafil also relaxes blood vessels in the lungs. Under the brand Revatio, and as generics, it is prescribed by specialists for pulmonary arterial hypertension (PAH), a serious condition in which the pressure in the lung arteries is too high and the heart strains to pump.

The PAH products are prescribed differently from ED tablets, at different strengths and schedules, under specialist care. If you already take sildenafil for PAH, do not add an ED product on top of it. Tell any doctor who treats you for ED that you are on it.

Uses you may read about online

You will see sildenafil discussed for altitude sickness, for women, and for premature ejaculation. None of these is an approved use in the Philippines. Sildenafil is not a treatment for premature ejaculation; that has its own options, including dapoxetine.

How does sildenafil work?

Sildenafil blocks an enzyme called PDE5, which normally ends an erection. With PDE5 blocked, the chemical signal that keeps blood vessels relaxed lasts longer, so more blood can flow in when you are aroused.

An erection is a blood-flow event. When you are aroused, nerves in the penis release nitric oxide. Nitric oxide raises a messenger molecule called cGMP, which relaxes the smooth muscle in the arteries and spongy tissue. Blood rushes in and the tissue fills. Then PDE5 breaks cGMP down and the erection fades. Sildenafil slows that last step. Step through it below.

How an erection works, step by step
nerve signalartery wall (smooth muscle)spongy tissueNONONOcGMPcGMPcGMPcGMPPDE5sildenafil or tadalafil blocks PDE5

1. Arousal signal

Touch, thoughts or sight send a signal from the brain down the spinal cord to the nerves around the blood vessels of the penis.

Two practical points follow from this. First, sildenafil only works when there is an arousal signal to amplify, so it will not cause an erection by itself. Second, because it acts on the same nitric oxide pathway that nitrate heart medicines use, the two together can drop blood pressure dangerously. That is why the nitrate rule further down is absolute.

How long does sildenafil (Viagra) last?

Sildenafil usually starts working within 30 to 60 minutes and can help for about 4 hours. It reaches its highest level in the blood about an hour after a tablet, and its half-life is about 4 hours.

That 4-hour figure is the window in which an erection is easier to get, not the length of an erection. Once sex is over, the erection should go down normally. An erection that will not go down after 4 hours is a medical emergency called priapism (see the safety box below).

Does food affect sildenafil?

Yes. A high-fat meal slows absorption: in the US FDA label, a high-fat meal delayed the peak level by about an hour and lowered it by about 29%. In practice that means a heavy, oily dinner (crispy pata, lechon kawali, fast-food fried chicken) can make sildenafil feel slower or weaker.

A light meal makes little difference. If sildenafil has seemed not to work for you, the timing of food is one of the first things a doctor will ask about. Tadalafil is not slowed by food in the same way, which is one reason some men prefer it. See sildenafil vs tadalafil.

Why does sildenafil sometimes not work?

The most common reasons are a heavy meal, too little sexual stimulation, high anxiety, alcohol, or trying it only once or twice. The NHS notes that some men need to try it on several occasions before judging it.

If it still does not help, the answer is to go back to your doctor rather than to experiment. They may change the strength, switch you to tadalafil, look again at the cause, or discuss other treatments. Never increase the amount yourself or combine two ED medicines.

Who should not take sildenafil?

Do not take sildenafil if you use any nitrate medicine, use riociguat, or have had a heart attack or stroke recently. Your doctor also has to be careful if you have serious heart disease, very low blood pressure, severe liver disease or certain eye conditions.

The EMA product information and the US FDA label list these situations:

  • Nitrates in any form. Glyceryl trinitrate (nitroglycerin) tablets or spray under the tongue, isosorbide mononitrate or dinitrate, nitrate patches, and recreational "poppers" (amyl nitrite). Combined with sildenafil they can cause a sudden, severe fall in blood pressure.
  • Riociguat, a medicine for some types of pulmonary hypertension.
  • A recent heart attack or stroke, or unstable angina. Your doctor will usually want your heart condition stable before prescribing.
  • Heart disease that makes sex itself unsafe. Sex is physical exertion. If climbing two flights of stairs leaves you with chest pain or breathless, a doctor needs to assess your heart first.
  • Very low blood pressure or uncontrolled high blood pressure.
  • Severe liver disease.
  • Hereditary eye disease such as retinitis pigmentosa, or a previous loss of sight in one eye from NAION (a problem with blood flow to the optic nerve).
  • Allergy to sildenafil or any ingredient in the tablet.

Extra care is needed if you have kidney disease, a bleeding disorder or active stomach ulcer, a penis deformity such as Peyronie's disease, or a condition that raises the risk of priapism (sickle cell disease, multiple myeloma, leukaemia). None of these automatically rules sildenafil out; they are things your doctor needs to know.

What medicines interact with sildenafil?

The dangerous combinations are nitrates and riociguat. Alpha blockers, some antibiotics and antifungals, HIV medicines and grapefruit can also change how sildenafil behaves, so your doctor needs your full medicine list.

  • Nitrates and riociguat: never together (see above). If you have chest pain after taking sildenafil, tell the emergency team which medicine you took and when, so they do not give you a nitrate.
  • Alpha blockers such as tamsulosin, doxazosin and terazosin, common for prostate symptoms and sometimes blood pressure. Together with sildenafil they can cause dizziness on standing. Your doctor may adjust timing or strength.
  • Other blood pressure medicines (amlodipine, losartan and others widely prescribed in the Philippines) add a small extra drop in pressure. For most men on stable treatment this is manageable, but your doctor should know.
  • Strong CYP3A4 inhibitors, which slow the breakdown of sildenafil and raise its level: ritonavir and other HIV protease inhibitors, ketoconazole and itraconazole (antifungals), clarithromycin and erythromycin (antibiotics). Your doctor may choose a lower strength or another medicine.
  • Grapefruit and grapefruit juice can raise sildenafil levels in the same way. Pomelo, a close relative common in the Philippines, may act similarly; ask your doctor or pharmacist.
  • Other ED treatments, including tadalafil, vardenafil, injections, and "herbal" products that often secretly contain a PDE5 inhibitor. Do not combine them.

For the wider picture across all ED medicines, see ED medicine side effects and safety.

What are the side effects of sildenafil?

Most side effects are mild and fade within a few hours: headache, facial flushing, indigestion, a blocked or runny nose, dizziness and changes in colour vision. Serious side effects are rare but need urgent care.

Common side effects

In the clinical trials summarised in the US FDA label, headache affected about 16 in 100 men and flushing about 10 in 100. Indigestion, nasal congestion, back pain, nausea, dizziness, rash and muscle aches were less common. They come from the same blood-vessel widening that helps the erection, so they tend to appear while the medicine is active and settle as it wears off.

  • Headache. The most common. Drinking water helps; in the Philippine heat, dehydration makes it worse.
  • Flushing of the face and neck, and a feeling of warmth.
  • Indigestion or heartburn.
  • Blocked or runny nose.
  • Dizziness, especially when standing up fast.
  • Vision changes: a blue tinge to things, blurring, or extra sensitivity to light. This is because sildenafil also weakly affects a related enzyme (PDE6) in the retina. It is temporary.
  • Back pain and muscle aches, less often than with tadalafil.

If side effects bother you, tell your doctor. A different strength or a switch to tadalafil often helps.

Serious side effects: get urgent care

  • An erection lasting more than 4 hours (priapism). This can permanently damage the tissue. Go to an emergency room.
  • Sudden loss or reduction of vision in one or both eyes. Stop the medicine and seek care at once. This may be NAION, which is rare.
  • Sudden loss or reduction of hearing, sometimes with ringing in the ears or dizziness.
  • Chest pain, fainting or an irregular heartbeat during or after sex. Stop, rest and call for help. Tell responders you took sildenafil.
  • Signs of a serious allergic reaction: swelling of the face, lips or throat, difficulty breathing, or a severe rash.

Can you drink alcohol with sildenafil?

A small amount of alcohol is unlikely to be dangerous for most men taking sildenafil. Heavy drinking is a different matter: alcohol lowers blood pressure, adds to dizziness and itself makes erections harder to get.

The US FDA label reports that sildenafil did not worsen the blood-pressure effect of a moderate amount of alcohol in a study of healthy men. That is not permission for an inuman session. A few rounds of beer or a long night of hard drinks increase dizziness, flushing and headache, and alcohol is one of the most common reasons men report that sildenafil "did not work". If you drink regularly, say so honestly to your doctor; it changes the advice.

Is sildenafil safe?

For most healthy men, sildenafil is a well-studied medicine with a good safety record after more than 25 years of use. It is not safe for everyone, which is exactly why it needs a prescription.

Every medicine has side effects, and sildenafil's serious risks cluster in specific groups: men on nitrates or riociguat, men with unstable heart disease, and men with certain eye conditions. A doctor's job is to find those men before they take it. That check takes a few minutes and usually includes your blood pressure, your medicines, and questions about your heart. It is also a chance to catch the diabetes, hypertension or high cholesterol that often sits behind ED, because ED can be an early sign of heart or blood-sugar problems.

The biggest real-world danger in the Philippines is not genuine sildenafil but fake or unregistered pills. Products sold on marketplaces, through social media, or as "herbal" sex enhancers are a known source of tablets with the wrong dose, a different drug, or contaminants. The US FDA has publicly warned about hundreds of "natural" sexual enhancement products found to contain hidden sildenafil or tadalafil. See how to spot fake ED pills.

Which sildenafil brands are sold in the Philippines?

Philippine pharmacies stock Viagra (the originator) and many generics: Spiagra, Zilden, Erecto, RiteMed Sildenafil, Andros, Tigerfil and others. All contain sildenafil citrate.

A generic registered with the FDA Philippines has to show it is bioequivalent to the originator, meaning it delivers the same amount of sildenafil into the blood at the same rate. You can check any product's registration on the FDA Philippines verification portal. What differs between brands is the maker, the tablet colour and shape, the packaging, and above all the price.

  • Viagra: the Pfizer originator, the most expensive.
  • Spiagra: one of the most searched generics, very low cost at TGP.
  • Zilden: stocked at Watsons and Southstar Drug.
  • Erecto: a TGP staple and the cheapest 50 mg we found.
  • RiteMed Sildenafil: from the RiteMed generics range, at Watsons, Rose Pharmacy and others.

If your doctor writes the generic name, sildenafil, on your prescription, the pharmacist can usually fill it with any registered brand. Ask if you prefer a particular one.

How much does sildenafil cost in the Philippines?

A generic 50 mg tablet starts at ₱49 (Erecto, TGP) and a generic 100 mg tablet at ₱51 (Spiagra, TGP). Brand-name Viagra costs ₱915 for 50 mg and ₱1,168 for 100 mg at Watsons.

At 50 mg, the most expensive verified tablet costs about 19 times the cheapest. The table below shows every verified sildenafil price we hold, with the pharmacy and the date it was checked.

Sildenafil prices in the Philippines
  • sildenafil (Kohagra) 25 mg₱43
    Southstar DrugChecked 2026-10-27 · source
  • sildenafil (Erecto) 50 mg₱49
    TGPChecked 2026-10-27 · source
  • sildenafil (Spiagra) 100 mg₱51
    TGPChecked 2026-10-27 · source
  • sildenafil (Robust Plus) 50 mg₱74.75
    Watsons · ₱299 / 4 packChecked 2026-10-27 · source
  • sildenafil (Tigerfil) 50 mg₱83.50
    WatsonsChecked 2026-10-27 · source
  • sildenafil (Zilden) 50 mg₱94.75
    Southstar DrugChecked 2026-10-27 · source
  • sildenafil (Zilden) 50 mg₱95
    WatsonsChecked 2026-10-27 · source
  • sildenafil (RiteMed Sildenafil) 50 mg₱155
    RiteMed (SRP)Checked 2026-10-27 · source
  • sildenafil (NowExpress generic) 50 mg₱187.50
    NowExpress (online, includes doctor review) · ₱750 / 4 packChecked 2026-10-27 · source
  • sildenafil (Zilden) 100 mg₱187.75
    WatsonsChecked 2026-10-27 · source
  • sildenafil (NowExpress generic) 100 mg₱212.50
    NowExpress (online, includes doctor review) · ₱850 / 4 packChecked 2026-10-27 · source
  • sildenafil (RiteMed Sildenafil) 100 mg₱250.25
    Rose PharmacyChecked 2026-10-27 · source
  • sildenafil (RiteMed Sildenafil) 100 mg₱250.75
    WatsonsChecked 2026-10-27 · source
  • sildenafil (Andros) 50 mg₱574
    WatsonsChecked 2026-10-27 · source
  • sildenafil (Viagra) 25 mg₱683
    WatsonsChecked 2026-10-27 · source
  • sildenafil (Andros) 100 mg₱736.75
    WatsonsChecked 2026-10-27 · source
  • sildenafil (Viagra) 50 mg₱915
    WatsonsChecked 2026-10-27 · source
  • sildenafil (Viagra) 100 mg₱1,168
    WatsonsChecked 2026-10-27 · source
Prescription required for every medicine listed. Last checked October 27, 2026

Some points to read the table correctly:

  • Prices are per tablet unless the row says pack. Robust Plus and the NowExpress generics are sold in packs of 4.
  • Pharmacy prices move. TGP and Southstar Drug often undercut Watsons and Mercury Drug on generics; RiteMed publishes a suggested retail price.
  • A higher strength is not automatically "better value". The strength is a medical decision for your doctor, not a cost choice.

For a deeper breakdown by strength and pharmacy see sildenafil prices in the Philippines, and for the originator against every generic see Viagra price in the Philippines. To work out a monthly cost, try the cost per dose calculator.

Do you need a prescription for sildenafil in the Philippines?

Yes. Sildenafil is a prescription medicine in the Philippines, and licensed pharmacies such as Watsons, Mercury Drug, Southstar Drug, Rose Pharmacy and TGP will ask for one.

You can get a prescription from any licensed doctor: a general practitioner, an internist, or a urologist. Many men in Metro Manila, Cebu and Davao now do this through an online consultation, which avoids sitting in a clinic waiting room and suits night-shift and BPO schedules. The doctor asks about your health, your medicines and your heart, and if sildenafil suits you, sends an e-prescription. Expats can use the same route; see prescription rules for foreigners.

Read is Viagra over the counter in the Philippines? for the rules, and online ED consultation for how online care works and what it costs.

What should you tell your doctor before taking sildenafil?

Tell your doctor every medicine you take, including anything for the heart, blood pressure, prostate, HIV or infections, plus supplements and "herbal" products. Also mention any heart, liver, kidney or eye problem and how much you drink.

A short checklist to bring:

  1. Do I take any nitrate, even occasionally (a spray or tablet under the tongue for chest pain)?
  2. Have I had a heart attack, stroke or chest pain in the past six months?
  3. Can I climb two flights of stairs without chest pain or getting very breathless?
  4. Do I take medicine for blood pressure or for prostate symptoms?
  5. Have I ever had sudden vision loss in one eye?
  6. Do I drink alcohol most days, or heavily on weekends?
  7. Have I already tried sildenafil, tadalafil or a "herbal" product, and what happened?

Honest answers keep you safe and help the doctor choose between sildenafil, tadalafil and other options.

Frequently asked questions

What is sildenafil used for?

Sildenafil is used to treat erectile dysfunction in adult men. A different product made with the same ingredient (Revatio) treats pulmonary arterial hypertension, a lung blood vessel condition.

How long does Viagra last?

Sildenafil usually starts working in 30 to 60 minutes and can help for about 4 hours. It does not cause a 4-hour erection: it makes an erection possible when you are aroused during that window.

Can I drink alcohol with sildenafil?

A small amount is unlikely to be dangerous for most men, but alcohol lowers blood pressure, adds to dizziness and makes erections harder to get. Heavy drinking works against the medicine. Ask your doctor what is sensible for you.

Is sildenafil safe?

For most healthy men, yes, when a doctor has checked that it suits them. It is not safe with nitrate medicines or riociguat, after a recent heart attack or stroke, or with some serious heart, eye and blood pressure conditions.

Do you need a prescription for sildenafil in the Philippines?

Yes. Sildenafil is a prescription medicine in the Philippines. A licensed doctor can prescribe it after an in-person or online consultation, and any licensed pharmacy can fill it.

Is generic sildenafil the same as Viagra?

It contains the same active ingredient. A generic registered with the FDA Philippines has to show it behaves the same way in the body as Viagra. Price, maker and tablet appearance differ.

Sources

  1. 1.Viagra (sildenafil citrate) prescribing information. US Food and Drug Administration.
  2. 2.Sildenafil (Viagra). NHS.
  3. 3.Side effects of sildenafil. NHS.
  4. 4.Common questions about sildenafil. NHS.
  5. 5.Sildenafil. MedlinePlus, US National Library of Medicine.
  6. 6.Viagra: EPAR (product information). European Medicines Agency.
  7. 7.Revatio: EPAR. European Medicines Agency.
  8. 8.EAU Guidelines on Sexual and Reproductive Health. European Association of Urology.
  9. 9.Tainted sexual enhancement products. US Food and Drug Administration.

This site is for education only and is not medical advice: diagnosis and treatment, including whether a medicine is right for you and how much to take, are decided by a licensed doctor.

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