Precautions Before Taking Sildenafil Medication

Our guide to maintaining an erection naturally shares techniques to reduce your risk of ED and enjoy better sex. Learn more about how to take sildenafil in our guide. Most side effects of sildenafil are mild, and it’s uncommon for them to persist longer than the medication is active in your body. However, in rare cases, sildenafil treatment can cause more severe or bothersome side effects.

Condition	Ideal Range	Additional Notes
Temperature	15°C to 30°C	Avoid extreme heat or cold
Humidity	Low humidity	Keep in dry place
Light	Keep away from direct sunlight	Protect from light
Packaging	Original packaging, airtight	Prevent moisture exposure

Like most medications, side effects are generally more likely at higher doses than lower doses. For instance, in clinical trials of sildenafil, 16 percent of men reported headaches (the most common side effect) at a dosage of 25mg, compared to 28 percent at 100mg and seven percent who took a placebo.

• Sildenafil helps improve erections by relaxing penile muscles.
• The drug's popularity increased rapidly after approval in the late 1990s.
• It is part of a class of medications called PDE5 inhibitors.
• Sildenafil's development marked a breakthrough for men's health.
• There are ongoing studies to expand sildenafil's therapeutic uses.
• Regular medical check-ups are advised for long-term sildenafil use.
• Generic sildenafil has made treatment more affordable worldwide.
• It’s crucial to adhere to prescribed doses to avoid adverse effects.
• The medication is often taken about 30 minutes before sexual activity.
• Using sildenafil responsibly can improve quality of life for many men.

Vision changes (blurred vision or changes in color perception) Vision changes (blurred vision or changes in color perception) Our blog goes over all the possible sildenafil side effects in more detail. Although rare, sildenafil can cause more serious side effects that may need immediate medical attention. Eye problems like blurred vision or sudden, severe loss of vision Eye problems like blurred vision or sudden, severe loss of vision Serious cardiovascular disease — often in people with preexisting risk factors, such as stroke, ventricular arrhythmia (abnormal heartbeat), or heart attack Serious cardiovascular disease — often in people with preexisting risk factors, such as stroke, ventricular arrhythmia (abnormal heartbeat), or heart attack In very rare cases, sildenafil may also cause priapism — a prolonged and painful erection that may last four hours or longer. Priapism is considered a medical emergency, so seek medical attention as soon as you can to avoid damaging the erectile tissue inside your penis. With that said, be cautious when taking sildenafil if you have Peyronie’s disease (scar tissue in the penis) or another deformation of the penis that may increase your risk of priapism. Sildenafil and other PDE5 inhibitor medications can interact with other drugs.

Brand names

With that said, be cautious when taking sildenafil if you have Peyronie’s disease (scar tissue in the penis) or another deformation of the penis that may increase your risk of priapism. Sildenafil and other PDE5 inhibitor medications can interact with other drugs. In particular, sildenafil is known to interact with: Ritonavir and other CYP3A4 inhibitors, such as the antifungals ketoconazole, itraconazole, and erythromycin Ritonavir and other CYP3A4 inhibitors, such as the antifungals ketoconazole, itraconazole, and erythromycin As such, you shouldn’t take sildenafil or brand-name Viagra if you use nitroglycerin or similar prescription organic nitrates. You also shouldn’t mix sildenafil with recreational drugs called “poppers“ that contain nitrites. Weirdly, grapefruit juice can change the concentrations of PDE5 inhibitors in your body, sildenafil citrate tablets 200mg so you’ll want to avoid it while taking sildenafil.

Before taking sildenafil,

Learn more about sildenafil drug interactions in our guide. It’s best to seek medical advice from a healthcare professional about any medications or supplements you currently take or have recently taken before starting sildenafil. Also, be sure to mention any underlying medical conditions you have, including: Heart problems like pulmonary arterial hypertension, angina, or an irregular heartbeat Heart problems like pulmonary arterial hypertension, angina, or an irregular heartbeat A blood disease like leukemia or sickle cell anemia A blood disease like leukemia or sickle cell anemia The more you tell your healthcare provider, the better they’ll be able to assess your personal risk of side effects and make sure you’re safe while using sildenafil. Sildenafil comes in several dosages, but for ED, it ranges from 25 to 100mg. Your healthcare provider may prescribe sildenafil at a dosage of 100mg if you have moderate to severe erectile dysfunction or if you don’t experience any improvements at a lower dosage. In particular, sildenafil is known to interact with: Ritonavir and other CYP3A4 inhibitors, such as the antifungals ketoconazole, itraconazole, and erythromycin Ritonavir and other CYP3A4 inhibitors, such as the antifungals ketoconazole, itraconazole, and erythromycin As such, you shouldn’t take sildenafil or brand-name Viagra if you use nitroglycerin or similar prescription organic nitrates.

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You also shouldn’t mix sildenafil with recreational drugs called “poppers“ that contain nitrites.

Key takeaways about sildenafil

Hims & Hers has strict sourcing guidelines to ensure our content is accurate and current. We rely on peer-reviewed studies, academic research institutions, and medical associations. We strive to use primary sources and refrain from using tertiary references. Bachelor of Arts, Egyptian and Ancient Western Asian Archaeology - Brown University College, 2011 Bachelor of Arts, Egyptian and Ancient Western Asian Archaeology - Brown University College, 2011 Doctor of Medicine - Brown University Warren Alpert Medical School, 2017 Doctor of Medicine - Brown University Warren Alpert Medical School, 2017 Master of Public Health - Columbia University Mailman School of Public Health, 2018 Master of Public Health - Columbia University Mailman School of Public Health, 2018 Master of Liberal Arts, Journalism - Harvard University Harvard Extension School, 2022 Master of Liberal Arts, Journalism - Harvard University Harvard Extension School, 2022 Master of Science, Healthcare Leadership - Cornell University Weill Cornell Graduate School of Medical Sciences, 2024 Master of Science, Healthcare Leadership - Cornell University Weill Cornell Graduate School of Medical Sciences, 2024 Master of Business Administration - Cornell University Samuel Curtis Johnson Graduate School of Management, 2024 Master of Business Administration - Cornell University Samuel Curtis Johnson Graduate School of Management, 2024 Internship - NYU Grossman School of Medicine Internal Medicine Residency—Community Health Track, 2019 Internship - NYU Grossman School of Medicine Internal Medicine Residency—Community Health Track, 2019 Certified in Public Health - National Board of Public Health Examiners, 2018 Certified in Public Health - National Board of Public Health Examiners, 2018 Medical Writer Certified - American Medical Writers Association, 2020 Medical Writer Certified - American Medical Writers Association, 2020 Editor in the Life Sciences - Board of Editors in the Life Sciences, 2020 Editor in the Life Sciences - Board of Editors in the Life Sciences, 2020 Certified Personal Trainer - National Academy of Sports Medicine, 2022 Certified Personal Trainer - National Academy of Sports Medicine, 2022 Certified Nutrition Coach - National Academy of Sports Medicine, 2023 Certified Nutrition Coach - National Academy of Sports Medicine, 2023 Board Certified Medical Affairs Specialist - Accreditation Council for Medical Affairs, 2023 Board Certified Medical Affairs Specialist - Accreditation Council for Medical Affairs, 2023 Certificate of Advanced Education in Obesity Medicine - Obesity Medicine Association, 2025 Certificate of Advanced Education in Obesity Medicine - Obesity Medicine Association, 2025 Regulatory Affairs Certification - Regulatory Affairs Professionals Society, 2025 Regulatory Affairs Certification - Regulatory Affairs Professionals Society, 2025 Medical Expert Board Member - Eat This, Not That!, 2021– Medical Expert Board Member - Eat This, Not That!, 2021– Title: Individuals' Perceptions of the Efficacy, Quality, and Safety of Care Accessed via a Telemedicine Platform: A Retrospective Analysis of Survey Data Published in: Telemedicine Journal and E-Health Date: 2026 URL: Title: Individuals' Perceptions of the Efficacy, Quality, and Safety of Care Accessed via a Telemedicine Platform: A Retrospective Analysis of Survey Data Published in: Telemedicine Journal and E-Health Published in: Telemedicine Journal and E-Health Title: Biomechanical evaluation of a novel suturing scheme for grafting load-bearing collagen scaffolds for rotator cuff repair Published in: Clinical Biomechanics Date: 2015 URL: Title: Biomechanical evaluation of a novel suturing scheme for grafting load-bearing collagen scaffolds for rotator cuff repair Title: Pelvic incidence and acetabular version in slipped capital femoral epiphysis Published in: Journal of Pediatric Orthopaedics Date: 2015 Title: Pelvic incidence and acetabular version in slipped capital femoral epiphysis Title: Relationship between pelvic incidence and osteoarthritis of the hip Published in: Bone & Joint Research Date: 2016 URL: Title: Relationship between pelvic incidence and osteoarthritis of the hip Title: Effects of PDGF-BB delivery from heparinized collagen sutures on the healing of lacerated chicken flexor tendon in vivo Published in: Acta Biomaterialia Date: 2017 URL: Title: Effects of PDGF-BB delivery from heparinized collagen sutures on the healing of lacerated chicken flexor tendon in vivo Dr. Bohl’s medical expertise is regularly featured in consumer health media: Eat This, Not That!

Most Asked Questions

: Contributor and Medical Expert Board Member on nutrition and wellness topics The Dr. Oz Show: Behind-the-scenes contributor to Emmy Award-winning health segments Sharecare: Public-facing health writer, simplifying complex medical issues for millions of readers Dr. Bohl’s medical expertise is regularly featured in consumer health media: : Contributor and Medical Expert Board Member on nutrition and wellness topics : Contributor and Medical Expert Board Member on nutrition and wellness topics The Dr. Oz Show: Behind-the-scenes contributor to Emmy Award-winning health segments The Dr. Weirdly, grapefruit juice can change the concentrations of PDE5 inhibitors in your body, sildenafil citrate tablets 200mg so you’ll want to avoid it while taking sildenafil. Learn more about sildenafil drug interactions in our guide. It’s best to seek medical advice from a healthcare professional about any medications or supplements you currently take or have recently taken before starting sildenafil. Also, be sure to mention any underlying medical conditions you have, including: Heart problems like pulmonary arterial hypertension, angina, or an irregular heartbeat Heart problems like pulmonary arterial hypertension, angina, or an irregular heartbeat A blood disease like leukemia or sickle cell anemia A blood disease like leukemia or sickle cell anemia The more you tell your healthcare provider, the better they’ll be able to assess your personal risk of side effects and make sure you’re safe while using sildenafil. Sildenafil comes in several dosages, but for ED, it ranges from 25 to 100mg. Your healthcare provider may prescribe sildenafil at a dosage of 100mg if you have moderate to severe erectile dysfunction or if you don’t experience any improvements at a lower dosage. Here’s what to keep in mind: Sildenafil might be a more effective ED treatment at higher dosages, but it could also cause more side effects.

Dose (mg)	Typical Usage	Onset Time (minutes)	Duration (hours)
25	Mild ED	30	4
50	Moderate ED	30-60	4-6
100	Severe ED	30-60	4-6
20	Off-label use	45	4

Sildenafil might be a more effective ED treatment at higher dosages, but it could also cause more side effects. Let your healthcare provider know if you experience any issues while using sildenafil to treat ED, including side effects or drug interactions. If you do experience adverse effects with sildenafil that outweigh the benefits of taking it, you may benefit from trying another PDE5 inhibitor, such as Stendra® (avanafil), tadalafil (Cialis®), or vardenafil (previously sold as Levitra®). We offer sildenafil and several other ED medications online, following an online ED consultation with a licensed healthcare provider who’ll determine if a prescription is appropriate.

Adverse effects

Here’s what to keep in mind: Sildenafil might be a more effective ED treatment at higher dosages, but it could also cause more side effects. Sildenafil might be a more effective ED treatment at higher dosages, but it could also cause more side effects. Let your healthcare provider know if you experience any issues while using sildenafil to treat ED, including side effects or drug interactions. If you do experience adverse effects with sildenafil that outweigh the benefits of taking it, you may benefit from trying another PDE5 inhibitor, such as Stendra® (avanafil), tadalafil (Cialis®), or vardenafil (previously sold as Levitra®). We offer sildenafil and several other ED medications online, following an online ED consultation with a licensed healthcare provider who’ll determine if a prescription is appropriate.

Related Drugs

Interested in finding out more before you get started? Our guide to the most common treatments for erectile dysfunction goes into detail about the buy sildenafil citrate online canada most effective options, from sildenafil to other FDA-approved medications. Sildenafil: from angina to erectile dysfunction to pulmonary hypertension and beyond. A systematic review of sildenafil mortality through the years. National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK). Interested in finding out more before you get started?

• Sildenafil has been shown to aid men with diabetes-related ED.
• The drug may also reduce blood pressure temporarily.
• Some men may not respond to sildenafil due to various health factors.
• It is recommended to take sildenafil on an empty stomach for faster effects.
• Overdose symptoms include dizziness, fainting, and pain in the chest.
• Sildenafil should not be used with other erectile dysfunction medications simultaneously.
• Patients should inform their doctor if they experience prolonged erections.
• Certain medical conditions require cautious use of sildenafil.
• The medication can sometimes cause changes in color perception.
• Always check the expiration date before using sildenafil pills.

Our guide to the most common treatments for erectile dysfunction goes into detail about the buy sildenafil citrate online canada most effective options, from sildenafil to other FDA-approved medications. Sildenafil: from angina to erectile dysfunction to pulmonary hypertension and beyond. A systematic review of sildenafil mortality through the years.

How it works

Your questions answered

National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK). Hims & Hers has strict sourcing guidelines to ensure our content is accurate and current.

• Sildenafil is a phosphodiesterase type 5 (PDE5) inhibitor.
• The drug was first approved by the FDA in 1998.
• It can be purchased online but requires a prescription in most countries.
• Generic versions of sildenafil are typically cheaper than brand-name Viagra.
• Proper storage involves keeping it at room temperature away from moisture.
• Sildenafil does not protect against sexually transmitted diseases.
• Lifestyle changes like exercise and healthy eating can enhance results.
• Combining sildenafil with other ED treatments should be discussed with a doctor.
• It's important to inform your doctor about all medications you take.
• Sildenafil is not an aphrodisiac and requires sexual stimulation to work.

We rely on peer-reviewed studies, academic research institutions, and medical associations. We strive to use primary sources and refrain from using tertiary references.

Side Effects

Our guide to maintaining an erection naturally shares techniques to reduce your risk of ED and enjoy better sex. Learn more about how to take sildenafil in our guide. Most side effects of sildenafil are mild, and it’s uncommon for them to persist longer than the medication is active in your body. However, in rare cases, sildenafil treatment can cause more severe or bothersome side effects. Like most medications, side effects are generally more likely at higher doses than lower doses.

Organic Nitrates, Nitrites, and Nitric Oxide Donors

For instance, in clinical trials of sildenafil, 16 percent of men reported headaches (the most common side effect) at a dosage of 25mg, compared to 28 percent at 100mg and seven percent who took a placebo. Vision changes (blurred vision or changes in color perception) Vision changes (blurred vision or changes in color perception) Our blog goes over all the possible sildenafil side effects in more detail. Although rare, sildenafil can cause more serious side effects that may need immediate medical attention. Eye problems like blurred vision or sudden, severe loss of vision Eye problems like blurred vision or sudden, severe loss of vision Serious cardiovascular disease — often in people with preexisting risk factors, such as stroke, ventricular arrhythmia (abnormal heartbeat), or heart attack Serious cardiovascular disease — often in people with preexisting risk factors, such as stroke, ventricular arrhythmia (abnormal heartbeat), or heart attack In very rare cases, sildenafil may also cause priapism — a prolonged and painful erection that may last four hours or longer. Priapism is considered a medical emergency, so seek medical attention as soon as you can to avoid damaging the erectile tissue inside your penis. Bachelor of Arts, Egyptian and Ancient Western Asian Archaeology - Brown University College, 2011 Bachelor of Arts, Egyptian and Ancient Western Asian Archaeology - Brown University College, 2011 Doctor of Medicine - Brown University Warren Alpert Medical School, 2017 Doctor of Medicine - Brown University Warren Alpert Medical School, 2017 Master of Public Health - Columbia University Mailman School of Public Health, 2018 Master of Public Health - Columbia University Mailman School of Public Health, 2018 Master of Liberal Arts, Journalism - Harvard University Harvard Extension School, 2022 Master of Liberal Arts, Journalism - Harvard University Harvard Extension School, 2022 Master of Science, Healthcare Leadership - Cornell University Weill Cornell Graduate School of Medical Sciences, 2024 Master of Science, Healthcare Leadership - Cornell University Weill Cornell Graduate School of Medical Sciences, 2024 Master of Business Administration - Cornell University Samuel Curtis Johnson Graduate School of Management, 2024 Master of Business Administration - Cornell University Samuel Curtis Johnson Graduate School of Management, 2024 Internship - NYU Grossman School of Medicine Internal Medicine Residency—Community Health Track, 2019 Internship - NYU Grossman School of Medicine Internal Medicine Residency—Community Health Track, 2019 Certified in Public Health - National Board of Public Health Examiners, 2018 Certified in Public Health - National Board of Public Health Examiners, 2018 Medical Writer Certified - American Medical Writers Association, 2020 Medical Writer Certified - American Medical Writers Association, 2020 Editor in the Life Sciences - Board of Editors in the Life Sciences, 2020 Editor in the Life Sciences - Board of Editors in the Life Sciences, 2020 Certified Personal Trainer - National Academy of Sports Medicine, 2022 Certified Personal Trainer - National Academy of Sports Medicine, 2022 Certified Nutrition Coach - National Academy of Sports Medicine, 2023 Certified Nutrition Coach - National Academy of Sports Medicine, 2023 Board Certified Medical Affairs Specialist - Accreditation Council for Medical Affairs, 2023 Board Certified Medical Affairs Specialist - Accreditation Council for Medical Affairs, 2023 Certificate of Advanced Education in Obesity Medicine - Obesity Medicine Association, 2025 Certificate of Advanced Education in Obesity Medicine - Obesity Medicine Association, 2025 Regulatory Affairs Certification - Regulatory Affairs Professionals Society, 2025 Regulatory Affairs Certification - Regulatory Affairs Professionals Society, 2025 Medical Expert Board Member - Eat This, Not That!, 2021– Medical Expert Board Member - Eat This, Not That!, 2021– Title: Individuals' Perceptions of the Efficacy, Quality, and Safety of Care Accessed via a Telemedicine Platform: A Retrospective Analysis of Survey Data Published in: Telemedicine Journal and E-Health Date: 2026 URL: Title: Individuals' Perceptions of the Efficacy, Quality, and Safety of Care Accessed via a Telemedicine Platform: A Retrospective Analysis of Survey Data Published in: Telemedicine Journal and E-Health Published in: Telemedicine Journal and E-Health Title: Biomechanical evaluation of a novel suturing scheme for grafting load-bearing collagen scaffolds for rotator cuff repair Published in: Clinical Biomechanics Date: 2015 URL: Title: Biomechanical evaluation of a novel suturing scheme for grafting load-bearing collagen scaffolds for rotator cuff repair Title: Pelvic incidence and acetabular version in slipped capital femoral epiphysis Published in: Journal of Pediatric Orthopaedics Date: 2015 Title: Pelvic incidence and acetabular version in slipped capital femoral epiphysis Title: Relationship between pelvic incidence and osteoarthritis of the hip Published in: Bone & Joint Research Date: 2016 URL: Title: Relationship between pelvic incidence and osteoarthritis of the hip Title: Effects of PDGF-BB delivery from heparinized collagen sutures on the healing of lacerated chicken flexor tendon in vivo Published in: Acta Biomaterialia Date: 2017 URL: Title: Effects of PDGF-BB delivery from heparinized collagen sutures on the healing of lacerated chicken flexor tendon in vivo Dr. Bohl’s medical expertise is regularly featured in consumer health media: Eat This, Not That!

• Sildenafil is available in different strengths to tailor treatment.
• It is often used in clinical settings for ED diagnosis and management.
• Men taking sildenafil should avoid heavy meals shortly before dosing.
• The drug's effectiveness can be influenced by age and overall health.
• Combining sildenafil with recreational drugs can be dangerous.
• Some users report that sildenafil enhances spontaneous sexual activity.
• It is important to only use sildenafil that has been prescribed by a healthcare provider.
• The medication’s cost varies based on brand, dosage, and pharmacy.
• Sildenafil may cause transient eye color changes due to blood vessel effects.
• Patients should keep track of dosage and side effects experienced.

: Contributor and Medical Expert Board Member on nutrition and wellness topics The Dr. Oz Show: Behind-the-scenes contributor to Emmy Award-winning health segments Sharecare: Public-facing health writer, simplifying complex medical issues for millions of readers Dr. Bohl’s medical expertise is regularly featured in consumer health media: : Contributor and Medical Expert Board Member on nutrition and wellness topics : Contributor and Medical Expert Board Member on nutrition and wellness topics The Dr.

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Sildenafil Citrate	Generic	$1 - $5	Online, pharmacies	Generic form available

Oz Show: Behind-the-scenes contributor to Emmy Award-winning health segments The Dr.