Chiropraxis für Kleintiere Dr. med. vet. Iris Schwager

43 Oral Sildenafil in the Treatment of Erectile Dysfunction

Sildenafil > oral sildenafil


Keep a written list of all of the prescription and nonprescription (over-the-counter) medicines, vitamins, minerals, and dietary supplements you are taking. Bring this list with you each time you visit a doctor or if you are admitted to the hospital.

  • Take sildenafil on an empty stomach for faster absorption.
  • High-fat meals may delay the effectiveness of the medication.
  • Do not crush or chew sildenafil tablets; swallow whole.

You should carry the list with you in case of emergencies.

Information & Authors

tell your doctor and pharmacist what prescription and nonprescription medications, vitamins, and nutritional supplements you are taking or plan to take. Your doctor may need to change the doses of your medications or monitor you carefully for side effects. you should know that sildenafil is available under the brand names Liqrev, Revatio, and Viagra. You should only be treated with one of these products at a time. The following nonprescription or herbal products may interact with sildenafil: cimetidine (Tagamet HB), St.

What is sildenafil used for?

John's wort. Be sure to let your doctor and pharmacist know that you are taking these medications before you start taking sildenafil. Do not start these medications while taking sildenafil without discussing it with your healthcare provider. tell your doctor if you smoke, if you have had heart surgery within the last 6 months, if you have ever had an erection that lasted for more than 4 hours, and if you have recently lost a large amount of body fluids (dehydration). This can happen if you are sick with fever, diarrhea, or vomiting; sweat a lot; or do not drink enough liquids. Department of Medicine, Hospital of the University of Pennsylvania, Philadelphia, PA 19104, USA DOI: 10.1016/S0140-6736(05)60375-3 External LinkAlso available on ScienceDirect External Link The study by I Goldstein and colleagues1 provides the much needed data for scrutiny by the medical community with regard to the efficacy, mechanism of action, pharmacokinetics, dosing, and side-effects of sildenafil.

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Since its approval by the Food and Drug Administration on March 27, 1998, sildenafil (marketed by Pfizer as Viagra) has been a pharmaceutical phenomenon.

Medication Type Potential Interaction Effect Notes
Nitrates Severe hypotension Dangerous drop in blood pressure Absolute contraindication
Alpha-blockers Enhanced hypotensive effect Blood pressure may drop too low Use with caution, monitor BP
CYP3A4 inhibitors Increased sildenafil levels Increased risk of side effects Dose adjustment may be needed
Rifampin Reduced sildenafil effectiveness Lower plasma levels May require dose increase

Its appeal stems from the fact that sildenafil is the first effective and safe oral therapy for men with erectile dysfunction.1–4 Pfizer's stock has risen by 50%, primarily because of aggressive marketing and the tremendous expectations for sildenafil.3 New prescriptions have increased almost exponentially—from 546 in the week ending April 3, to 269 842 in the week ending May 1.3 Urologists and nonurologists alike have been swamped with requests for the drug.

Metrics & Citations

Talk to your doctor about eating grapefruit and drinking grapefruit juice while taking this medicine. If you are taking sildenafil for erectile dysfunction, you are unlikely to miss a dose since this medication is taken as needed, not on a regular dosing schedule. If you are taking sildenafil for PAH, take the missed dose as soon as you remember it. However, if it is almost time for the next dose, skip the missed dose and continue your regular dosing schedule. Do not take a double dose to make up for a missed one.

International Journal of Impotence Research

numbness, burning, or tingling in the arms, hands, feet, or legs pain in muscles, back, arms, or legs changes in color vision (seeing a blue tinge on objects or having difficulty telling the difference between blue and green) sudden severe loss of vision (see below for more information) erection that is painful or lasts longer than 4 hours rash; itching; hives; difficulty breathing or swallowing; swelling of the eyes, face, throat, tongue, or lips Some patients experienced a sudden loss of some or all of their vision after they took sildenafil or other medications that are similar to sildenafil. The vision loss was permanent in some cases. It is not known if the vision loss was caused by the medication. If you experience a sudden loss of vision while you are taking sildenafil, call your doctor immediately. Do not take any more doses of sildenafil or similar medications such as tadalafil (Cialis) or vardenafil (Levitra) until you talk to your doctor. The associated media frenzy has been fuelled by endorsements from prominent individuals.

Database of Abstracts of Reviews of Effects (DARE): Quality-assessed Reviews [Internet].

There have been reports of heart attack, stroke, irregular heartbeat, bleeding in the brain or lungs, high blood pressure, and sudden death in men who took sildenafil for erectile dysfunction. Most, but not all, of these people had heart problems before taking sildenafil. It is not known whether these events were caused by sildenafil, sexual activity, heart disease, or a combination of these and other causes. Talk to your doctor about the risks of taking sildenafil. Some patients experienced a sudden decrease or loss of hearing after they took sildenafil or other medications that are similar to sildenafil.

Pregnancy Categories

It is not known if the hearing loss was caused by the medication. If you experience a sudden loss of hearing, sometimes with ringing in the ears or dizziness, while you are taking sildenafil, call your doctor immediately. If you are taking sildenafil (Viagra) for erectile dysfunction, do not take any more doses of sildenafil (Viagra) or similar medications such as tadalafil (Cialis) sildenafil 100mg blue pill or vardenafil (Levitra) until you talk to your doctor. If you are taking sildenafil (Liqrev, Revatio) for PAH, do not stop taking your medication until you talk to your doctor. Call your doctor if you have any unusual problems while you are taking this medication. Such reports stoke the already intense public demand for information about and prescriptions for sildenafil. In the midst of these developments, it is crucial to recognise and deal with the potential problems.

Condition Caution / Notes Risk Factors
Cardiovascular disease Use with caution Heart failure, recent MI
Concomitant nitrate use Absolute contraindication Risk of severe hypotension
Severe hepatic impairment May require dose adjustment Reduced clearance
Retinitis Pigmentosa Cautious use Potential for vision disturbances

First, sildenafil is no panacea; not all patients with erectile dysfunction will benefit from it.

  • The medication may cause a sudden decrease in blood pressure in some users.
  • Use sildenafil cautiously if you are also taking blood pressure medications.
  • Do not share your medication with others to prevent misuse.

Second, there is substantial risk that many patients will receive little or no evaluation before treatment; the potential for ill-informed and inappropriate prescribing is high.4 Third, sildenafil is not an aphrodisiac,3,4 nor does it increase sexual desire or libido.1–4 The drug has the potential for abuse by thrill-seekers.

  • Sildenafil is sometimes used off-label for other medical conditions.
  • Continuous use without medical supervision is not recommended.
  • Follow your provider's instructions for frequency of use.

Fourth, the known side-effects may not be transient, as current data suggest.

Assessment of study quality

If you experience a serious side effect, you or your doctor may send a report to the Food and Drug Administration's (FDA) MedWatch Adverse Event Reporting program online ( or by phone (1-800-332-1088). Keep this medication in the container it came in, tightly closed, and out of reach of children. Store the tablets at room temperature and away from excess heat and moisture (not in the bathroom). Store the suspension at room temperature or in a refrigerator, but do not freeze it. Dispose of any unused suspension after 60 days.

The effects of diabetes on male sexual function

Keep all medication out of sight and reach of children as many containers are not child-resistant. Place the medication in a safe location – one that is up and away and out of their sight and reach. Dispose of unneeded medications in a way so that pets, children, and other people cannot take them. Do not flush this medication down the toilet. Talk to your pharmacist about take-back programs in your community. Sildenafil may also have other, as-yet-unknown, adverse effects that will become evident only over time.

Parameter Description Typical Value Notes
Absorption Rate How quickly sildenafil enters bloodstream Rapid Peaks in 30-120 minutes
Bioavailability Percentage of dose reaching systemic circulation ~40% Affected by food intake
Half-life Time for plasma concentration to reduce by half 3-5 hours Determines dosing frequency
Peak Plasma Concentration Maximum concentration after dose 1 hour Influenced by gastric emptying and food intake

In the first few weeks after sildenafil's release, physicians' only information source was the package insert.2 Goldstein's study1 supplied data that physicians should use to make informed decisions in the work-up and treatment of patients with erectile dysfunction.

Where to buy Sildenafil Citrate

Visit sildenafil softgel capsule the FDA's Safe Disposal of Medicines website for more information. In case of overdose, call the poison control helpline at 1-800-222-1222. Information is also available online at If the victim has collapsed, had a seizure, has trouble breathing, or can't be awakened, immediately call emergency services at 911. Do not let anyone else take your medication. Ask your pharmacist any questions you have about refilling your prescription. Physicians who prescribe sildenafil should do so only after a comprehensive work-up (history and physical examination, with diagnostic tests if indicated) has been completed.

Frequently asked questions

Also tell your doctor if you have or have ever had pulmonary veno-occlusive disease (PVOD; blockage of veins in the lungs); a stomach ulcer; heart, kidney, or liver disease; a heart attack; heart failure; angina (chest pain); an irregular heartbeat; a stroke; chest pain; high or low blood pressure; high cholesterol; a bleeding disorder; blood circulation problems; blood cell problems such as sickle cell anemia (a disease of the red blood cells), multiple myeloma (cancer of the plasma cells), or leukemia (cancer of the white blood cells); conditions affecting the shape of the penis (e.g., angulation, cavernosal fibrosis, or Peyronie's disease); or diabetes. Also tell your doctor if you or any of your family members have or have ever had an eye disease such as retinitis pigmentosa (an inherited eye condition that causes loss of vision) or if you have ever had sudden severe vision loss, especially if you were told that the vision loss was caused by a blockage of blood flow to the nerves that help you see. if you are a woman and you are taking sildenafil to treat PAH, tell your doctor if you are pregnant, plan to become pregnant, or are breastfeeding. If you become pregnant while taking sildenafil, call your doctor. if you are having surgery, including dental surgery, tell your doctor or dentist that you are taking sildenafil.

Serious Side Effects (Rare)

if you are taking sildenafil to treat erectile dysfunction, tell your doctor if you have ever been advised by a healthcare professional to avoid sexual activity for medical reasons or if you have ever experienced chest pain during sexual activity. Sexual activity may be a sildenafil citrate 100mg tablets strain on your heart, especially if you have heart disease. If you experience chest pain, dizziness, or nausea during sexual activity, call your doctor immediately and avoid sexual activity until your doctor tells you otherwise. tell all your healthcare providers that you are taking sildenafil. If you ever need emergency medical treatment for a heart problem, the healthcare providers who treat you will need to know when you last took sildenafil. Oral sildenafil in the treatment of erectile dysfunction

  • Sildenafil's effects typically last for 4-6 hours.
  • It does not increase sexual desire but enhances response.
  • Onset of action can be affected by age and health status.