What are PDE5 inhibitors?
Phosphodiesterase-5 inhibitors, PDE5 inhibitors for short, refer to drugs that are used in particular to treat erectile dysfunction. In addition, they have a blood pressure-lowering effect and are therefore used for high blood pressure in the lungs.
The best-known representative of this group of active ingredients is Sildenafil, which came onto the German market in 1998 under the brand name Viagra.
The effectiveness of PDE5 inhibitors in erectile dysfunction has been confirmed in numerous studies. The active ingredient tadalafil is also approved for the treatment of benign prostatic hyperplasia (BPH, benign enlargement of the prostate).
How do PDE5 inhibitors work?
The blood vessels of the penis are constricted in the non-erect state, so the erectile tissue contains little blood. During sexual arousal, a messenger substance called cyclic guanine monophosphate (cGMP) is released in the muscle cells. This causes the vascular muscles to relax and more blood to flow into the erectile tissue – the penis becomes stiff.
Erectile dysfunction is usually caused by not enough blood getting to the cavernous bodies of the penis. An erection is then, despite sexual arousal, difficult or even impossible. PDE5 inhibitors help by relaxing the vascular muscles and thus increasing blood flow.
PDE5 inhibitors work by blocking the enzyme phosphodiesterase-5. This is responsible for the breakdown of cGMP and thus influences erectile function. By taking PDE5 inhibitors, the concentration of the messenger substance increases, and a long-lasting erection occurs.
Since cGMP is only released when there is sexual stimulation, PDE5 inhibitors only show an effect when there is sexual arousal. The drugs have no positive effect on the patient’s sexual desire.
PDE5 inhibitors: what side effects can occur?
Like almost every drug, PDE5 inhibitors can also have side effects.
The most common include:
- Reddening of the skin (the so-called flush symptoms)
- Visual disturbances
- Stuffy nose
- Back and muscle pain
- Permanent erection
A detailed description and frequency of the respective side effects can be found in the information leaflet for the relevant medication.
Who shouldn’t take PDE5 inhibitors?
Patients who are already taking other medications to treat high blood pressure or heart disease should consult a doctor before taking a PDE5 inhibitor.
A combination with nitrate-containing medicines in particular can cause life-threatening circulatory crises.
Patients suffering from serious cardiovascular diseases such as heart failure, stroke, or cardiac arrhythmia should be particularly careful. Due to the increased physical exertion during sexual intercourse, there is a significant health risk.
The drugs are not approved for the treatment of women or minors.