Side effects are mainly associated with the anticholinergic action of the drug: paresis of accommodation, blurred vision, increased intraocular pressure, dry mouth, constipation, intestinal obstruction, delayed urination, fever. All these phenomena usually pass after adaptation to the drug or reduce doses.
From the central nervous system: headache, ataxia, fatigue, weakness, irritability, dizziness, tinnitus, drowsiness or insomnia, impaired concentration, nightmares, dysarthria, confusion, hallucinations, motor excitement, disorientation, tremor, paresthesia, peripheral neuropathy, changes on the EEG. Rarely, extrapyramidal disorders, convulsions, anxiety.
From the side of the cardiovascular system: tachycardia, arrhythmia, violation conductivity, lability of arterial pressure, expansion of the complex QRS on ECG (violation of intraventricular conduction), symptoms of heart failure, fainting.
From the gastrointestinal tract: nausea, vomiting, heartburn, anorexia, stomatitis, taste disorders, darkening of the tongue, a feeling of discomfort in the epigastrium, gastralgia, increased activity of "liver" transaminases, rarely cholestatic jaundice, diarrhea.
From the endocrine system: increase in breast size in men and women, galactorrhea, changes in the secretion of antidiuretic hormone (ADH), changes in libido, potency. Rarely - hypo- or hyperglycemia, glucosuria, impaired glucose tolerance, edema of the testicles.
Allergic reactions: skin rash, itching, photosensitivity, angioedema, hives.
Other: agranulocytosis, leukopenia, eosinophilia, thrombocytopenia, purpura and other blood changes, hair loss, enlarged lymph nodes, weight gain with prolonged use, sweating, pollakiuria.
With long-term treatment, especially in high doses, with a sharp cessation of treatment, it is possible to develop a withdrawal syndrome: headache,nausea, vomiting, diarrhea, as well as irritability, sleep disturbance with bright, unusual dreams, increased excitability.