Generally, adverse reactions occur at a low frequency; the most common reported adverse reactions are nervous system disorders.
Adverse effects: Immune system disorders:
Type I hypersensitivity reactions such as angioedema and urticarial.
Blood and lymphatic system disorders:
A mild leukopenia occurs in up to 30% of patients on prolonged high dosage.
Agranulocytosis may occur rarely: it is not dose related.
Hyperprolactinaemia which may result in galactorrhoea, gynaecomastia, amenorrhoea; impotence.
Nervous system disorders:
Acute dystonia or dyskinesias, usually transitory are commoner in children and young adults, and usually occur within the first 4 days of treatment or after dosage increases.
Akathisia characteristically occurs after large initial doses.
Parkinsonism is more common in adults and the elderly. It usually develops after weeks or months of treatment. One or more of the following may be seen: tremor, rigidity, akinesia or other features of Parkinsonism. Commonly just tremor.
Tardive dyskinesia: If this occurs it is usually, but not necessarily, after prolonged or high dosage. It can even occur after treatment has been stopped. Dosage should therefore be kept low whenever possible.
Insomnia and agitation may occur.
Ocular changes and the development of metallic greyish-mauve coloration of exposed skin have been noted in some individuals mainly females, who have received chlorpromazine continuously for long periods (four to eight years). This could possibly happen with prochlorperazine.
ECG changes include QT prolongation (as with other neuroleptics), ST depression, U-Wave and T-Wave changes.
Cardiac arrhythmias, including ventricular arrhythmias and atrial arrhythmias, a-v block, ventricular tachycardia, which may result in ventricular fibrillation or cardiac arrest have been reported during neuroleptic phenothiazine therapy, possibly related to dosage. Pre-existing cardiac disease, old age, hypokalaemia and concurrent tricyclic antidepressants may predispose.
There have been isolated reports of sudden death, with possible causes of cardiac origin, as well as cases of unexplained sudden death, in patients receiving neuroleptic phenothiazines.
Hypotension, usually postural, commonly occurs. Elderly or volume depleted subjects are particularly susceptible; it is more likely to occur after intramuscular injection.
Cases of venous thromboembolism, including cases of pulmonary embolism and cases of deep vein thrombosis have been reported with antipsychotic drugs - Frequency unknown.
Dry mouth may occur.
Metabolism and nutrition disorders:
Syndrome of inappropriate antidiuretic hormone secretion (SIADH).
Respiratory, thoracic and mediastinal disorders:
Respiratory depression is possible in susceptible patients.
Nasal stuffiness may occur.
Jaundice, usually transient, occurs in a very small percentage of patients taking neuroleptics. A premonitory sign may be sudden onset of fever after one to three weeks of treatment followed by the development of jaundice. Neuroleptic jaundice has the biochemical and other characteristics of obstructive jaundice and is associated with obstruction of the canaliculi by bile thrombi; the frequent presence of an accompanying eosinophilia indicates the allergic nature of this phenomenon. Treatment should be withheld on the development of jaundice.
Skin and subcutaneous tissue disorders:
Contact skin sensitisation may occur rarely in those frequently handling preparations of certain phenothiazines.
Skin rashes of various kinds may also be seen in patients treated with the drug.
Patients on high dosage should be warned that they may develop photosensitivity in sunny weather and should avoid exposure to direct sunlight.
General disorders and administration site conditions:
Neuroleptic malignant syndrome (hyperthermia, rigidity, autonomic dysfunction and altered consciousness) may occur with any neuroleptic.
Intolerance to glucose, hyperglycaemia.
Pregnancy, puerperium and perinatal conditions: Drug withdrawal syndrome neonatal - Frequency not known.
Adverse Drug Reaction:
Inform doctors about unexpected reactions after using drugs.