What is sildenafil?
Sildenafil is a drug from the group of PDE-5 inhibitors used for the treatment of erectile dysfunction. The active ingredient was originally developed by Pfizer and known as Viagra®. Since the patent process in 2013, Sildenafil has also been available as a generic product from various manufacturers.
The drug allows erection during sexual stimulation by improving blood circulation of the penis. Without sexual excitement, Sildenafil does not develop any effect – so it is not an aphrodisiac.
Sildenafil generics contain the same active ingredient as the original product and are subject to the same strict quality requirements. They offer a cost-effective alternative with the same effectiveness and safety.
Active Ingredients & Mechanism of Action
Active ingredient: Sildenafil
Sildenafil belongs to the active substance class of the phosphodiesterase-5-inhibitors (PDE-5-inhibitors). To understand the mode of action, a short look at the erection mechanism is helpful:
In sexual excitation, nitrogen monoxide (NO) is released in the swelling body of the penis. This activates an enzyme which leads to the formation of cyclic guanosine monophosphate (cGMP). cGMP brings about a relaxation of the smooth muscles in the blood vessels of the penis, resulting in more blood and an erection.
The enzyme phosphodiesterase-5 (PDE-5) normally reconstructs cGMP and thus terminates the erection. Sildenafil inhibits this enzyme so that cGMP remains effective for longer. The result: erection can be created more easily and maintained longer.
Important: Sildenafil only works with existing sexual stimulation. No release of nitrogen monoxide takes place without excitation, and the drug cannot develop its effect.
Who is it suitable for?
Sildenafil is suitable for adult men with erectile dysfunction, i.e. the repeated inability to achieve or maintain an erection sufficient for sexual intercourse.
Typical applications:
- erectile dysfunction due to blood circulation disorders
- Erectile dysfunction in diabetes mellitus
- Psychic erection problems
- erectile disorders as an accompanying evidence of other diseases
**Before the application should be clarified:* *
- The cause of erection disorder (organic, mental or mixed)
- Whether cardiovascular diseases are present
- Which other medicines are taken
- Whether counter-indications exist
Available Dosages
Sildenafil is available in various dosage levels:
Current dosages:
- 25 mg – lowest dosage, suitable for men over 65 years or with reduced liver/near function
- 50 mg – standard dose for the start of treatment
- 100 mg – Maximum allowed single dose
Recommendation for dose determination: The usual initial dose is 50 mg. Depending on the efficacy and compatibility, the dose can be increased to 100 mg or reduced to 25 mg. The maximum dose of 100 mg per day should not be exceeded.
Pack sizes: Sildenafil is available in packs with 4, 8, 12 or 24 tablets. The tablets are usually divisible, which allows a flexible dosage.
How to Take
Intake date: Sildenafil should be taken about 30 to 60 minutes before the planned intercourse. The effect can be used after 30 minutes.
Intake with or without food: The tablet can be taken independently of meals. However, a high-fat meal can delay the entry of action. For a faster effect it is recommended to take on sober stomach or after a slight meal.
Activity: The action of Sildenafil lasts about 4 to 6 hours. In this period, erection is possible for sexual stimulation.
Activity: Sildenafil should be taken at most once a day. Between two revenues should be at least 24 hours.
Alcohol: Alcohol in small amounts is possible in principle, but can affect the effectiveness and increase the risk of side effects.
Contraindications
**Sildenafil must not be taken at:* *
- Intake of nitrates or NO donors – these include glycerol trinitrate (nitrospray), isosorbide mononitrate, isosorbide dinitrate and amyl nitrite (Poppers). The combination can lead to a life-threatening drop in blood pressure.
- Black cardiovascular diseases – especially in unstable angina pectoris, recently suffered heart attack (last 90 days), stroke (last 6 months) or severe heart failure
- Low blood pressure (under 90/50 mmHg)
- Certain eye diseases – especially in inherited retinal diseases such as retinitis pigmentosa
- Ingestion of certain drugs – especially strong CYP3A4 inhibitors such as Ritonavir or Ketoconazole
- Oversensitivity against Sildenafil or one of the other components
**Precaution is offered at:* *
- Anatomical penis changes
- diseases that can be associated with prolonged erection (e.g. sickle cell anemia)
- Blood coagulation disorders or active stomach ulcers
Possible Side Effects
Like all medicines, Sildenafil can also cause side effects. Most of the side effects are mild to moderate and sound away from themselves.
**Very common (more than 1 out of 10):* *
- Headaches
- Face redness (Flush)
**Family (1 to 10 of 100):* *
- Blocked nose
- Indigestion
- dizziness
- visual disorders (e.g. blue glazing, increased light sensitivity)
**Current (1 to 10 of 1000):* *
- nausea
- Heart turf
- fatigue
- Skin rash
Selten but to take seriously:
- Priapism (painful erection over more than 4 hours) – immediate medical treatment required
- Sudden hearing loss or visual loss – immediately consult a doctor
Most side effects are dose-dependent and occur less frequently at lower dosages.
Interactions
Important interactions:
- Nitrate and NO donors: Absolutely contraindicated! The combination can cause a dangerous drop in blood pressure.
- Alpha blocker: Simultaneous intake can increase blood pressure-lowering effect. Sildenafil should only be started after a stable alpha blocker therapy.
- CYP3A4 inhibitors: Drugs such as Ritonavir, Ketoconazole, Itraconazole and Erythromycin can increase the sildenafil concentration in the blood. A dose reduction may be required.
- Other PDE 5 inhibitors: No simultaneous use with Tadalafil, Vardenafil or Avanafil.
- Grapefruit juice: Can increase the active ingredient concentration easily.
- Blow pressure lowering medicines: Can increase the blood pressure lowering effect of Sildenafil.
Frequently Asked Questions
Similar Medications
Is sildenafil right for you?
A licensed doctor will review your information and issue a prescription if suitable. Discreet and secure.
Important Notice
This information does not replace medical advice. If you have questions about your health or the suitability of this medication, please consult a doctor. Read the package leaflet before use.