PDE5 Inhibitors: Common ED Drugs And How They Work – Introduction:
ED, the most common form of male degeneration, is a health problem that affects millions of men worldwide. ED is defined as the inability to create or maintain a erection suitable for sex. PDE5 inhibitors have revolutionised the treatment of ED, offering men a safe and effective alternative to it. In this post, I try to provide a detailed insight on what PDE5 inhibitors are, how they work, and why they are important for treating ED.
Mechanism of Action:
PDE5 inhibitors work by boosting the amount of cyclic guanosine monophosphate (cGMP), a chemical that unwinds the smooth muscle of the corpus cavernosum, which allows blood to flow to the penis. This distensification of the smooth muscle facilitates activation of the corpus cavernosum to produce an erection.
PDE5 is an enzyme present in tissues like the corpus cavernosum, lungs, platelets, and vascular smooth muscle. PDE5 is designed to degrade cGMP and suppress its function. PDE5 inhibitors act by deactivating PDE5, thereby raising cGMP levels and increasing smooth muscle relaxation.
Common ED Drugs:
The three most commonly used PDE5 inhibitors for ED are Sildenafil (Viagra), Tadalafil (Cialis) and Vardenafil (Levitra). Such medications vary in their rate of action, duration of action, and side effects, but share similar mechanisms of action.
Sildenafil (Viagra)
The first PDE5 inhibitor to be approved for the treatment of ED was Sildenafil. It begins working very quickly, in as little as 30 minutes, and the effect is around 4 hours long. Sildenafil comes in dosages from 25 to 100mg, which are taken only if required, usually about an hour before sex. Sildenafil’s most frequent side effects include headache, flushing, dyspepsia, and congestion of the nose.
Tadalafil (Cialis)
Tadalafil works more slowly than Sildenafil – 1-2 hours after it hits the plasma threshold. But it does not go away quickly, lasting as long as 36 hours — which makes it an ideal solution for men looking for that longer effect. Tadalafil is available in 5mg to 20mg doses, or as a 2.5mg or 5mg daily capsule. This longer time between onsets enables men to act freely without scheduling the erection of drugs. Some side effects of Tadalafil include headache, dyspepsia, back pain, and myalgia.
Vardenafil (Levitra)
Vardenafil works just like Sildenafil does, within 30 minutes, but it will stay in effect for about 4 to 5 hours. Vardenafil is available in dosages of 5 mg to 20 mg, and is administered as needed, usually an hour before sexual contact. Vardenafil is effective in men with ED following diabetes, spinal cord injury, and radical prostatectomy. Some of the more common side effects of Vardenafil include headache, flushing, dyspepsia, and rhinitis.
Side Effects and Precautions:
Common Side Effects:
The most common side-effects of PDE5 inhibitors are headache, flushing, nose irritation, and dyspepsia. These effects are typically mild and temporary, meaning that they subside automatically over a short time.
Headache is the most commonly reported adverse effect of PDE5 inhibitors and it affects up to one in five men taking these medications. Most headaches are mild and brief, so they resolve themselves within minutes. If the headache should become severe or persistent, then you should seek the advice of a physician.
The second most widespread side-effect is facial flushing, a form of skin redness typically seen in the face and neck. It affects 15 per cent of men on PDE5 inhibitors, but this usually subsides after a few minutes. When this symptom bothers a person or when other symptoms arise, medical treatment is usually sought.
Nausea is a less common symptom and may occur in as much 10% of men on these medications. This is not really a bad side effect, but it’s annoying and affects quality of life. Such symptoms are usually treated with over-the-counter decongestants, but always seek the advice of a physician before taking new medication.
Dyspepsia is indigestion, and is the least common side-effect that can occur in as many men taking PDE5 inhibitors as 7% of men. This can lead to upper abdomen aches, bloating, and vomiting. Most often, these symptoms can be relieved through lifestyle changes like reducing meals to smaller and more frequent ones, as well as avoiding spicy or oily foods. If dyspepsia is severe or persistent, you should consult a doctor.
Cardiovascular Precautions:
PDE5 inhibitors are generally safe for most men, but they should be used sparingly in men with existing cardiovascular disease. This is because sexual activity, often initiated by PDE5 inhibitors, has been shown to increase cardiac mortality in men with heart disease. As a result, men who have suffered from a previous heart attack, stroke or potentially fatal arrhythmia should talk to their physician before taking a PDE5 inhibitor.
Contraindications with Nitrates:
Along with warnings for cardiovascular-disease men, PDE5 inhibitors should not be administered to nitrate-treated men. This is because when these two classes of drugs are combined, blood pressure falls very low. The nitrates commonly prescribed for chest pain and angina include nitroglycerin, isosorbide dinitrate, and isosorbide mononitrate. Nitrate-treated men should inform their physician before receiving a PDE5 inhibitor.
Conclusion: PDE5 Inhibitors: Common ED Drugs And How They Work
PDE5 inhibitors are a safe and effective alternative to ED for men who desire better erectile function and life quality. These drugs act by raising cGMP levels and causing smooth muscle to relax in the corpus cavernosum. The three most frequently used PDE5 inhibitors are Sildenafil, Tadalafil, and Vardenafil – all of which have a different starting point and time-course. Although generally well tolerated, PDE5 inhibitors should be used sparingly in men with preexisting cardiovascular disease and not in combination with nitrates. As long as the field is well developed, PDE5 inhibitors will remain a fundamental part of ED management.
