Viagra (sildenafil) Tablets

Viagra is a prescription medicine used to treat erectile dysfunction (ED) by improving penile blood flow during sexual stimulation. This page summarizes dosing basics, expected effects, key safety warnings, interaction risks, and storage so site visitors can compare label information before submitting a prescription request. Ships from Canada to US is available through partner dispensing pharmacies, with cash-pay access that may help people without insurance when coverage is not an option and a valid prescription is provided.

What Viagra Is and How It Works

Sildenafil is a phosphodiesterase type 5 (PDE5) inhibitor, a class that supports erections by helping blood vessels relax in the penis. It works by enhancing nitric oxide–mediated signaling and increasing cyclic GMP (cGMP, a chemical messenger that relaxes smooth muscle). Sexual stimulation is still required for an erection to occur. This medicine does not increase sexual desire, and it does not prevent sexually transmitted infections.

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The treatment can also lower blood pressure slightly because the same blood-vessel effects occur elsewhere in the body. That is why medical history and a complete medication list matter, especially for people who use nitrates, certain blood-pressure drugs, or medications that affect sildenafil metabolism. Effects can vary based on age, liver or kidney function, and other therapies taken at the same time.

Who It’s For

This medication is indicated for adults with erectile dysfunction, a condition in which it can be hard to get or keep an erection adequate for sex. ED can have physical and psychological contributors, including vascular disease, diabetes, hormonal changes, medication effects, and stress. For an overview of the condition and commonly listed treatment options, browse the Erectile Dysfunction hub or related collections in Mens Health and Urology.

A prescription is required for Viagra, and it is not an over-the-counter product. It is not appropriate for people who take nitrates for chest pain, because the combination can cause a dangerous drop in blood pressure. This therapy is also generally avoided with riociguat (a guanylate cyclase stimulator for pulmonary hypertension). People with significant cardiovascular disease, recent heart attack or stroke, severe low blood pressure, or certain rare inherited eye disorders may need additional evaluation before use, based on the official labeling and clinician guidance.

Dosage and Usage

Tablets are taken by mouth as needed before sexual activity, following the prescriber’s instructions. Labeling for sildenafil products typically describes use about 30–60 minutes beforehand, with a limit of one dose per day. A high-fat meal may delay how quickly it starts working for some people. Alcohol can also increase the chance of dizziness or lightheadedness, particularly in combination with other blood-pressure–lowering medicines.

When required, prescriptions are confirmed with the prescriber before the pharmacy dispenses medication.

Dose selection is individualized. Many labels describe a typical starting dose, with adjustments based on response, side effects, older age, kidney or liver impairment, and use of interacting drugs (for example, strong CYP3A4 inhibitors). Follow the directions provided with Viagra exactly, and do not combine it with other PDE5 inhibitors unless a prescriber specifically instructs otherwise.

Strengths and Forms

This therapy is supplied as oral tablets. For the brand product, commonly marketed strengths include 25 mg, 50 mg, and 100 mg film-coated tablets. Generic versions may be labeled as sildenafil citrate tablets, and the listed strengths and tablet appearance can differ by manufacturer. Availability can vary by dispensing pharmacy and by regulatory sourcing.

Mens Health Articles and Urology Articles provide broader context on sexual health and related conditions. Those guides can be useful for understanding terminology (for example, “PDE5 inhibitor”) and for organizing questions to discuss with a healthcare professional.

Storage and Travel Basics

Store tablets at controlled room temperature, protected from excess heat and moisture. Keep the medicine in its original packaging until use so the label and expiration date remain available for reference. Do not store tablets in a bathroom cabinet if humidity is high, and do not leave them in a hot car where temperatures can rise quickly.

For travel, carry the medication in a labeled container and keep it out of reach of children and pets. If using a pill organizer, retain the original package in the same bag so the drug name and strength are easy to verify if needed. If a tablet looks discolored, crumbles unusually, or has been exposed to water, it should not be used and the dispensing pharmacy should be contacted for guidance.

Side Effects and Safety

Common side effects with sildenafil can include headache, facial flushing, nasal congestion, indigestion, nausea, dizziness, and visual changes (such as a blue tint or increased light sensitivity). These effects are often dose-related and may be more noticeable when combined with alcohol or other medicines that lower blood pressure. Because ED can coexist with metabolic conditions, some people also want background reading on diabetes-related sexual health, such as Diabetes And Erectile Dysfunction and Diabetes Complications.

Serious adverse events are uncommon but require urgent attention. Seek emergency care for chest pain, severe fainting, sudden vision loss, sudden hearing decrease, stroke-like symptoms, or signs of anaphylaxis (severe allergic reaction) such as swelling of the face or throat. Priapism (a prolonged erection lasting more than four hours) is a medical emergency that can cause permanent injury if not treated promptly. These warnings are part of why clinician screening matters before initiating therapy.

Why it matters: Some symptoms can signal dangerous low blood pressure or heart strain.

Viagra is not intended to be used for multiple doses in a short time window, and it should not be taken with other ED medicines unless a prescriber directs it. People with bleeding disorders, active peptic ulcer disease, significant liver disease, or severe kidney disease may require extra caution. Report any unexpected or persistent side effects to a healthcare professional and follow the official product labeling for detailed warnings.

Drug Interactions and Cautions

The most critical interaction is with nitrates (such as nitroglycerin tablets, sprays, patches, or recreational “poppers” containing amyl nitrite). Combining these can cause a rapid, severe blood pressure drop. Riociguat is another contraindicated combination because it can also amplify blood-pressure lowering. Caution is also advised with alpha-blockers used for urinary symptoms or blood pressure, since additive hypotension can occur, especially when starting or changing doses.

Many medicines can raise sildenafil levels by slowing its breakdown, including some antifungals, macrolide antibiotics, and HIV protease inhibitors. Grapefruit products may also increase exposure for some people. Other therapies may reduce effectiveness, or increase side effects, depending on the individual. Viagra should not be used at the same time as other PDE5 inhibitors, and clinicians may advise limits on alcohol use. For broader reading on how chronic conditions can affect sexual function, see Diabetes And Sexual Health.

Quick tip: Keep an updated medication list for interaction screening.

People using blood-pressure medicines should be aware that lightheadedness can occur, particularly when standing up quickly. If dizziness, fainting, or palpitations occur, medical assessment is appropriate. Always disclose supplements and non-prescription products as well, since some can affect blood pressure or interact through metabolic pathways.

Compare With Alternatives

Several options exist for erectile dysfunction management. Other PDE5 inhibitors include tadalafil and vardenafil, which differ in onset and duration. Some people prefer tadalafil because its longer duration may allow more flexibility, while others prefer a shorter-acting option. Choice depends on medical history, side-effect tolerance, interactions, and prescriber preference.

Brand and generic sildenafil have the same active ingredient, but may differ in tablet appearance and packaging. A clinician may also discuss non-oral approaches, such as vacuum erection devices, urethral suppositories, intracavernosal injections, or counseling when psychological factors contribute. For related reading on intimacy and chronic disease, see Navigating Intimacy With Diabetes. A comparable prescription option in this category is Cialis Tablets, which contains tadalafil.

Pricing and Access

Access depends on having an appropriate prescription and completing the required documentation. CanadianInsulin facilitates cross-border referral and fulfillment through licensed partner pharmacies, which can be relevant for people using cash-pay rather than insurance coverage. If a prescriber changes the dose or discontinues therapy, the order details should be updated to match the current prescription information.

Licensed Canadian pharmacies dispense medications after prescription documentation is reviewed.

For those comparing costs across options, factors that can affect overall pricing include tablet strength, quantity, and whether a brand or generic is prescribed. If the site is running standard offers, details are listed on the Promotions page. Viagra remains a prescription-only medicine, so eligibility and safety screening remain central even when focusing on affordability.

Additional background on diabetes-related sexual function is available in Link Between Diabetes And ED and Signs Of Uncontrolled Diabetes.

Authoritative Sources

For official prescribing details and warnings, consult these references and follow the most current product labeling provided with the medication.

FDA-approved prescribing information (PDF) is available here: FDA Prescribing Information (PDF).

For patient-focused medication basics, see: MedlinePlus Sildenafil.

For European regulatory review and product information, see: EMA Product Information.

To submit a prescription request through the site, select prompt, express, cold-chain shipping when available at checkout.

This content is for informational purposes only and is not a substitute for professional medical advice.