Imipramine is a tricyclic antidepressant. The active ingredient belongs to the dibenzazepine class.
What is imipramine?
Imipramine is a tricyclic antidepressant. Imipramine is an antidepressant that was among the first reliable drugs of this type. Thus, the drug served as a precursor for a variety of other agents for the treatment of depression. Imipramine was developed by the Swiss pharmaceutical company Geigy, now known as Novartis. The psychotropic drug, which belongs to the tricyclic antidepressants, came onto the market in 1958, but its discovery as an antidepressant came about only by chance. Thus, in 1957, the drug was originally intended to be administered by psychiatrist Roland Kuhn (1912-2005) for the treatment of schizophrenia. However, when the drug was tested in practice, imipramine was found to be unsuitable for this purpose. Instead, it was found to have a positive effect against depression, so imipramine could be used against this mental illness.
Pharmacologic effect
In the human brain, communication between nerve cells takes place with the help of so-called neurotransmitters, which are chemical messengers. In this process, neurotransmitters are secreted by a nerve cell. The neighboring nerve cell can recognize this via special docking sites called receptors and take up the messenger, which then returns to its cell of origin. Some messenger substances fulfill special tasks and have either an inhibitory or an excitatory effect. The messenger substance serotonin, for example, serves as a happiness hormone. It has not yet been possible to determine exactly what causes depression. One theory is that it is caused by a lack of specific messenger substances. Neurotransmitters such as serotonin, dopamine or norepinephrine are lacking. If these messenger substances are supplied to the patient through medication, this can bring about relief from depressive symptoms. Imipramine is one of these drugs. It has the property of increasing the concentration of messenger substances such as norepinephrine and serotonin in the body. In doing so, the substance ensures that the neurotransmitters are reabsorbed by the nerve cell. Imipramine also has a positive effect on other neurotransmitters. Imipramine is one of the antidepressants without drive, so the patient’s drive is neither increased nor weakened. Likewise, there is no sedative effect. In this respect, there is a difference from the desipramine-type antidepressants, which have a drive-increasing or sedative effect. After ingestion of imipramine, the active ingredient enters the blood via the intestine. Extensive breakdown of the substance takes place in the liver. The drug is excreted via the kidneys and urine. After only half a day, only 50 percent of the imipramine is still present in the body. During degradation, partial conversion to desipramine takes place, which has a drive-increasing effect.
Medical application and use
For use, imipramine is used for the treatment of depression. In addition, the drug is suitable for the treatment of pain caused by a psychological component. This may involve mild, moderate, or severe pain. Other indications for imipramine include anxiety at night (Pavor nocturnus) and bedwetting in children older than five years. Apart from the approved indications, the active ingredient is also administered for phobias or anxiety states. Effective treatment of depression with imipramine usually requires a longer period of time. In this context, the doctor must regularly check whether the use of the drug is still useful. Imipramine is taken with tablets independently of meals. The recommended initial dose is 25 milligrams of imipramine a day and is increased in the further course until it reaches the usual amount of 50 to 150 milligrams. Both doses are taken in the morning and in the evening. Toward the end of therapy, the dose should be gradually decreased.
Risks and side effects
Just as with the use of other antidepressants, undesirable side effects are also possible from taking imipramine. For example, one in ten patients suffers from a stuffy nose, dizziness, or tremors.Sweating, drowsiness, dry mouth, constipation, hot flashes, weight gain and palpitations. In addition, it is not uncommon to experience low blood pressure after getting up. Other side effects may include sleep problems, difficulty urinating, confusion, restlessness, fatigue, thirst, loss of appetite, nausea, vomiting, skin reactions, sensory dysfunction, or sexual dysfunction. Most side effects occur at the beginning of treatment with imipramine. However, once the body has become accustomed to the drug, the symptoms usually subside. Imipramine should not be used in cases of hypersensitivity to tricyclic and tetracyclic antidepressants. The same applies to the simultaneous administration of MAO inhibitors. Furthermore, imipramine is not allowed in cases of intoxication by psychotropic drugs, sleeping pills, painkillers or alcohol. In addition, the active substance must be avoided in cases of delirium, acute urinary retention, glaucoma, pyloric stenosis, intestinal obstruction or enlargement of the prostate with the formation of residual urine. Furthermore, interactions between imipramine and agents that have a depressant effect on the brain are within the realm of possibility. These may be sleeping pills or tranquilizers, which, like alcohol, further intensify the effect of imipramine. Special caution is also required when taking other antidepressants at the same time, which applies primarily to the serotonin reuptake inhibitors fluvoxamine and fluoxetine. It thereby increases the frequency of side effects.
