What Is Sildenafil?
Sildenafil is a PDE5 inhibitor. It works by relaxing the blood vessels in the penis, allowing increased blood flow during sexual stimulation. It does not cause spontaneous erections. You still need to be aroused for it to work.
Sildenafil was the first oral ED medication approved by the US FDA in 1998. Since then, it has been prescribed to hundreds of millions of men globally. The generic versions contain the same active ingredient at the same dosage and undergo the same regulatory review for safety and efficacy.
How Sildenafil Works
Take it 30 to 60 minutes before sexual activity. The medication is most effective on an empty stomach or after a light meal. High-fat meals can delay absorption and reduce effectiveness.
The effects last for up to 4 hours. This means you have a window of up to 4 hours during which achieving and maintaining an erection is easier. It does not mean you will have an erection for 4 hours.
Sexual stimulation is required. Sildenafil helps your body respond to arousal. It does not create arousal on its own.
Most men notice the effects within 30 minutes of taking the tablet.
Dosages Available
50mg is the standard starting dose for most men. Your doctor may recommend starting here and adjusting based on your response.
100mg is the maximum recommended dose. It may be appropriate if 50mg is not sufficiently effective. Your doctor will advise.
The right dose depends on your health profile, other medications, and how you respond. Starting at 50mg and adjusting is the standard medical approach. Do not increase your dose without consulting a doctor.
Pricing on NowExpress
Generic Sildenafil:
- 50mg x 4 tablets: ₱839 (approximately ₱210 per tablet)
- 100mg x 4 tablets: ₱889 (approximately ₱222 per tablet)
Pfizer Viagra:
- 50mg x 4 tablets: ₱6,139
- 100mg x 4 tablets: ₱7,889
All prices include a free doctor consultation and free discreet delivery. No hidden fees.
Generic vs Branded: Both contain the same active ingredient (sildenafil citrate) at the same dosage. The difference is price and manufacturer. Generic sildenafil is a legitimate, regulated product. Many doctors prescribe generics as first-line treatment because the clinical outcome is the same.
How to Buy Sildenafil Through NowExpress
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Complete the health assessment on NowExpress. This takes about 5 minutes and covers your medical history, current medications, and symptoms.
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Free doctor review. A licensed Philippine doctor evaluates your health profile. If sildenafil is safe and appropriate, they will issue a prescription. If not, they will explain why. You are not charged unless you are approved.
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Choose your product. Select generic sildenafil or Pfizer Viagra in your preferred dosage.
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Discreet delivery. Your order ships in plain, unmarked packaging. Free delivery.
NowExpress is an FDA-licensed facility. Medications are sourced from verified pharmaceutical partners, including Pfizer. This is not an unregulated marketplace. Every order goes through a proper medical and pharmaceutical process.
Who Should (and Should Not) Take Sildenafil
Sildenafil is suitable for most adult men with erectile dysfunction. However, there are important contraindications.
Do not take sildenafil if you:
- Use nitrate medications (nitroglycerin, isosorbide mononitrate, isosorbide dinitrate, or recreational nitrites/"poppers"). The combination can cause a severe, dangerous drop in blood pressure.
- Have been told by a doctor to avoid sexual activity due to a cardiovascular condition.
- Are allergic to sildenafil or any inactive ingredients in the tablet.
Tell your doctor if you have:
- Heart disease, angina, or a history of heart attack or stroke
- Very low blood pressure (below 90/50 mmHg) or uncontrolled high blood pressure
- Liver or kidney problems
- A bleeding disorder or active stomach ulcer
- Peyronie's disease
- Conditions that predispose to priapism (sickle cell disease, multiple myeloma, leukemia)
Medication interactions to be aware of: Alpha-blockers (for blood pressure or prostate), certain antifungals, HIV protease inhibitors, and some antibiotics can interact with sildenafil. The health assessment and doctor review are specifically designed to catch these.
Side Effects
Most men tolerate sildenafil well. The most common side effects are mild and temporary:
- Headache
- Facial flushing (redness or warmth in the face)
- Nasal congestion
- Upset stomach
- Dizziness
- Visual changes (slight blue tint to vision, increased light sensitivity)
These typically subside within a few hours. If side effects are persistent or bothersome, your doctor can adjust your dosage or recommend switching to tadalafil, which some men tolerate differently.
Seek medical attention immediately if you experience: an erection lasting more than 4 hours (priapism), sudden vision loss, sudden hearing loss, or chest pain.
Sildenafil vs Tadalafil: Quick Comparison
Not sure which one is right for you? Here is the key difference.
| Feature |
Sildenafil |
Tadalafil |
| Duration of effectiveness |
Up to 4 hours |
Up to 36 hours |
| Onset |
30-60 minutes |
30 min to 2 hours |
| Food sensitivity |
Works best on empty stomach |
Minimal food interaction |
| Daily use option |
No |
Yes (5mg) |
| Starting price (NowExpress) |
₱839 for 4 tablets |
₱4,639 for 2 tablets (Cialis) |
Sildenafil is more affordable per dose and works well if you can plan ahead. Tadalafil offers a longer window and more flexibility. Many men try both and settle on the one that fits their lifestyle better. Learn more about tadalafil options here.
For a full guide on all ED treatment options, see our comprehensive ED treatment page.
Frequently Asked Questions
Is generic sildenafil as effective as Viagra?
Yes. Generic sildenafil contains the same active ingredient (sildenafil citrate) at the same dose. It undergoes the same regulatory standards for safety and efficacy. The clinical effect is identical.
Can I take sildenafil with alcohol?
Moderate alcohol (one to two drinks) is generally acceptable. However, excessive alcohol impairs erections on its own and reduces the medication's effectiveness. It can also increase the risk of side effects like dizziness and low blood pressure.
How often can I take sildenafil?
No more than once per day. The standard recommendation is to take it only when needed, 30 to 60 minutes before sexual activity.
What happens if sildenafil does not work?
Try it at least 4 to 6 times before concluding it is not effective. The first time is not always representative. Make sure you are taking it on a relatively empty stomach and allowing enough time for it to take effect. If it still does not work, your doctor may adjust the dose or recommend switching to tadalafil.
Do I need to take sildenafil every day?
No. Sildenafil is an as-needed medication. Take it when you plan to be sexually active. If you prefer a daily medication that keeps you ready at all times, daily tadalafil (5mg) is the better option.
Is it safe to buy sildenafil online?
It depends entirely on the source. NowExpress is FDA-licensed, sources from verified pharmaceutical partners, and requires a doctor review before dispensing. Look for these credentials with any online provider. Avoid sites that sell without a medical consultation or that disclaim being licensed facilities.
Will the packaging reveal what is inside?
No. All NowExpress deliveries use plain, unmarked packaging. There is no visible branding, product name, or indication of the contents.
Ready to get started? Start your free consultation and a licensed doctor will review your case privately. If approved, medication ships to your door in discreet packaging.
