Lithium has been known since the mid-20th century as a very effective psychotropic drug. It is mainly used as a so-called phase prophylactic in bipolar and schizoaffective disorders and in unipolar depression. Since the therapeutic window is very small, lithium therapy requires close monitoring of the blood count to avoid intoxication.

What is lithium?

Lithium is mainly used as a so-called phase prophylactic in bipolar and schizoaffective disorders as well as in unipolar depression.

Lithium is a chemical element belonging to the alkali metals. In the periodic table it is marked with the symbol "Li". In addition to industrial use, certain lithium salts have been used since the middle of the last century as phase prophylactics in psychiatric practice.

Phase prophylactics are psychotropic drugs designed to prevent rapid, pathological mood changes. Since its discovery, lithium has become a classic in the treatment of disturbed states of mind, such as bipolar psychosis (a change between mania and depression).

It is important to mention that lithium therapy is a preventative treatment. Although hereditary exposures to unipolar depression (non-manic depression), bipolar or schizoaffective psychosis (psychosis with affective and schizophrenic elements) are known in advance, lithium can not be given as a preventive measure to prevent first onset of the disease.

Pharmacological action

Although lithium has long been used as a phase prophylactic and tons of literature have been published about it, it is still unclear how it works in the body. Experts believe that it acts on the signal transmission between the synapses (the nerve endings in the brain, which are responsible for the transmission of stimuli).

One theory is that the flow of the messenger dopamine is throttled in the synaptic cleft. This should lead to a reduced excitability of the synapses.

Another theory assumes that lithium salts act on the noradrenaline and serotonin levels. Norepinephrine and serotonin are crucial messengers for the emotional state. While the amount of norepinephrine in a mania is high, depression can be attributed to a too low serotonin level.

Some researchers suggest that the sodium-potassium current is attenuated by lithium and thus the general excitability of the brain is lowered. Finally, there is evidence to suggest that the calcium concentration in the organism is lowered by lithium therapy. Especially in bipolar diseases but a high calcium concentration is detected.

There is also evidence to suggest that lithium salts affect GABA receptors in the brain, resulting in less excitability. GABA receptors are a natural device of the brain to maintain the balance between tension and relaxation.

Medical application & use

Lithium plays a significant role in psychiatric practice because it is a very effective mood stabilizer. Its discovery as a phase prophylactic is considered a milestone in the history of pharmacology. In the 1950s, it was discovered by chance that the administration of certain lithium salts had effects on the activity of rats based on animal experiments that originally had a completely different purpose. Since then, lithium has become established as a prophylactic agent in recurrent depression, mania, bipolar psychosis, and schizoaffective psychosis.

In unipolar depression, the chemical element is usually administered in conjunction with antidepressants. Manias can be contained in the acute stage by lithium, whereby the start-up time to the onset of action is about one week.

In bipolar psychoses, disease phases can often be suppressed or at least mitigated. Schizoaffective psychoses are pharmacologically treated with a combination of neuroleptics, antidepressants and lithium. In some cases, lithium is also used in therapy-resistant schizophrenia, where it is used in conjunction with neuroleptics.

According to numerous studies, lithium significantly reduces the risk of suicide in the mentally ill, with around one third of patients responding very well to the corresponding drugs, while at least a significant improvement can be seen in most others.

Prerequisite for the effectiveness of lithium is that the drug is taken regularly because it is a mirror drug. Finally, lithium is considered a second-line treatment for cluster headache (pain between the eyes, forehead, and temples).

Risks & Side Effects

Although the efficacy of lithium salts has been proven in psychiatric practice with still unclear mechanism of action, many unpleasant and even dangerous side effects can occur during therapy.

It should also be noted that the therapeutic and the toxic area are close together. At a concentration of more than one mmol / l there is a danger of poisoning, which can lead to coma. Ideally, the level in the blood is between 0.6 and 0.8 mmol / l and should therefore be checked every three months.

As lithium is excreted via the kidneys, a regular review of renal function is required. Patients with chronic or acute renal insufficiency should not be treated with lithium. Also prohibits a therapy for heart failure.

Common side effects include increased urinary frequency, increased appetite, diarrhea, vomiting, nausea and weight gain, especially the excess pounds affect the compliance of many patients, as they are perceived as very distressing.

At too high a dose, sluggishness, apathy, and indifference may also occur. In addition, in a lithium therapy to ensure adequate salt intake, since lithium salts flush out other salts from the organism. In the long term, the sodium level can sink dangerously low. All this requires accurate monitoring of drug administration. Self-medication can be life-threatening for lithium.

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