STEMETIL tablets Special Precautions
STEMETIL tablets Special Precautions
Stemetil should be avoided in patients with liver or renal dysfunction, Parkinson's disease, hypothyroidism, cardiac failure, phaeochromocytoma, myasthenia gravis, prostate hypertrophy. It should be avoided in patients known to be hypersensitive to phenothiazines or with a history of narrow angle glaucoma or agranulocytosis.
Close monitoring is required in patients with epilepsy or a history of seizures, as phenothiazines may lower the seizure threshold.
As agranulocytosis has been reported, regular monitoring of the complete blood count is recommended. The occurrence of unexplained infections or fever may be evidence of blood dyscrasia, and requires immediate haematological investigation.
It is imperative that treatment be discontinued in the event of unexplained fever, as this may be a sign of neuroleptic malignant syndrome (pallor, hyperthermia, autonomic dysfunction, altered consciousness, muscle rigidity). Signs of autonomic dysfunction, such as sweating and arterial instability, may precede the onset of hyperthermia and serve as early warning signs. Although neuroleptic malignant syndrome may be idiosyncratic in origin, dehydration and organic brain disease are predisposing factors.
Acute withdrawal symptoms, including nausea, vomiting and insomnia, have very rarely been reported following the abrupt cessation of high doses of neuroleptics. Relapse may also occur, and the emergence of extrapyramidal reactions has been reported. Therefore, gradual withdrawal is advisable.
In schizophrenia, the response to neuroleptic treatment may be delayed. If treatment is withdrawn, the recurrence of symptoms may not become apparent for some time.
Neuroleptic phenothiazines may potentiate QT interval prolongation which increases the risk of onset of serious ventricular arrhythmias of the torsade de pointes type, which is potentially fatal (sudden death). QT prolongation is exacerbated, in particular, in the presence of bradycardia, hypokalaemia, and congenital or acquired (i.e. drug induced) QT prolongation. The risk-benefit should be fully assessed before Stemetil treatment is commenced. If the clinical situation permits, medical and laboratory evaluations (e.g. biochemical status and ECG) should be performed to rule out possible risk factors (e.g. cardiac disease; family history of QT prolongation; metabolic abnormalities such as hypokalaemia, hypocalcaemia or hypomagnesaemia; starvation; alcohol abuse; concomitant therapy with other drugs known to prolong the QT interval) before initiating treatment with Stemetil and during the initial phase of treatment, or as deemed necessary during the treatment.
Avoid concomitant treatment with other neuroleptics.
Stroke: In randomised clinical trials versus placebo performed in a population of elderly patients with dementia and treated with certain atypical antipsychotic drugs, a 3-fold increase of the risk of cerebrovascular events has been observed. The mechanism of such risk increase is not known. An increase in the risk with other antipsychotic drugs or other populations of patients cannot be excluded. Stemetil should be used with caution in patients with stroke risk factors.
As with all antipsychotic drugs, Stemetil should not be used alone where depression is predominant. However, it may be combined with antidepressant therapy to treat those conditions in which depression and psychosis coexist.
Because of the risk of photosensitisation, patients should be advised to avoid exposure to direct sunlight.
To prevent skin sensitisation in those frequently handling preparations of phenothiazines, the greatest care must be taken to avoid contact of the drug with the skin.
It should be used with caution in the elderly, particularly during very hot or very cold weather (risk of hyper-, hypothermia).
The elderly are particularly susceptible to postural hypotension.
Stemetil should be used cautiously in the elderly owing to their susceptibility to drugs acting on the central nervous system and a lower initial dosage is recommended. There is an increased risk of drug-induced Parkinsonism in the elderly particularly after prolonged use. Care should also be taken not to confuse the adverse effects of Stemetil, e.g. orthostatic hypotension, with the effects due to the underlying disorder.
Children: Stemetil has been associated with dystonic reactions particularly after a cumulative dosage of 0.5 mg/kg. It should therefore be used cautiously in children.
STEMETIL tablets Adverse Reactions
STEMETIL tablets Adverse Reactions
Generally, adverse reactions occur at a low frequency; the most common reported adverse reactions are nervous system disorders.
Adverse effects:
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.
Endocrine: 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.
Eye disorders: 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 Stemetil.
Cardiac disorders: 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.
Vascular disorders: Hypotension, usually postural, commonly occurs. Elderly or volume depleted subjects are particularly susceptible; it is more likely to occur after intramuscular injection.
Gastrointestinal disorders: dry mouth may occur.
Respiratory, thoracic and mediastinal disorders: Respiratory depression is possible in susceptible patients. Nasal stuffiness may occur.
Hepato-biliary disorders: 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 eosinphilia 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
STEMETIL tablets Contraindications
STEMETIL tablets Contraindications
Known hypersensitivity to prochlorperazine or to any of the other ingredients.