Dosage

In general, lithium should be taken in the evening. For this reason, side effects are usually simply overslept. The amount that the individual patient has to take depends directly on the so-called plasma concentration, i.e. the amount of the drug in the blood.

Particularly at the beginning of the therapy, regular blood samples must be taken so that one does not accidentally “overshoot the mark. “Ideally, lithium therapy should be started under stationary conditions, i.e. in a hospital. Lithium is available in Germany in dosages from 150mg (leukominerase) to 536mg (Quilonum). As a rule, the plasma level must not exceed a concentration of 1.2 mmol/l, otherwise serious side effects may occur. (see below)

Side effects

The side effects of lithium therapy are rare and also easy to control. Only in very isolated cases do massive symptoms of poisoning occur. If the patient is well adjusted and observed during the therapy, signs of side effects can usually be detected early.

The patient should also observe himself/herself and if irregularities are noticed, consult the treating physician. This gives the patient the opportunity to react in time and, if necessary, to adjust the dose or take other measures. In this context it is also important to pay attention to possible interactions with other drugs.

The side effects usually depend on the dose, so that a dose reduction can be helpful if symptoms occur. This should be decided by the doctor together with the patient. Side effects are observed in everyday clinical practice mainly at the beginning of lithium therapy, less so in long-term treatment.

The most frequently complained NW are Especially in the first two years of treatment, weight gain can often occur, which also depends on the dose.

Trembling (fine tremor)
Memory and concentration disorders
Weight increase
Frequent urination
Nausea, diarrhea
Vomiting
Thirst
Urge to urinate / increased urination (polyuria)

The thyroid gland and the kidney also play a special role in lithium treatment. For the above-mentioned reasons, it is therefore essential to take a close look at a patient’s thyroid and kidneys with the help of laboratory tests before starting therapy.

Lithium can cause an increase in TSH in the thyroid gland and enlargement of a goiter (enlargement of tissue). In other rare cases it can lead to hypothyroidism and parathyroid hyperthyroidism.
In the kidneys, lithium can lead to kidney dysfunction, which usually disappears on its own after the drug is discontinued. In very rare cases it can also lead to an inflammatory complication (glomerulonephritis).

In the area of nerve and muscle function, the following symptoms may occur in rare cases when taking lithium.

Cognitive limitations such as memory disorders, drowsiness, clouding of consciousness and psychiatric phenomena such as hallucinations and anorexia can also occur. Lithium therapy may also have side effects such as slurred speech and dizziness. Another side effect that can be unsettling for the patient is the so-called pseudotumor cerebri, which causes increased pressure in the skull, whereby a tumor can be excluded as a possible cause.

Symptoms are severe headache with a feeling of pressure, which increases when lying down, coughing or sneezing. This side effect can be treated with a potent diuretic or a regular nerve fluid withdrawal, which serves to reduce the pressure in the brain.

Muscular weakness
Muscle trembling and twitching
Movement disorders
Reduced nerve conduction velocity
Disturbances of the reflexes
Nystagmus
Visual field failures

On the vegetative level, the following undesirable effects may occur: Not only at the beginning of the lithium therapy, but also in the further course, digestive disorders such as diarrhoea, nausea and vomiting can occur.Patients consider the rare sexual side effects such as loss of libido, reduced potency and even impotence to be potentially distressing.

Taste disorders
Increased saliva production or even dry mouth
Low blood pressure (hypotension)

The long-term use of lithium for the prophylaxis of bipolar affective disorders (a mixture of manias and depression) is often accompanied by continuous weight gain. The lower the lithium dosage used for therapy, the less pronounced the weight gain. The causes have not yet been fully clarified – the influence of lithium on appetite-regulating centers in the brain is being discussed.

However, the weight gain is very slow. According to experience, it amounts to about 1 kilogram per year, but can vary considerably from patient to patient. Patients who were already overweight before the start of therapy are particularly affected.

However, since prophylactic treatment with lithium can take several years or even decades, significant weight gains are possible overall. Individual patients have gained between 30 and 40 kilograms. For this reason, regular weight checks should be carried out during therapy and the weight should be monitored by the treating physician.

Changes in the blood count can also occur, which can lead to an increase in the number of leukocytes in the blood and a decrease in the pH value. Possible elevated blood sugar levels are of particular concern to diabetics. Furthermore, electrolyte shifts in the form of hypercalcemia and lowered potassium and sodium levels may occur.

The latter are the result of a misregulated water balance. In the course of such a disorder, oedema and the above-mentioned polyuria can also occur. Damage to the kidney can sometimes be observed during long-term therapy, which further aggravates the problem of fluid regulation.

Side effects similar to rheumatoid symptoms can also occur, such as joint pain, muscle pain and the flare-up of psoriasis vulgaris. Other inflammatory processes can also develop due to the intake of lithium. This can lead to gastritis, skin rashes, swelling of the oral mucosa, acne-like symptoms, itching and oedema.

During the course of lithium therapy, symptoms affecting the heart may also occur. These include cardiac arrhythmia, which in this case is usually accompanied by a slowing of the heart rate. In addition, changes may be noticed when measuring an ECG. Especially initially, hypotension, i.e. too low blood pressure, may occur.