Consumer medicine information

1 Name of Medicine

Promethazine hydrochloride.

2 Qualitative and Quantitative Composition

Each Fenezine 10; 10 mg tablet contains 10 mg promethazine hydrochloride.
Each Fenezine 25; 25 mg tablet contains 25 mg promethazine hydrochloride.
For the full list of excipients, see Section 6.1 List of Excipients.

3 Pharmaceutical Form

Fenezine tablets are pale blue to blue, round coated tablets, plain on both sides.

4 Clinical Particulars

4.9 Overdose

Symptoms of severe overdosage are variable. They are characterised in children by various combinations of excitation, ataxia, incoordination, athetosis and hallucinations, reversible intellectual disability and cognition deficit in children less than 6 years of age, while adults may become drowsy and lapse into coma. Convulsions may occur in both adults and children: coma or excitement may precede their occurrence. Tachycardia may develop. Cardiorespiratory depression is uncommon. The chief sign of acute poisoning from ingestion of an overdose of promethazine is unconsciousness which is commonly delayed. In addition, convulsions, hallucinations, delirium, acute anxiety, psychotic reactions, extreme hyperaesthesia and hyperalgesia with extensor plantar responses may occur. Anticholinergic action may cause tachycardia, flushed skin, dry mouth and sometimes mydriasis and urinary retention.
In adults, CNS depression is more common, with drowsiness, coma, convulsions, progressing to respiratory failure or cardiovascular collapse.
High doses can cause ventricular arrhythmias including QT prolongation and torsade de pointes (see Section 4.8 Adverse Effects (Undesirable Effects)).
In infants and children, CNS stimulation predominates over CNS depression causing ataxia, excitement, tremors, psychoses, hallucinations, convulsions and possibly hyperpyrexia, which may be followed by deepening coma and cardiorespiratory collapse.
Treatment. Similar to that of other phenothiazines. In the event of overdose of promethazine, take all appropriate measures immediately.
For information on the management of overdose, contact the Poisons Information Centre on 131126 (Australia).
Symptomatic supportive therapy is indicated and maintenance of adequate ventilation should be instituted if necessary.

5 Pharmacological Properties

5.3 Preclinical Safety Data

Genotoxicity. No data available.
Carcinogenicity. No data available.

6 Pharmaceutical Particulars

6.7 Physicochemical Properties

Promethazine hydrochloride is a white or faintly yellow, practically colourless, crystalline powder. It is very soluble in water, freely soluble in alcohol and in chloroform, and practically insoluble in ether.
Chemical structure.
https://stagingapi.mims.com/au/public/v2/images/fullchemgif/CSPROHYD.gif Chemical name: (2RS)-N,N-Dimethyl-1-(10H-phenothiazin-10-yl) propan-2-amine hydrochloride.
Molecular formula: C₁₇H₂₀N₂S.HCl.
Molecular weight: 320.88.
CAS number. 58-33-3.

7 Medicine Schedule (Poisons Standard)

S3 - Pharmacist Only Medicine.

Summary Table of Changes

https://stagingapi.mims.com/au/public/v2/images/fulltablegif/FENEZIST.gif