- cyclizine hydrochloride
This information is intended for use by health professionals
|Valoid is indicated for the prevention and treatment of nausea and vomiting including:-|
|• Motion sickness.• Nausea and vomiting caused by narcotic analgesics and by general anaesthetics in the post-operative period.• Vomiting associated with radiotherapy, especially for breast cancer since cyclizine does not elevate prolactin levels.|
|Valoid may be of value in relieving vomiting and attacks of vertigo associated with Meniere's disease and other forms of vestibular disturbance.|
Adults and Children over 12 Years:50 mg orally, which may be repeated up to three times a day.
Children 6 12 Years:25 mg orally, which may be repeated up to three times a day.
Children less than 6 years of age:Valoid tablets are not recommended for children less than 6 years of age.
Use in the Elderly:There have been no specific studies of Valoid in the elderly. Experience has indicated that normal adult dosage is appropriate.To prevent motion sickness Valoid should be taken about one to two hours before departure.
Blood and lymphatic system disordersAgranulocytosis
Eye disordersBlurred vision, oculogyric crisis
Gastrointestinal system disordersDryness of the mouth, nose and throat, constipation
General disorders and administration site conditionsAsthenia
Hepatobiliary disordersHepatic dysfunction, hypersensitivity hepatitis, cholestatic jaundice and cholestatic hepatitis have occurred in association with cyclizine.
Immune system disordersHypersensitivity reactions, including anaphylaxis have occurred
Musculoskeletal and connective tissue disordersTwitching, muscle spasms
Nervous system disordersEffects on the central nervous system have been reported with cyclizine these include somnolence, headache, dystonia, dyskinesia, extrapyramidal motor disturbances, tremor, convulsions, dizziness, decreased consciousness, transient speech disorders, paraesthesia and generalised chorea.
Psychiatric disordersDisorientation, restlessness, nervousness, insomnia and auditory and visual hallucinations have been reported, particularly when dosage recommendations have been exceeded.
Renal and urinary disordersUrinary retention
Respiratory, thoracic and mediastinal disordersBronchospasm, apnoea
Skin and subcutaneous tissue disordersUrticaria, drug rash, angioedema, allergic skin reactions, fixed drug eruption
Symptoms:Symptoms of acute toxicity from cyclizine arise from peripheral anticholinergic effects and effects on the central nervous system.Peripheral anticholinergic symptoms include dry mouth, nose and throat, blurred vision, tachycardia and urinary retention. Central nervous system effects include drowsiness, dizziness, incoordination, ataxia, weakness, hyperexcitability, disorientation, impaired judgement, hallucinations, hyperkinesia, extrapyramidal motor disturbances, convulsions, hyperpyrexia and respiratory depression.An oral dose of 5 mg/kg is likely to be associated with at least one of the clinical symptoms stated above. Younger children are more susceptible to convulsions. The incidence of convulsions, in children less than 5 years, is about 60% when the oral dose ingested exceeds 40 mg/kg.
Treatment:In the management of acute overdosage with Valoid, gastric lavage and supportive measures for respiration and circulation should be performed if necessary. Convulsions should be controlled in the usual way with parenteral anticonvulsant therapy.
ATC Code: R60AE03
Pharmacotherapeutic Group: Piperazine derivatives
Mode of Action:Cyclizine is a histamine H1 receptor antagonist of the piperazine class which is characterised by a low incidence of drowsiness. It possesses anticholinergic and antiemetic properties. The exact mechanism by which cyclizine can prevent or suppress both nausea and vomiting from various causes is unknown. Cyclizine increases lower oesophageal sphincter tone and reduces the sensitivity of the labyrinthine apparatus. It may inhibit the part of the midbrain known collectively as the emetic centre.
Pharmacodynamics:Cyclizine produces its antiemetic effect within two hours and last approximately four hours.
A. Mutagenicity:Cyclizine was not mutagenic in a full Ames test, including use of S9-microsomes but can nitrosate in vitro to form mutagenic products.
B. Carcinogenicity:No long term studies have been conducted in animals to determine whether cyclizine has a potential for carcinogenesis. However, long-term studies with cyclizine administered with nitrate have indicated no carcinogenicity.
C. Teratogenicity:Some animal studies are interpreted as indicating that Cyclizine may be teratogenic. The relevance of these studies to the human situation is not known.
D. Fertility:In a study involving prolonged administration of cyclizine to male and female rats there was no evidence of impaired fertility after continuous treatment for 90-100 days. There is no experience of the effect of Valoid on human fertility.
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