The effects of sildenafil last approximately four hours.8 Vardenafil and sildenafil are similarly effective at treating erectile dysfunction.
Vardenafil is a bit less likely to cause visual color tinge or drop blood pressure than sildenafil, but individual experience varies. Sildenafil kicks in within approximately 30 minutes and lasts about four hours. Vardenafil starts closer to 60 minutes and lasts five to seven hours. Vardenafil (Levitra®) is a medication prescribed to treat erectile dysfunction in men. It belongs to a class of medications called phosphodiesterase (PDE) inhibitors and works by increasing blood flow to the penis during sexual stimulation.
While vardenafil does not cure erectile dysfunction or increase sexual desire, the increased blood flow to the genitals can cause an erection. Vardenafil comes as a rapidly disintegrating oral tablet.2 Recommendations are to take as needed, 60 minutes before sexual activity. The most commonly prescribed dosage is 10 mg once per day as needed.3 Depending on your personal needs and direction from your medical provider, you may be prescribed 5 mg or 20 mg doses. The effects of vardenafil can last anywhere from five to seven hours.4 Vardenafil usually should not be taken more than once every 24 hours. Sildenafil (Viagra®) is a medication used to treat erectile dysfunction in men.
Sildenafil is in a class of medications called phosphodiesterase (PDE) inhibitors which treat erectile dysfunction by increasing blood flow to the penis during sexual stimulation. This increased blood flow can lead to an erection. However, sildenafil cannot cure erectile dysfunction or increase sexual desire. Sildenafil is also prescribed to treat pulmonary arterial hypertension.6 For most patients, the recommended dosage is 50 mg approximately one hour before sexual activity. However, sildenafil can be taken anywhere from 30 minutes to four hours before sexual activity.7 Your medical provider may prescribe a different dosage, depending on your needs, of 20 mg, 25 mg or 100 mg. Both are phosphodiesterase inhibitors; however, vardenafil has been shown to be more potent and more selective than sildenafil at inhibiting phosphodiesterase-5.
| Product | Dosage | Quantity + Bonus | Price | |
|---|---|---|---|---|
| Viagra Generic | 25mg | 360 + 10 Pills | 213.68€ 203.50€ | |
| Kamagra | 100mg | 12 Pills | 55.64€ 52.99€ | |
| Viagra Generic | 50mg | 180 + 8 Pills | 158.82€ 151.26€ | |
| Kamagra | 100mg | 84 + 6 Pills | 264.44€ 251.85€ | |
| Viagra Generic | 200mg | 20 Pills | 61.69€ 58.75€ | |
| Viagra Generic | 100mg | 270 + 10 Pills | 270.47€ 257.59€ | |
| Kamagra Soft Tabs | 100mg | 84 + 4 Pills | 233.05€ 221.95€ | |
| Kamagra | 100mg | 20 Pills | 86.09€ 81.99€ | |
| Viagra Generic | 200mg | 360 + 10 Pills | 481.98€ 459.03€ | |
| Kamagra Soft Tabs | 100mg | 32 Pills | 120.11€ 114.39€ |
Vardenafil does not inhibit phosphodiesterase-6, which has been connected to a rare side effect of sildenafil of altered color perception.9 Sildenafil also acts faster than vardenafil, kicking in as soon as 30 minutes. Vardenafil is effective closer to 60 minutes after ingestion.10 Vardenafil has been shown in studies to be effective for erectile dysfunction in 71% of men under the age of 45, 76% of men aged 45-64 and 85% of men over 65.11 Up to 87% of men in one study with a broad spectrum of participants reported sildenafil had improved their erections compared with 11.3%-41.3% of patients in subgroups receiving a placebo.12 Common sildenafil 50 mg tab side effects of vardenafil include:13 Sildenafil has many of the same side effects as vardenafil like headache, flushing, nasal congestion and nausea/upset stomach.
A few side effects that sildenafil has that aren’t common chew sildenafil with vardenafil include:14 Numbness, burning or tingling in the arms, hands, feet or legs. Numbness, burning or tingling in the arms, hands, feet or legs. Pain in muscles, back, arms or legs.
Oral sildenafil in the treatment of erectile dysfunction. The New England Journal of Medicine, 338(20), 1397–1404. A prospective study of the beneficial effects of dose optimization and customized instructions on patient satisfaction with sildenafil citrate (Viagra) for erectile dysfunction. International Journal of Impotence Research, 18(5), 389–394. Sublingual sildenafil in the treatment of erectile dysfunction: Faster onset of action with less dose.
International Journal of Urology, 11(11), 989–993. Sex, erectile dysfunction, and the heart: A growing problem. Phosphodiesterase‑5 (PDE5) inhibitors in the management of erectile dysfunction. Pharmacy and Therapeutics, 38(7), 407–419. Cardiovascular effects of sildenafil citrate and recommendations for its use.
American Journal of Cardiology, 84(5), 11N–17N. Erectile dysfunction (ED) is a common condition affecting around 40% of men at age 40 and 70% at age 70.1 While you may feel some embarrassment, know that you are not alone and there are effective medications available to you from the privacy of your own home. Vardenafil (Levitra®) and sildenafil (Viagra®) are two commonly prescribed prescription medications for ED. Read on to learn more about how they work, their effectiveness and how much you can expect to pay for each. Both sildenafil white vardenafil and sildenafil are PDE5 inhibitors with overlapping side effects like headache, flushing, nasal congestion and heartburn. Changes in color vision (seeing a blue tinge on objects or having difficulty telling the difference between blue and green).
| Brand/Source | Price per Tablet | Package Size | Cost per Pack | Notes |
|---|---|---|---|---|
| Brand A | $3.00 | 30 tablets | $90.00 | Trademarked, pharmacy purchase |
| Generic B | $0.50 | 60 tablets | $30.00 | FDA-approved generic |
| Online Supplier C | $0.20 | 90 tablets | $18.00 | Bulk purchase, check authenticity |
| Local Pharmacy D | $1.00 | 20 tablets | $20.00 | Over-the-counter available |
Get secure, private treatment online from RedBox Rx with FDA-approved meds starting at $1 per pill.
Physician-Scientist; Founder, Director, and Chief Executive OfficerXYON: Founder, Director, and CEOEducationDoctorate of Medicine (MD) — University of Cape Town, South Africa — 1991Genetics (PhD) — University of Amsterdam, The Netherlands — 1998Internal Medicine (Postgraduate Fellowship) — University of British Columbia (UBC), Canada — 2001Academic & Clinical AppointmentsClinical Assistant Professor, Division of General Internal Medicine — University of British ColumbiaAssociate Member, Division of Cardiology, Department of Medicine — University of British ColumbiaFaculty — Providence Health Care Heart and Lung Institute B., Ströberg, P., Lee, S. W., Park, N. C., Kim, S.-W., Tseng, L.-J., Collins, S., & Stecher, V. J. Sildenafil citrate 100 mg starting dose in men with erectile dysfunction in an international, double-blind, placebo-controlled study: Effect on the sexual experience and reducing feelings of anxiety about the next intercourse attempt.
The Journal of Sexual Medicine, 6(10), 2826–2835. Sildenafil: A review of its use in erectile dysfunction. Effects of two different dosages of sildenafil on patients with erectile dysfunction. American Journal of Men’s Health, 11(3), 747–757. Urologist recommends daily Viagra to prevent impotence.
Goldstein, I., Lue, T. F., Padma-Nathan, H., Rosen, R. C., Steers, W. D., & Wicker, P. A. Negative interactions may occur if the following drugs or substances are consumed while taking vardenafil15 or sildenafil:16 It is not advised to take vardenafil and sildenafil together, as it may cause blood pressure to fall excessively. Additionally, there would be an increased risk of other side effects such as dizziness, lightheadedness, fainting, headache, flushing, heart palpitations and priapism (prolonged and painful erection unrelated to sexual activity).17 The average cost of vardenafil is $30 for two tablets.18 With RedBox Rx, you can get generic vardenafil for as low as $3 per tablet. The average cost of sildenafil is approximately $10 for two tablets.19 With RedBox Rx, you can get generic sildenafil for $5 and as low as $1 per tablet when choosing larger quantities.
| Dosage | Recommended Use | Onset of Action | Duration of Effect | Typical Frequency |
|---|---|---|---|---|
| 10 mg | Mild to moderate ED cases | 30-60 minutes | Up to 4-6 hours | Once per day, as needed |
| 20 mg | Moderate to severe ED | 30-60 minutes | Up to 4-6 hours | Once per day, as needed |
| 5 mg | For elderly or sensitive users | 30-60 minutes | Up to 4 hours | Once per day, as needed |
You can also see how RedBox Rx compares to other online pharmacies in the chart below.
Grapefruit juice is a mild inhibitor of an enzyme known as CYP3A4 and can increase the risk of side effects with sildenafil as this medication is metabolized by CYP3A4 Whether you’re taking 25mg or 100mg, always tell your doctor about any other medications you’re taking, even if they’re over the counter. There is no perfect dosage of sildenafil for every man. 50mg is the most prescribed dose, but depending on the factors discussed in this article there may be a better dose for you based on your specific medical background and needs.FYI: Erectile dysfunction can be a side effect of common hair loss medications like finasteride. If you're also struggling with hair loss and are worried about how treatment could affect performance, you may want to consider topical finasteride. For most healthy adults, the recommended starting sildenafil dosage is 50 mg taken about 30–60 minutes before sexual activity.
Depending on your response and side effects, a doctor may adjust your sildenafil citrate dosage down to 25 mg or up to 100 mg Standard tablets for erectile dysfunction are 25 mg, 50 mg, and 100 mg. A sildenafil 20 mg dosage is primarily manufactured for pulmonary hypertension (Revatio). While 20 mg may help some men—especially in sublingual forms—many patients need higher doses for consistent results Sildenafil is generally intended for on‑demand use, not as a sildenafil daily dosage. Unlike tadalafil, there is no FDA‑approved daily sildenafil regimen. Taking it more than once in 24 hours can increase the risk of side effects and should be avoided unless prescribed by your doctor to be used that way.
Exceeding the maximum dosage for sildenafil (more than 100 mg in 24 hours) does not improve erections and raises the risk of severe headaches, dizziness, low blood pressure, vision changes, and priapism (a prolonged erection requiring emergency care). Seek medical attention if you exceed the recommended daily maximum of 100mg in one day. Both doses work by improving blood flow, but the sildenafil 100 mg dosage is usually prescribed if 50 mg is not effective. Studies show a higher response rate at 100 mg, but also a greater chance of side effects. Doctors typically start at 50 mg and only increase to 100 mg if needed. *Discounts for larger quantities as low as $1.00 per tablet.
| Condition | Risk Factors | Recommendations |
|---|---|---|
| Use with nitrates | Severe hypotension, risk of significant blood pressure drop | Avoid combining, consult healthcare provider |
| Severe cardiovascular disease | Risk of adverse cardiovascular events | Use only under medical supervision |
| Liver impairment | Altered metabolism, increased side effects | Dose adjustment or avoid use |
| Retinitis pigmentosa | Potential for increased visual side effects | Use with caution, consult ophthalmologist |
Both vardenafil20 and sildenafil21 require a prescription.
You can obtain a prescription online for vardenafil and sildenafil. You cannot get vardenafil or sildenafil over the counter. Additionally, the FDA warns against purchasing over-the-counter vardenafil and sildenafil alternatives because they are not regulated and pose health risks like dangerously low blood pressure.22 RedBox Rx only prescribes FDA-approved medications for ED.
RedBox Rx makes obtaining a prescription for ED, like vardenafil or sildenafil, easy and affordable. Transparent, affordable, flat rates for ED medications starting at $1 per tablet.