From the nervous system: headache, dizziness, asthenia, drowsiness or insomnia, fear, anxiety, psychomotor agitation, aggressiveness, paresthesia, small tremor, hypertonic muscle, speech disturbance, ataxia, hallucinations, confusion, disorientation, depersonalization,decrease in concentration of attention, delirium, in patients in the depressive phase may develop manic disorders, "nightmarish" dreams, less often: convulsive seizures, myoclonia, extrapyramidal disorders, agitation.
From the sense organs: paresis of accommodation, blurred vision (veil before the eyes), taste change, tinnitus.
From the digestive system: dry mouth, anorexia, nausea, vomiting, diarrhea, changes in functional hepatic tests, hepatitis, jaundice, constipation, increased appetite.
From the side of the cardiovascular system: orthostatic hypotension, sinus tachycardia, changes on the ECG, very rarely - violation of intracardiac conduction, incl. expansion of the QRS complex, prolongation of the Q-T interval, change in the P-Q interval, bundle branch blockade, ventricular tachycardia (such as "torsades de points"), especially against hypokalemia. increase in blood pressure.
On the part of the organs of hematopoiesis: very rarely - leukopenia, agranulocytosis, eosinophilia, thrombocytopenia, purpura.
From the endocrine system: very often - weight gain, violation of libido and potency; dysmenorrhea, often - galactorrhea, enlarged mammary glands; very rarely - the syndrome of inadequate secretion of ADH.
From the urinary system: retention of urine.
Allergic reactions: itching, photosensitivity, "tides" of blood to the skin of the face, a feeling of heat or cold, hyperpyrexia.
Other: petechiae, alopecia, increased incidence of dental caries.
With prolonged treatment, especially in high doses, with a sudden cessation of treatment, the development of withdrawal syndrome is possible: headache, abdominal pain, nausea, vomiting, diarrhea, as well as irritability, sleep disturbance with bright, unusual dreams, increased excitability.