Introduction
Fenistil® drops are versatile drugs. Mostly they are used against allergies and skin reactions. These include allergic rhinitis or insect bites and hives.
They also have a sedative effect, making it easier to fall asleep. The active ingredient is dimetinden. This is a so-called antihistamine, i.e. an active ingredient that blocks the effect of histamine.
Indications
There are several reasons or indications for taking Fenistil® drops. Almost always certain symptoms should be relieved by taking them. Most of these symptoms are due to the effect of histamine.
Histamine is released in the body, for example, during allergic reactions. Among other things, it leads to itching or the typical reddening of the skin. The dimetinden contained in Fenistil® drops blocks this effect and thus provides relief from histamine-related itching, allergic rhinitis or insect bites.
Histamine plays a central role in all these diseases. Other areas of application for Fenistil® drops are hives or itching associated with wind pox in small children. Antihistamines, such as the dimetinden contained in Fenistil® drops, are usually the standard therapy for hives.
Chickenpox can be accompanied by very severe itching. Fenistil® drops can also be used here, as they relieve the itching. Almost all applications for Fenistil® drops are purely symptomatic treatments, since although the effect of histamine is blocked, the trigger for histamine release is not removed.
Urticaria
Hives is a skin reaction. It is similar to the painful swelling and wheals that occur after touching a nettle. The hives can have a variety of triggers.
These include allergic reactions to food or medicines, but also sunlight, heat, cold, pressure or psychological stress. Often no trigger can be identified. Fenistil® drops are well suited for the treatment of hives, as they can relieve the symptoms. However, this is a purely symptomatic therapy, the cause of the disease can usually not be eliminated.
Active ingredient
The active ingredient contained in Fenistil® drops is dimetinden. It blocks the H1-receptor. In an allergic reaction, histamine binds to this receptor.
By Dimetinden likewise to this receptor the H1-receptor binds, it weakens thus the effect of the Histamine. H1-receptors are found on the cell surfaces in different places and tissues in the body. Among other things, they mediate allergic skin reactions, but they also play a role in the brain in maintaining the day-night rhythm and the nausea stimulus.
Unlike newer antihistamines, Dimetinden can cross the blood–brain barrier. This means that it also affects the nervous system. Since histamine has a wake-up effect here via the H1 receptor, a blockage of the H1 receptor results in a slight sedation (fatigue-inducing effect).
A sleep-inducing effect is often reported. This is also one of the most important side effects of dimetinden. Histamine also plays a role in the central nervous system in triggering vomiting.
If H1-receptors are blocked here, vomiting can be prevented. This is also known as the antiemetic, i.e. vomiting preventing effect. Dimetinden not only binds H1 receptors but also a number of other receptors, which explains a number of other side effects.
