Walk into almost any chemist shop in India, and you can buy a sildenafil tablet without a prescription. No questions asked, Rs 50-100 slid across the counter, maybe wrapped in a newspaper so nobody sees. This is how most Indian men first encounter Viagra — not through a doctor, not through proper medical advice, but through the chemist uncle who doesn’t ask why you need it.

This article is the conversation you should have had before that chemist visit. How these pills actually work, what they can and can’t do, who should never take them, what they cost in India, and most importantly — whether you actually need one.

How Viagra actually works

Viagra’s real name is sildenafil. It belongs to a class of drugs called PDE5 inhibitors. To understand what it does, you need a quick biology lesson.

When you get sexually aroused, your brain sends signals through your nerves to the blood vessels in your penis. These signals trigger the release of a chemical called nitric oxide (NO). Nitric oxide activates an enzyme that produces something called cyclic GMP (cGMP). cGMP is what actually relaxes the smooth muscle in the blood vessels of your penis, allowing them to dilate and fill with blood. That’s your erection.

Now, your body also produces an enzyme called PDE5, whose job is to break down cGMP. It’s the off switch. In normal function, there’s a balance — cGMP builds up (erection happens), PDE5 breaks it down (erection goes away after sex).

In men with ED, the balance is off. Either not enough cGMP is being produced, or PDE5 is breaking it down too fast, or both. The blood doesn’t flow in or stay long enough.

What sildenafil does: it blocks PDE5. That’s it. It inhibits the enzyme that breaks down cGMP, so more cGMP stays active for longer, and blood flow to the penis increases.

Critical point: sildenafil does NOT create arousal. It does NOT make you want sex. It does NOT automatically give you an erection. It only works if you are already sexually stimulated. Without arousal triggering the initial nitric oxide release, the drug has nothing to amplify. You won’t walk around with a random erection for hours — that’s a myth.

Sildenafil vs Tadalafil: what’s the difference?

There are two main PDE5 inhibitors you’ll encounter in India:

Sildenafil (Viagra) — the original. Takes effect in 30-60 minutes. Lasts 4-6 hours. Should be taken on an empty stomach for best results (fatty food delays absorption). Best for planned encounters.

Tadalafil (Cialis) — the newer option. Takes effect in 30-60 minutes but lasts much longer: up to 36 hours. Less affected by food. Can also be taken daily at a low dose (2.5-5 mg) for continuous effect. This is the one nicknamed “the weekend pill.”

Both work by the same mechanism. The main practical difference is duration. Tadalafil is often preferred by men who don’t want to time their dose precisely, or who want spontaneity over a couple of days. Sildenafil is fine if you know when sex is going to happen.

There’s also vardenafil (Levitra) and avanafil (Stendra), but these are less commonly available and used in India.

Indian brands and what they cost

Pfizer’s original Viagra is available in India but expensive — roughly Rs 400-800 per tablet depending on the dose and pharmacy. Most Indian men don’t use it. They use generic versions, which contain the same active ingredient (sildenafil citrate) manufactured by Indian pharmaceutical companies. These generics are legally produced, properly regulated by the DCGI, and bioequivalent to the original.

Common Indian sildenafil brands:

  • Manforce (Mankind Pharma) — probably the most recognized name, Rs 50-100 per tablet
  • Penegra (Zydus Cadila) — Rs 60-120 per tablet
  • Suhagra (Cipla) — Rs 50-100 per tablet
  • Caverta (Sun Pharma) — Rs 80-150 per tablet
  • Vigora (German Remedies) — Rs 40-80 per tablet

Common Indian tadalafil brands:

  • Megalis (Macleods) — Rs 80-150 per tablet
  • Tadacip (Cipla) — Rs 70-130 per tablet
  • Tadalista (Fortune Healthcare) — Rs 50-100 per tablet

Prices vary by dose (25mg, 50mg, 100mg for sildenafil; 5mg, 10mg, 20mg for tadalafil), pharmacy, and city. The numbers above are approximate ranges for standard doses.

A note on the “power” tablets sold in paan shops and roadside stalls: Don’t. These unregulated products may contain unknown doses of sildenafil (sometimes dangerously high), may contain other undisclosed drugs, or may contain nothing at all. If you’re going to take sildenafil, get a proper pharmaceutical brand from a proper chemist.

How to take it properly

Sildenafil:

  • Take 30-60 minutes before anticipated sexual activity
  • Standard starting dose is 50mg. Your doctor may adjust to 25mg or 100mg based on effectiveness and side effects
  • Take on an empty stomach or after a light meal. A heavy or fatty meal significantly delays absorption
  • Do not take more than once in 24 hours
  • You still need sexual stimulation for it to work

Tadalafil:

  • For as-needed use: take 10-20mg about 30 minutes before sex. Works for up to 36 hours
  • For daily use: take 2.5-5mg at the same time every day, regardless of sexual activity. This provides continuous readiness
  • Less affected by food than sildenafil
  • Do not combine as-needed and daily dosing

Side effects

Most side effects are mild and related to the blood-vessel-dilating action of the drug (because PDE5 exists in blood vessels throughout the body, not just the penis):

  • Headache — the most common side effect, reported by 15-25% of users. It’s caused by blood vessel dilation in the brain. Usually mild, resolves in a few hours. Paracetamol helps
  • Facial flushing — redness and warmth in the face. Common, harmless
  • Nasal congestion — blood vessel dilation in the nasal passages. Temporary
  • Indigestion — especially with sildenafil
  • Dizziness — due to mild blood pressure reduction
  • Visual disturbance — sildenafil can cause a temporary blue tinge to vision in some men. This is because PDE6 in the retina is weakly affected. It’s harmless and temporary
  • Muscle aches and back pain — more common with tadalafil
  • Sudden hearing loss — rare but documented cases of sudden sensorineural hearing loss have been reported with PDE5 inhibitors. If you experience sudden hearing changes or ringing in the ears, stop the drug immediately and seek medical attention.

Most side effects decrease with regular use as your body adjusts.

Serious but rare: Priapism — an erection lasting more than 4 hours. This is a medical emergency. If your erection won’t go down after 4 hours, go to a hospital. Untreated priapism can permanently damage the penis. This is very rare, but you should know about it.

Who should NOT take PDE5 inhibitors

This is the section that matters most. Some combinations are genuinely dangerous.

Nitrate medications — ABSOLUTE CONTRAINDICATION. If you take any form of nitrate medication for heart disease — nitroglycerin (sorbitrate, isosorbide mononitrate, isosorbide dinitrate), amyl nitrite (“poppers”) — you must NEVER take sildenafil or tadalafil. Both nitrates and PDE5 inhibitors lower blood pressure through the nitric oxide pathway. Together, they can cause a catastrophic, potentially fatal drop in blood pressure. This is not a theoretical risk. People have died from this combination.

If you have a heart condition and take nitrates, tell your doctor. There may be other options, but PDE5 inhibitors are completely off the table.

Alpha-blockers. If you take alpha-blockers for prostate problems or high blood pressure (prazosin, tamsulosin, doxazosin), the combination with PDE5 inhibitors can cause significant blood pressure drops. It’s not absolutely contraindicated like nitrates, but requires careful medical supervision and dose adjustment.

Grapefruit juice. Grapefruit inhibits CYP3A4, a liver enzyme that metabolizes sildenafil and tadalafil. Drinking grapefruit juice can increase blood levels of the drug, amplifying both effects and side effects. Avoid grapefruit on the day you take it.

Severe heart disease. If you’ve had a recent heart attack, stroke, or have unstable angina, severe heart failure, or uncontrolled blood pressure (very high or very low), PDE5 inhibitors may not be safe. The question isn’t just about the drug — it’s about whether your cardiovascular system can handle the physical exertion of sex.

Severe liver or kidney disease. Dose adjustments are needed.

Retinitis pigmentosa or NAION (a rare eye condition). PDE5 inhibitors may worsen these. If you experience sudden vision loss in one or both eyes, stop the drug immediately and seek emergency medical attention — this could be NAION (non-arteritic anterior ischemic optic neuropathy), and delay in treatment risks permanent vision damage.

The “chemist culture” problem in India

India has a unique relationship with these drugs. Because they’re available over the counter at most chemists despite technically requiring a prescription, millions of men self-prescribe without any medical evaluation.

The problems with this:

Wrong diagnosis. You may not actually have ED. Performance anxiety, premature ejaculation, and low desire are different conditions that require different approaches. A pill that helps blood flow won’t fix anxiety — though it can temporarily mask it. Check out our complete guide to erectile dysfunction to understand the different causes.

Missing underlying conditions. ED is sometimes the first sign of cardiovascular disease, diabetes, or hormonal problems. If you just take a pill without investigating why you have ED, you might miss an early warning sign. ED shares risk factors with heart disease — the arteries in the penis are smaller than coronary arteries, so they clog first. A man with unexplained ED should get his blood sugar, blood pressure, and lipid profile checked.

Wrong dose. Starting at 100mg because “more is better” when 25mg would have worked fine. Or taking multiple tablets at once.

Dangerous combinations. The nitrate interaction described above. A chemist who doesn’t ask about your other medications won’t catch this.

Psychological dependence. Young men who don’t need the drug but take it “just in case” can develop a psychological reliance where they believe they can’t perform without it. This creates the very anxiety the pill was supposed to solve.

Do you actually need it?

Before reaching for a pill, ask yourself these questions:

Do you get morning erections? If yes, your vascular and neurological systems are working. Your ED is likely psychogenic. A PDE5 inhibitor will work, but it’s treating the symptom, not the cause. Read about what morning erections mean.

Did this start suddenly or gradually? Sudden onset ED in a young man is almost always psychological — stress, anxiety, relationship problems, new partner nervousness. Gradual onset over months or years is more suggestive of an organic cause.

Are you under 40 with no major health conditions? Your ED is most likely performance anxiety. Address that first. A PDE5 inhibitor can be useful as a short-term bridge to rebuild confidence, but it shouldn’t be the primary solution.

Is it situational? Works with masturbation but not with a partner? Works with one partner but not another? Works sometimes but not always? All signs of psychogenic ED.

Using PDE5 inhibitors as a bridge (the smart approach)

For young men with performance anxiety, there is a legitimate strategy that many sexual health professionals use: prescribe a PDE5 inhibitor for a limited period — say, 4-6 encounters — to break the failure cycle. When you know the pill is working, anxiety drops. You have successful sex. Your confidence rebuilds. Then you taper off the medication and find you don’t need it anymore.

This works because performance anxiety is a self-reinforcing loop. Success breaks the loop as effectively as failure created it. The pill doesn’t fix the anxiety, but it buys your brain the proof that your body works, which fixes the anxiety.

The key: plan to stop. Don’t use it indefinitely as a crutch.

When to see a doctor

See a doctor before taking PDE5 inhibitors if:

  • You take any heart medications, blood pressure medications, or nitrates
  • You have diabetes, heart disease, or have had a stroke
  • Your ED came on gradually and you’re over 40
  • You have no morning erections and can’t get an erection in any situation
  • You’ve been using PDE5 inhibitors and they don’t work (non-response may indicate a vascular problem that needs investigation)
  • You’ve been using them regularly for more than a few months without addressing the underlying cause

The right order is: understand why you have ED, address the cause, and use medication as a tool within that plan — not as a substitute for the plan. Walk into the doctor’s office, not just the chemist shop.