Bipolar disorder is characterized by a sequence of manic and depressive episodes. The quantity and intensity are extremely variable. In the manic phase, the main symptoms are expansive and irritable mood, hyperactivity, impulsivity, disinhibition. Also common symptoms are decreased need for sleep, accelerated thinking, psychotic symptoms and, in some selected patients, cognitive impairment. The depressive phase has characteristics similar to major depression. These are depressed mood, diurnal variation, sleep disturbance, anxiety and even psychotic symptoms.
In bipolar disorder, more often the patient opens the depressive state, and it may take time to open the manic condition. This fact makes diagnosis difficult, and many patients with bipolar disorder are mistakenly diagnosed with major depression during the first symptoms.
Lithium was the first agent proven to be useful in the treatment of the manic phase of bipolar disorder, which was also not an antipsychotic drug. However, mood-stabilizing drugs that also have anticonvulsant action (such as carbamazepine and valproic acid) have become more widely used than lithium.
Lamotrigine has been approved for use in preventing recurrence. Other drugs such as aripiprazole, chlorpromazine, olanzapine, quetiapine, risperidone and ziprasidone have been approved for the treatment of the manic phase of bipolar disorder.
Cynical Pharmacology
Lithium:
It has a slow onset of action, so it is often administered in combination with potent antipsychotics or benzodiazepines in patients with an episode of severe mania. Remission rate of patients in the manic phase can reach 80%. Although it is inferior in the case of hospitalized patients.
Lithium, in therapeutic concentrations, is devoid of autonomous blocking and activation or sedation effects, however, it can produce nausea and tremor. Unlike antipsychotic or antidepressant drugs, which are responsible for several actions on the central or autonomic nervous system.
The prophylactic use of lithium prevents both mania and depression and can also be used in patients with recurrent depression and in combination with conventional antidepressants in patients with major depression and poor response to monotherapy. It also has applicability in cases of schizoaffective disorder and schizophrenia (in association with antipsychotics in the case of patients resistant to treatment).
Measurements of serum lithium concentrations should be carried out to assess the dose required for the treatment of acute mania and also to assess the appropriate maintenance dose.
Side effects:
Neurological: tremors (which can be relieved with the administration of propranolol or atenolol), choreoathetosis, motor hyperactivity, ataxia, dysarthria and aphasia
Psychiatric: mental confusion and isolation
Thyroid : lithium probably decreases thyroid function in patients exposed to the drug (reversible and non-progressive effect)
Kidney: polydipsia, polyuria, nephrogenic diabetes insipidus, edema
Cardiac: sinus disease, which is a contraindication for the use of lithium
Others: transient acneiform rashes at the start of treatment, folliculitis, leukocytosis
Valproic acid
Indicated as an antiepileptic, valproic acid also has an anti-manic effect and has been used for this purpose. Valproic acid has an efficacy equivalent to that of lithium during the first weeks of treatment and has been effective in some patients who did not respond to lithium
Carbamazepine
Carbamazepine can be used for the treatment of acute mania, as well as for prophylactic therapy. Side effects tend to be less than those associated with lithium. Carbamazepine is at risk for blood dyscrasias when used as an anticonvulsant. However, such a risk was not observed when used as a mood stabilizer. Carbamazepine overdoses are an important emergency and, in general, should be treated efficiently
Other Drugs
Lamotrigine has not shown effectiveness in the treatment of acute mania, but it has been able to reduce the frequency of recurrent depressive cycles. With that, it was approved as a maintenance treatment for bipolar disorder.
