Tadalafil belongs to the group of phosphodiesterase-5 inhibitors (PDE-5 inhibitors), which is used for the following diseases: 1. erectile dysfunction 2. pulmonary arterial hypertension (PAH) 3. benign prostate syndrome.
Basically, PDE-5 inhibitors lead to vasodilatation of the vessels via intracellular signal cascades and a resulting increase in NO and cGMP.
1st Erectile Dysfunction: Besides sildenafil and other PDE-5 inhibitors, tadalafil is also available for the treatment of erectile dysfunction. Physiologically, PDE-5 ends an erection by breaking down cGMP. In the case of erectile dysfunction, the inhibition of PDE-5 can now prevent the breakdown of cGMP and vasodilation can be used to prolong an erection or even make it possible at all.
Pulmonary arterial hypertension: For the treatment of PAH, Tadalafil is used at a dosage of 40 mg/d, as it prolongs the effect of vasodilative endogenous NO and thus leads to a reduction in pulmonary resistance. As a result of this mode of action, the blood pressure in the pulmonary circulation decreases and symptoms such as dyspnoea (shortness of breath) and loss of performance decrease. It is important to note that there is no co-medication with riociguat.
3rd Benign Prostatic Syndrome: Since 2014, the prescription of Tadalafil 5 mg (Cialis®) has been approved for diagnostically confirmed benign prostatic syndrome. Due to the many contraindications, however, Tadalafil is still not the first choice for this indication.
The onset of action of Tadalafil occurs after about one hour, the half-life is about 17.5 h, so that an effect of up to 36 h can be achieved. Tadalafil is available in dosages of 5 to 20 mg, whereby the 5 mg dosage is suitable for daily use, so that a constant effect level can be maintained. However, this should be avoided at the higher dosages.
Side Effects:
The detailed side effects are not listed here. Common and very common side effects include headache, blurred vision, palpitations, reddening of the skin, rash, drop in blood pressure, swelling of the mucous membranes of the nose, nausea and vomiting, muscle and back pain. In occasional cases, taking it can lead to tachycardia and sudden cardiac death.
Contraindications:
Tadalafil should not be used in case of intolerance to the active substance and also not together with nitrates as it increases the risk of heart attack and may cause a sharp drop in blood pressure. Also contraindications are heart attacks within the last 90 days, strokes within the last 6 months, uncontrolled arrhythmias, hypotension, uncontrolled hypertension, unstable angina pectoris, heart failure NYHA >/= 2, concomitant therapy with guanylate cyclase stimulators (e.g. riociguat), other diseases that prohibit sexual activity and loss of vision after NAION.