From the side of the central nervous system: at the beginning of treatment - severe inhibition, fatigue, drowsiness, lethargy, dizziness, numbness, headaches; rarely - confusion, ataxia. When used in high doses, especially with prolonged treatment - violations of articulation, diplopia, nystagmus; paradoxical reactions (incl.acute excitation conditions); anterograde amnesia. Rarely - hyperergic reactions, muscle weakness - depression. With prolonged treatment of some forms of epilepsy, an increase in the frequency of seizures is possible.
From the digestive system: rarely dry mouth, nausea, diarrhea, heartburn, nausea, vomiting, decreased appetite, constipation or diarrhea, impaired liver function, increased activity of hepatic transaminases and alkaline phosphatase, jaundice. Infants and young children may have increased salivation.
From the cardiovascular system: reduction of blood pressure, tachycardia.
From the endocrine system: change in libido, dysmenorrhea, reversible premature sexual development in children (incomplete premature puberty).
From the respiratory system: with intravenous administration, respiratory depression may be possible, especially when treated with other drugs that cause respiratory depression; in infants and young children, bronchial hypersecretion is possible.
On the part of the hematopoiesis system: leukopenia, neutropenia, agranulocytosis, anemia, thrombocytopenia.
From the urinary system: urinary incontinence, urinary retention, renal dysfunction.
Allergic reactions: urticaria, skin rash, itching, extremely rarely - anaphylactic shock.
Dermatological reactions: transient alopecia, changes in pigmentation.
Influence on the fetus: teratogenicity (especially I trimester), oppression CNA, violation of respiration and suppression of the sucking reflex in newborns whose mothers used the drug.
Other: addictive, drug dependence (both physical and mental - the risk of dependence increases with increasing dose and duration of treatment, a predisposition is observed especially in patients with alcoholism or other kinds of dependencies in the anamnesis); a decrease in blood pressure; rarely - weight loss, tachycardia, transient alopecia, changes in pigmentation.
With a sharp decrease in dose or discontinuation of reception - the syndrome "canceling" (tremor, increased sweating, agitation, irritability, nervousness, sleep disturbances, expressed anxiety, dysphoria, spasm of smooth muscles of internal organs and skeletal muscles, myalgia, depression, nausea, vomiting, tachycardia, seizures and epileptic seizures, which may be a manifestation of the underlying disease; in severe cases, derealization, hyperacusis, paresthesia, photophobia, hyperesthesia, hallucinations can develop).Manifestations of the "withdrawal" syndrome are usually observed with a sharp cessation of treatment. Therefore, if it is necessary to stop treatment, the dose of the drug should be reduced gradually under the supervision of a doctor. With prolonged use, it is possible to develop drug dependence and weaken the effect of the drug as a result of the development of tolerance.