Prozac: the antidepressant par excellence

Prozac is a drug whose active ingredient is fluoxetine and is used as an antidepressant. It was a revolutionary drug in the treatment of depression, since it was the first to be prescribed by doctors not specialized in psychiatry.

It was launched on the market in 1988 by an American pharmaceutical company, Lilly. In Spain did not start selling until 1991. Our country was one of the first to incorporate this innovative drug.

The doctors trusted and trust a lot in their effectiveness and safety, since It is a drug that is tolerated very well and the side effects, which we will see later, are less than those of the molecules used previously.

Therefore, as Prozac had practically the same efficacy as existing drugs but with a more favorable safety profile, the primary care doctors began to prescribe it.

Interesting information about Prozac

As we already know, in Spain this drug was sold in 1991. Eight years later, that is, in 1999, generics began to be commercialized. On the other hand, Spain was the first country to launch the orodispersible format of Prozac.

This method of administration allows instant dissolution of the drug in the oral cavity. Before the patent expired in 1999, Prozac sales reached 37.7 million euros. When generics were introduced to the market, this figure decreased to 743,887 euros, data collected in November 2017.

As a curiosity, the fluoxetine capsule factories, which as we know is the active principle of Prozac, are found in Puerto Rico, Brazil and Turkey. As for the tablet and liquid factories, we find them in France. Finally, packaging in the US, China, Brazil, Saudi Arabia, Greece, Turkey and France.

This drug also revolutionized the field of research. The number of volunteers participating in a clinical trial for the development of new medicines increased significantly with the introduction of Prozac in the market.

How does Prozac work?

Fluoxetine is an antidepressant that belongs to the group of serotonin reuptake inhibitors.

Serotonin is a biogenic amine and acts as a neurotransmitter in our body. It is considered as the chemical responsible for keep the balance our mood.

In addition, serotonin is involved in smooth muscle contraction, nerve impulse transmission, regulation of the body's circadian processes and, contributes to well-being and happiness.

Therefore, Prozac binds selectively to the specific serotonin transporter. This receptor is located in the presynaptic membrane. When fluoxetine binds to this structure, inhibits the active reuptake of the neurotransmitter.

As a final result we get an increase in the concentration of serotonin in the presynaptic space, which is the one between one neuron and another. Having more serotonin in this space, more molecules of this neurotransmitter that can react with postsynaptic receptors and trigger their corresponding biological functions.

Pharmacokinetics of Prozac

The Prozac is administered orally and it is absorbed very well throughout the digestive tract. Keep in mind that the presence of food in the stomach can delay absorption but not the extension of it. The drug undergoes a hepatic first pass metabolism and maximum blood concentrations are observed at 6-8 hours.

One fact to keep in mind is that fluoxetine binds in a high percentage to plasma proteins. This feature can not be overlooked if you are administering some other drug that also binds to a high degree to proteins of the blood since they can interact between them and displace fluoxetine.

If this happens, the concentration of free drug in plasma will increase, and with it its effects, being able to produce a toxic picture. It is a drug that is metabolized by the liver by demethylation reactions. As a result of these biotransformations, metabolites are produced. The most important is norfluoxetine, which has the same effectiveness as the starting drug in the blockade of serotonin reuptake.

Approximately 60% of the dose is eliminated by urine, the rest by faeces. However, there are interindividual variations in the elimination of the drug.

Adverse reactions

Despite its effectiveness, Prozac has had many demands for its controversial side effects. Among them we can mention the sexual dysfunction or the retention of urine as the most serious. Keep in mind the fact that a drug is safe does not mean it has no adverse effects. Despite the two mentioned, the most frequent adverse effects of this drug are:

Although the effects mentioned above are frequent, they disappear, in many cases, by themselves throughout the treatment.