Can Prozac make you more depressed?

Fluoxetine

This is how fluoxetine works

As an antidepressant, fluoxetine intervenes directly in the brain metabolism. In the brain, messenger substances, so-called neurotransmitters, transmit signals between the individual nerve cells: After being released from a nerve cell, the messenger substances dock at binding sites (receptors) in the neighboring cell and thus transmit a signal. To end the signal, the messenger substances are taken up again in the original cell.

The exact causes of depression are not yet known. We know, however, that at least one of the reasons for depressive illnesses can be a deficiency in the messenger substance serotonin (the "happiness hormone").

This is where fluoxetine comes in: It prevents the already released serotonin from being absorbed again into the cell - this allows the messenger substance to develop its mood-enhancing and anxiety-relieving effect on the target cells for longer. In addition, it was recently shown on certain receptors that fluoxetine can also bind directly to the target cell and mediate the same effect as serotonin.

The desired antidepressant effect of fluoxetine is achieved about one to two weeks after the start of therapy.

Fluoxetine uptake and breakdown

Fluoxetine is absorbed into the blood through the intestinal wall, where it reaches its maximum concentration about six hours after ingestion. Fluoxetine passes through the blood to the liver, where most of it is slowly metabolized, and to the brain, where it works. The blood level of the active ingredient falls by half after a single dose after about two days, after multiple doses after about four days - this so-called "half-life" is very long compared to other antidepressant active ingredients, which can have both advantages and disadvantages.

When is fluoxetine used?

The areas of application of fluoxetine generally include depressive disorders (episodes of major depressive disorder) as well as obsessive-compulsive disorder and especially bulimia ("binge eating"). In the latter case, psychotherapeutic advice must also be given. Usually this is also useful in other areas of application.

The doctor decides on a case-by-case basis how long fluoxetine must be used. However, it has been shown that drug therapy for depression with fluoxetine should last at least six months. For obsessive-compulsive disorder, shorter therapy periods are also common.

This is how fluoxetine is used

Fluoxetine is only offered for ingestion, usually as a tablet or hard capsule, occasionally also as a solution for drinking or tablets for preparing a drinking solution.

In most cases, it is recommended to take it once a day. In the case of high dosages or intolerance to the stomach, the daily dose can be divided and taken throughout the day. It can be taken with or between meals, as this does not affect the absorption of the active ingredient. The individual dose of fluoxetine required is determined by the doctor.

What are the side effects of fluoxetine?

Because the antidepressant has a particularly long duration of action and retention in the body, special attention must be paid to side effects during therapy. Because the fluoxetine effect can last for several days even after stopping the drug.

Fluoxetine often causes gastrointestinal disorders (nausea, vomiting, diarrhea), central nervous disorders (headache, dizziness, tremors, tiredness) and other symptoms (sweating, itching, hot flashes, chest pain). Male patients in particular should be made aware of the possible disruption of sexual function.

In every tenth to hundredth patient, fluoxetine can cause weight loss, increased blood pressure and visual disturbances. The heart rhythm can also change: The so-called QT interval in the ECG can lengthen, which is particularly important if the patient is taking other medication.

Psychological problems can also arise, especially at the beginning of fluoxetine therapy. These include, for example, fear, inner restlessness, thought disorders such as slowing down the thought processes or constant brooding, sleep problems and mood swings. Thoughts of suicide or even suicide attempts have also been reported. Therefore, doctors closely monitor patients for the first few weeks of treatment.

If rashes, shortness of breath and general symptoms of an allergic reaction occur, therapy should be stopped immediately and a doctor should be consulted, as life-threatening symptoms can occur, as with other allergies.

Because of the slow rate of excretion of the active ingredient, it can take a particularly long time for the adverse drug reactions (ADRs) to subside.

What should be considered when taking fluoxetine?

If other centrally acting drugs (i.e. those that work in the brain) are to be taken in addition to fluoxetine, this should be discussed with a doctor or pharmacist beforehand.

This applies in particular to other antidepressants (especially "MAO inhibitors") and preparations that have a direct effect on the serotonin system, such as tryptophan, tramadol and migraine drugs (triptans such as sumatriptan, some of which are also available without a prescription). In combination with fluoxetine, the so-called "serotonin syndrome" can occur, which requires immediate medical treatment.

When fluoxetine is broken down in the liver, enzymes are involved that also break down other active substances in the body. When used at the same time, there may be interactions. This applies, for example, to sleeping pills and sedatives from the group of benzodiazepines (such as diazepam), epilepsy drugs (antiepileptics such as phenytoin or carbamazepine), agents against cardiac arrhythmias (such as flecainide and encainide), agents against high blood pressure (such as metoprolol), chemotherapeutics ( like vinblastine) and other antidepressants or anti-psychotic agents.

In addition, alcohol should be avoided during therapy with fluoxetine because of the additional stress on the liver.

Taking anticoagulants at the same time can lead to increased anticoagulation and increase the risk of bleeding. The coagulation values ​​should therefore be closely monitored, especially at the beginning of therapy.

The active ingredient fluoxetine should not be used in children under 8 years of age. For older children and adolescents under 18 years of age, a specialist begins and monitors the therapy very closely. Fluoxetine has in fact led to an intensification of suicidal behaviors in adolescents and young adults, which in some cases actually resulted in suicide due to the drive-enhancing effect of fluoxetine. This undesirable effect applies to almost all SSRIs.

Fluoxetine should not be used by pregnant or breastfeeding women, as anomalies in the development of the child have been increasingly observed during treatment. If a woman becomes unplanned to become pregnant during treatment with fluoxetine, the antidepressant should be discontinued immediately and the doctor informed.

This is how you get drugs with the active ingredient fluoxetine

Due to the effect on the central nervous system and the numerous possible fluoxetine side effects, the antidepressant is only available with a prescription in the pharmacy.

How long has fluoxetine been known?

As early as 1972, fluoxetine was investigated by the pharmaceutical company Eli Lilly, and in 1977 it was submitted for approval in the USA. After more years of research and evaluation, fluoxetine was approved in the United States in 1987. The patent on the active ingredient fluoxetine expired in 2001, which allowed other manufacturers to bring fluoxetine to the market in the form of generics (copycat products) at lower prices.

More interesting facts about fluoxetine

The active substance Fluoxetine was one of the first so-called "blockbuster drugs" - drugs that generate annual sales of at least one billion US dollars for their manufacturer.

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