Fenistil drops
introduction
Fenistil® drops are medicinal products that can be used in many ways. Mostly they are used against allergies and skin reactions. This also includes allergic rhinitis or insect bites, as well as hives. They also have a sedating effect, making it easier to fall asleep. The active ingredient contained is dimetinden. This is a so-called antihistamine, i.e. an active ingredient that blocks the effects of histamine.
Indications
There are several reasons or indications for taking Fenistil® drops. Almost always, certain symptoms are supposed to be alleviated by ingestion. Most of these symptoms are due to the effects of histamine. For example, histamine is released in the body 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 of these diseases.
Other areas of application for Fenistil® drops are hives or chickenpox-associated itching in small children. For hives, antihistamines, such as the Dimetinden contained in Fenistil® drops, are usually the standard therapy. Chickenpox can be very itchy. Fenistil® drops can also be used here, as they relieve itching.
Almost all areas of application for Fenistil® drops are purely symptomatic, as although the effect of the histamine is blocked, the trigger for the histamine release is not eliminated.
Hives
Hives are a skin reaction. It is similar to the painful swellings and wheals that appear after touching a nettle. Hives can have a variety of triggers. These include allergic reactions to food or drugs, but also sunlight, heat, cold, pressure or psychological stress.
Often no trigger can be found. Fenistil® drops are good for treating hives as they can alleviate the symptoms. However, this is a purely symptomatic therapy; the cause of the disease can usually not be eliminated.
Active ingredient
The active ingredient in Fenistil® drops is dimetindene. It blocks the H1 receptor. In the event of an allergic reaction, histamine binds to this receptor. As Dimetinden also binds to this receptor, the H1 receptor, it weakens 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 also play a role in the brain in maintaining the day-night rhythm and nausea.
Unlike newer antihistamines, Dimetinden can cross the blood-brain barrier. As a result, it also affects the nervous system. Since histamine has a waking effect via the H1 receptor, a blockage of the H1 receptor leads to slight sedation (drowsy effect). A sleep-promoting effect is often reported. This is also one of the major side effects of dimetinden.
Histamine also plays a role in triggering vomiting in the central nervous system. If the H1 receptors are blocked here, vomiting can be prevented. One also speaks of the antiemetic, i.e. vomiting-preventing effect.
Dimetinden not only binds H1 receptors, but also a number of other receptors, which explains various other side effects.
effect
The active ingredient dimetinden contained in Fenistil® drops weakens the effect of histamine in the body. Histamine plays an important role in many processes in the body, for example in defense reactions against foreign substances.
It dilates blood vessels and increases the permeability of the vessel wall. This makes the irritated area of the skin appear red and overheated, causing swelling. The affected area also becomes itchy or painful. This is a useful defense reaction in the event of an insect bite, for example.
In the case of an allergy, however, there is a hypersensitivity to actually harmless substances. Histamine also plays an important role here. Even with an allergy, histamine can cause the typical swelling, overheating and redness.
The swelling of the nose and throat is also caused by histamine, among other things. By weakening the effect of the histamine, Fenistil® drops relieve the symptoms of an allergy. They also help with insect bites or hives.
side effect
Like any drug, Fenistil® drops are not free from side effects. As already described, fatigue occurs very often. This effect is based on the above-described effect as an "antihistamine".
Conversely, after taking Fenistil® drops, nervousness or excitement can rarely occur. Patients complain of headaches or dizziness even more rarely.
The active ingredient Dimetinden contained in Fenistil® drops not only binds to histamine receptors. So-called muscarinic acetylcholine receptors are also blocked by Dimetinden. These receptors are widespread in the body and control gastrointestinal activity or the flow of saliva, for example. That is why Fenistil® drops can in rare cases lead to dry mouth or gastrointestinal complaints. These rare side effects affect one to ten people in 10,000.
Even if Dimetinden is actually used against allergies, the body can become sensitized to the active ingredient. In this case, the person being treated becomes allergic to the active substance and a potentially dangerous anaphylactic shock occurs after ingestion. However, this probably only happens in exceptional cases.
Regarding babies
Small children and babies are often more affected by side effects than adults. There are several reasons for this. On the one hand, the mass of a baby is usually lower, so that the active ingredient can take a higher concentration.
In addition, the composition of an adult body differs from that of a baby. Since active ingredients accumulate or distribute themselves to different degrees in adipose tissue, for example, this can influence the effect on a baby.
In addition, the blood-brain barrier in babies is probably not fully developed. Therefore, drugs that cannot work in the central nervous system in adults can cross the protective blood-brain barrier in babies and thus have undesirable effects.
When taking Fenistil® drops, a strong sedative (calming) effect is often reported in young children, as the dimetinden it contains has a drowsy effect in the central nervous system. It is generally not recommended to take Fenistil® drops for children under one year of age.
Side effects in babies and young children
The side effects mentioned can of course also occur in babies or toddlers after administration. Children may experience more severe side effects due to their lower mass and other differences from adults. Children under one year of age should not take Fenistil® drops or only take them in an emergency and then after consulting a pediatrician. The mother should also avoid Fenistil® drops while breastfeeding. A sufficient dose reduction should be ensured in children over one year of age.
Arousal states have also been observed in children after taking antihistamines such as Fenistil® drops.
Interactions
With certain drugs, if taken at the same time as Fenistil® drops, there may be interactions. This shows up in undesirable effects or a change in the effectiveness of the substances taken. In general, the intake of several medications and Fenistil® drops should always be discussed with a doctor.
Particular care should be taken when taking a tricyclic antidepressant and Fenistil® drops at the same time. Both are characterized by a so-called anticholinergic effect, which can lead to a glaucoma attack in endangered patients, which if left untreated can lead to blindness.
Other drugs that warn of drug interactions include drugs used for epilepsy, certain sleep aids, anti-anxiety drugs, and other antihistamines. The cytostatic procarbazine or strong pain relievers, so-called opioid analgesics, can also interact with Fenistil® drops.
The same applies to medicines for stomach or abdominal cramps, these also have an anticholinergic effect. Further interactions can occur when Fenistil® drops are taken at the same time as medicines against vomiting or nausea, so-called antiemetics.
Due to the large number of possible interactions, the intake of Fenistil® drops should always be discussed with a doctor or pharmacist. There are also several databases on the Internet for interactions, which can be viewed freely.
dosage
If Fenistil® drops are prescribed by a doctor, he will usually explain the appropriate dosage. Adults usually receive three doses of Fenistil® drops per day. This is 20-40 drops of the solution three times a day.
There is no need to adjust this dose for people over 65. Children between one and eight years of age should also take Fenistil® drops three times a day, but in a reduced dose. This means that 10-15 drops are sufficient per intake. Children over nine years of age receive 20 drops per dose, also three times a day.
If you forget to take a dose, you should not take double the amount, but continue with the plan unchanged. Due to the sedative (= drowsy) effect, the intake plan must be changed slightly in people who tend to be sleepy.
Therefore, in this case it can be worthwhile to take Fenistil® drops only in the morning and in the evening. Unless otherwise instructed, 20 drops are taken in the morning and 40 drops in the evening.
For more information, please see the package insert.
Do Fenistil drops require a prescription?
Fenistil® drops can be sold without a prescription in Germany. When taken correctly, they are relatively harmless. Even if Fenistil® drops do not require a prescription, they are still medicinal products.
This means that the intake needs to be carefully considered and can also be associated with undesirable effects. In the event of an overdose, a doctor should be consulted. The use of Fenistil® drops should also be discussed with a doctor in case of doubt, especially if other medications are already being taken.
price
Fenistil® drops are a relatively cheap drug.
Since Fenistil® drops are not only taken for acute relief of symptoms, but also over a longer period of time, higher costs can still arise over time, which is why it is advisable to have them covered by the health insurance company.
