Fluoxetine is a drug in the antidepressant drug class. The active ingredient belongs to the selective serotonin reuptake inhibitors (SSRIs).
What is fluoxetine?
Fluoxetine is used in Germany to treat depression. Fluoxetine is the second drug in the selective serotonin reuptake inhibitor (SSRI) generation, after zimelidine (now no longer approved). The first patent was granted to the pharmaceutical company Lilly in 1975. It was launched on the U.S. market under the name Prozac in 1988. In Germany, the drug has been available since 1990 as Fluctin. Selective serotonin reuptake inhibitors such as Fluoxetine are used in Germany to treat depression. The drug is also used in the treatment of obsessive-compulsive disorders or bulimia. One of the most common side effects of the antidepressant is nausea. One fifth of all patients treated with fluoxetine complain of severe nausea. Furthermore, insomnia and severe fatigue may occur.
Pharmacologic effects
Fluoxetine inhibits the reuptake of serotonin in the synaptic cleft. Serotonin is a neurotransmitter and a tissue hormone. The substance is found in the intestinal nervous system, central nervous system, blood, and cardiovascular system. In these organ systems, serotonin fulfills various functions. For example, it ensures the relaxation of the smooth muscles in the blood vessels or stimulates intestinal activity. However, serotonin has its best-known effect on mood. Serotonin conveys a feeling of serenity, contentment and inner peace. A lack of serotonin leads to feelings of anxiety, depression, grief and aggressiveness. Because of this effect, serotonin is also popularly called the happiness hormone. Depressive and other mentally ill patients often show a pronounced deficiency of serotonin. This is why selective serotonin reuptake inhibitors such as fluoxetine are used. Fluoxetine inhibits the uptake of serotonin from the synaptic cleft. This prolongs the effect of the neurotransmitter that has already been taken up. Furthermore, fluoxetine shows a direct effect on serotonin receptors in the central nervous system. At higher doses, fluoxetine may also inhibit the reuptake of norepinephrine.
Medicinal application and use
The drug fluoxetine is used to treat obsessive-compulsive disorder and depression. The drug is also used as an adjunct medication in the treatment of eating disorders and self-induced vomiting. By increasing serotonin levels in the brain, fluoxetine provides an increase in drive for those affected.
Risks and side effects
The drug fluoxetine should not be used in children under eight years of age. In children older than eight years and in adolescents, it may be used to treat major depression. It should be noted that fluoxetine can lead to suicidal behavior, especially in younger people. This results from the fact that some depressed patients, due to the gained energy of the antidepressants, now put suicidal thoughts, initially only imagined, into action. Previously, they lacked the energy to do so. Fluoxetine should not be used in acute manic states. Patients with mania suffer from an abnormally elevated mood, which would increase further if fluoxetine were taken. Furthermore, the drug must not be taken together with MAO inhibitors. MAO inhibitors are used to treat depression and Parkinson’s disease. In combination with fluoxetine, severe to fatal side effects may occur. After stopping fluoxetine, patients must wait at least five weeks before they are allowed to take an MAO inhibitor. Therefore, switching from fluoxetine to an MAO inhibitor or from an MAO inhibitor to fluoxetine must be done only under the supervision of a physician. Nausea is one of the most common side effects of the drug. More than 20 percent of all patients taking fluoxetine experience nausea. Insomnia is also among the common side effects. Other side effects include fatigue and loss of appetite. Anxiety, nervousness, muscle weakness, and muscle tremors are also potential side effects. In particular, anxiety, mania, nervousness, and sleep disturbances cause patients to discontinue treatment with fluoxetine. Another common side effect of Selective Serotonin Reuptake Inhibitors such as fluoxetine is libido disturbance.Other sexual dysfunctions, such as the inability to experience orgasm, can also be side effects of SSRIs. Some patients develop hives and sometimes severe skin rashes while taking the antidepressant. About one-third of patients with these skin symptoms discontinue fluoxetine therapy. The phenomenon of akathisia (sitting restlessness) also occurs frequently as a side effect. In akathisia, patients cannot remain still in one position. They are very restless. Akathisia usually occurs immediately after starting therapy or when the dose is increased. It disappears when treatment is stopped or the dose is reduced. When fluoxetine is combined with drugs that also affect the serotonin system, the so-called serotonin syndrome may develop. This is a complex of symptoms caused by the accumulation of serotonin in parts of the body. Symptoms of serotonin syndrome include sweating, tremors, and chills. The syndrome can be fatal in some cases. Special caution should be exercised when combining fluoxetine with MAO inhibitors, tramadol, triptans, lithium, St. John’s wort, and tryptophan. Blood level shifts and toxicities may develop when fluoxetine is combined with agents such as carbamazepine, haloperidol, or tricyclic antidepressants.
