Description

Viagra 100mg Tablets (Sildenafil Citrate) – Uses, Dosage, Side Effects & Safety

Viagra 100mg Tablets, containing the active ingredient Sildenafil Citrate, are one of the most widely prescribed treatments for erectile dysfunction (ED) in men. Manufactured and marketed by Pfizer, Viagra helps men achieve and maintain an erection sufficient for satisfactory sexual activity.

⚠️ Safety Alert (Pakistan – DRAP Notice):
The Drug Regulatory Authority of Pakistan (DRAP) has identified falsified and unregistered products labeled as Viagra 100mg Tablets with batch number 19990544AG and manufacturer listed as “Ms. Brooklyn, Ne.” This product is spurious, unregistered, and unsafe. Its quality, safety, and efficacy are not guaranteed. Patients are advised not to use this counterfeit version and to report any adverse reactions to the National Pharmacovigilance Centre.

What is Viagra (Sildenafil)?

• Generic Name: Sildenafil Citrate

• Brand Name: Viagra

• Drug Class: PDE5 inhibitor

• Primary Indications:

  • Erectile Dysfunction (ED) in adult men

  • Pulmonary Arterial Hypertension (PAH)

  • Off-label use: Raynaud’s phenomenon

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Mechanism of Action – How Viagra Works

Viagra enhances the natural erectile response during sexual stimulation:

1. Nitric Oxide Release: Sexual arousal triggers nitric oxide (NO) release in penile tissue.

2. Activation of Guanylate Cyclase: NO increases levels of cyclic guanosine monophosphate (cGMP).

3. Smooth Muscle Relaxation: cGMP relaxes smooth muscles in the corpus cavernosum.

4. Improved Blood Flow: More blood enters the penis, producing an erection.

5. PDE5 Inhibition: Sildenafil blocks PDE5 enzyme, which breaks down cGMP, ensuring stronger and longer-lasting erections.

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Viagra Dosage & Administration

• Standard Starting Dose: 50mg taken 30–60 minutes before sexual activity.

• Adjustments: Based on response, the dose may be reduced to 25mg or increased to a maximum of 100mg once daily.

• Special Populations: Lower doses may be required in elderly patients or those with liver/kidney impairment or those taking CYP3A4 inhibitors.

• Maximum Frequency: One dose per day.

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Inactive Ingredients

• Microcrystalline cellulose

• Anhydrous dibasic calcium phosphate

• Croscarmellose sodium

• Magnesium stearate

• Hypromellose

• Titanium dioxide

• Lactose

• Triacetin

• FD&C Blue #2 aluminum lake

⚠️ Note: Patients with lactose intolerance should avoid Viagra due to lactose content in the coating.

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Drug Interactions & Contraindications

🚫 Do NOT use Viagra with:

• Nitrate drugs (nitroglycerin, isosorbide) → dangerous drop in blood pressure

• Guanylate cyclase stimulators (riociguat) → severe hypotension risk

⚠️ Use caution when combined with:

• Other ED drugs (tadalafil, vardenafil)

• Antifungals, antibiotics, antidepressants (CYP3A4 inhibitors)

• Antihypertensives, anticoagulants, antiseizure drugs

• Herbal supplement St. John’s Wort (reduces effectiveness)

• Alcohol (may increase dizziness, flushing, and reduce ED treatment effectiveness)

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Viagra Side Effects

Common side effects:

• Flushing

• Headache

• Nasal congestion

• Dizziness

• Visual disturbances

Rare but serious risks:

• Sudden vision or hearing loss

• Severe hypotension with nitrates

• Priapism (erection lasting more than 4 hours)

Seek immediate medical help if severe side effects occur.

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Special Warnings

• Bleeding disorders or peptic ulcers: Use with caution.

• Pregnancy & Breastfeeding: Sometimes prescribed for PAH in women; safety not fully established. Small amounts pass into breast milk but are not expected to harm infants.

• Dietary concerns: Contains lactose – avoid if intolerant.

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Storage Guidelines

• Store at 25°C (77°F), with excursions between 15°C – 30°C (59°F – 86°F).

• Keep in original packaging, away from moisture and light.

• Keep out of reach of children.

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Clinical Effectiveness & Reviews

• Clinical trials: Significant improvement in erectile function compared to placebo.

• Average rating: 8.5/10 (Drugs.com, 227+ reviews).

• Positive experience: Reported by 83% of users.

• Common benefits: Restored erectile function, improved sexual performance, overall satisfaction.

• Reported negatives: Headaches, flushing, and mild side effects.