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What are PDE-5 Inhibitors?

To understand what PDE5 inhibitors are and their function, we must firstly understand the role of PDE (phosphodiesterase) in the body. A phosphodiesterase is any enzyme in the body that breaks a phosphodiester bond. In particular, cyclic nucleotide phosphodiesterases, which are the main group of enzymes that limit the bond in messenger molecules found between cAMP and cGMP. PDEs help in regulating the duration and strength of signalling between second messenger molecules.

When a man is sexually stimulated, molecular signals are sent to the brain, which causes the release of NO (nitric oxide) in the body. This in turn causes a dilation of the blood vessels found in the soft tissue of the penis (corpus cavernosum), as the NO converts GMP (guanosine monophosphate) to cGMP (cyclic guanosine monophosphate), resulting in arterial dilatation and venous contraction and leading to an erection. PDE5 is the predominant phosphodiesterase in the penile column as it serves to break down the cGMP, which causes the penis to return to a flaccid state after ejaculation. Erectile problems very likely occur when the PDE-5 has an increased level of activity, preventing the signals required for an erection to occur properly.

PDE5 inhibitors are therefore an effective line of treatment for men who struggle to get or maintain an erection due to the PDE-5 functions. These inhibitors prevent PDE5 enzymes from breaking down cGMP, which causes an increase in penile arterial dilation, allowing for an easier erection after arousal for a certain period of time.

Types of PDE-5 Inhibitors

PDE5 Inhibitors are available under various generic and branded names, and are usually the first call when treating erectile problems. Below is a table showing the main generic PDE5 inhibitors and their branded counterparts.

Generic Name Brand Names Dosage Onset Duration
Sildenafil Viagra 50-100mg 15-60mins 4 hours
Tadalafil Cialis,Cialis Daily 10-20mg 16-45mins 36 hours
Vardenafil Levitra 10-20mg 20-25mins 4 hours
Avanafil Spedra 50-200mg 30-45mins 6 hours

It is possible to use PDE-5 inhibitors if you are suffering from erectile problems due to emotional or psychological causes, high blood pressure, high cholesterol, diabetes, prostate surgery or even as a side effect of other medication. These treatments are also used by men with enlarged prostates or benign prostatic hyperplasia (BPH), as they help with the associated symptoms. The efficacy is usually based on the severity of the problem on the person, and the dosage taken also. Phosphodiesterase-5 inhibitors should usually be taken some time before sex and will only help in achieving an erection when sexual stimulation has occurred.

PDE5 Inhibitors - Side Effects

Although PDE5 inhibitors are an effective method of treating erectile problems (erectile dysfunction), men with certain conditions may be advised against using them. This includes men with very low blood pressure, uncontrolled angina, severe kidney or liver impairment or chronic cardiac failure. If looking to purchase any PDE-5 inhibitor treatment online, it is necessary to make sure the issuer is aware of any prior medical complications.

PDE5 inhibitors are only available as prescription treatments, and similar to other prescription treatments, there may be some side effects experienced during use. Many users don't experience side effects, and others are resolved as the body becomes accustomed to the treatment. Due to the varying nature of each PDE5 inhibitor, it may be best to understand what side effects are usually associated with these treatments. In this way you can select whichever is best suited to you. Below is a list of side effects that may be experienced during use:

  • Acid reflux, headaches, migraines, muscle aches and pains
  • Diarrhoea, blocked sinuses or a bloody nose, increased flushing

PDE5 inhibitors were the first and are the most effective medically prescribed forms of treatment for erectile problems. They are not complicated to use, and the various dosages and levels of efficacy means that it is not difficult to find a treatment that is suitable. Find out more information regarding erectile dysfunction and the range of available treatments here.

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