The undesirable reactions, the occurrence of which may or may not depend on the amount of the dose taken, are listed below, and in the latter case, be a consequence of the increased individual sensitivity of the patient.
Disorders from the central nervous system
- Sedation or drowsiness, more pronounced at the beginning of treatment and usually passing in a few days;
- Apathy, anxiety, mood changes;
- In some cases, paradoxical effects are possible: insomnia, agitation, sleep inversion, increased aggressiveness and increased psychotic symptoms;
- Extrapyramidal disorders (often occurring when using the drug in high doses):
- acute dystonia or dyskinesia (spasmodic torticollis, oculogic crises, trisus, etc.), usually occurring within 4 days after starting treatment or increasing the dose;
- Parkinsonism, which often develops in elderly patients and / or after long-term treatment (during weeks or months), is partially eliminated in the appointment of central m-holinoblockers and manifests itself with one or more of the following symptoms: tremor (very often the only manifestation of parkinsonism) , rigidity, akinesia in combination with or without muscle hypertension;
- late dystonia or dyskinesia, usually (but not always) arising from long-term treatment and / or use of the drug in high doses, and capable of arising even after cessation of treatment (central m-cholinoblockers do not cause any impairment if they occur);
- akathisia, usually observed after taking high initial doses.
Inhibition of respiration (possibly in patients with predisposing factors to the development of respiratory depression, for example, in patients receiving other drugs that can depress respiration, in senile patients, etc.).
Violation of the autonomic nervous system
Effects due to blockade of m-cholinergic receptors (dry mouth, paresis of accommodation, urinary retention, constipation, paralytic intestinal obstruction).
Violation of the cardiovascular system
- Decrease in blood pressure, usually postural arterial hypotension (more often occurs in elderly patients and patients with a decrease in the volume of circulating blood, especially at the beginning of treatment and when using high initial doses);
- Arrhythmias, including atrial rhythm disturbances, atrioventricular blockade, ventricular tachycardia, including potentially fatal ventricular "pirouette" tachycardia, more likely to occur with high doses (see "With caution," "Interaction with other drugs," "Special instructions ");
- ECG changes, usually minor: lengthening of the interval QT, segment depression ST, the appearance of a prong U and changes in the T wave;
- With the use of neuroleptics, there have been cases of venous thromboembolic complications, including pulmonary embolism (sometimes fatal) and cases of deep vein thrombosis (see "Special instructions").
Endocrine and metabolic disorders (often occurring when using the drug in high doses)
- Hyperprolactinemia, which can lead to amenorrhea, galactorrhea, gynecomastia, impotence, frigidity;
- Weight gain;
- Thermoregulation disorders;
- Hyperglycemia, a decrease in glucose tolerance.
Skin and allergic reactions
- Allergic skin reactions, skin rash;
- Bronchospasm, laryngeal edema, angioedema, hyperthermia and other allergic reactions;
- Photosensitivity (more often when using the drug in high doses);
- Skin sensitization (see "Special instructions").
Hematologic disorders
- Leukopenia (observed in 30% of patients receiving high doses of antipsychotics);
- Agranulocytosis, the development of which does not depend on the dose, and which can occur either immediately or after two to three months of leukopenia.
Ophthalmic disorders
Brownish deposits in the anterior chamber of the eye, pigmentation of the cornea and lens due to accumulation of the drug, usually not affecting the eyesight (especially when using high doses of drugs from the group of phenothiazine derivatives for a long time).
From the liver and biliary tract
Cholestatic jaundice and liver damage, mostly of cholestatic or mixed type, requiring discontinuation of the drug.
Other (General disorders)
- Malignant neuroleptic syndrome, potentially fatal syndrome, which can occur when all neuroleptics are taken and manifests itself as hyperthermia, muscle rigidity, vegetative disorders (pallor, tachycardia, unstable arterial pressure, increased sweating, shortness of breath) and impaired consciousness up to coma. The emergence of a malignant neuroleptic syndrome requires the immediate cessation of treatment with neuroleptics. Although this effect of pericyazin and other neuroleptics is associated with idiosyncrasy, there are predisposing factors for its occurrence, such as dehydration or organic lesions of the brain;
- Positive serological test for the presence of antinuclear antibodies, without clinical manifestations of lupus erythematosis;
- Very rarely: priapism;
- Nasal congestion;
- Very rarely: the development of withdrawal syndrome with a sharp discontinuation of treatment with high doses of pericyazine, manifested by nausea, vomiting,insomnia and the possibility of exacerbation of the underlying disease or development of extrapyramidal disorders;
- Single cases of sudden death, possibly caused by cardiac causes (see "Special instructions"), as well as unexplained cases of sudden death were noted in patients taking neuroleptics of the phenothiazine series.