UNCONTROLLED WHEN PRINTED

Introduction

Cophenylcaine presents as a 50ml bottle of clear medication (approximately 500 sprays). Each spray contains 5mg Lignocaine and 0.5mg Phenylephrine.

Lignocaine is a local anaesthetic and phenylephrine is a sympathomimetic agent.

Lignocaine stabilises the neuronal membrane and prevents initiation and transmission of nerve impulses, thereby effecting local anaesthetic action.

Phenylephrine has direct effects on the alpha adrenoceptors. It constricts the blood vessels locally, which can decrease the systemic absorption of lignocaine and restrict bleeding.

Uses within SJA

Local pain caused by abrasions, small cuts and wounds, relief of mild and moderate epistaxis, post tonsillectomy haemorrhage and intra-oral haemorrhage.

Pharmacokinetics

Onset

Onset of action is rapid (one to five minutes) and may last for up to one hour. Absorption: Through the nasal and oral mucous membranes and skin when applied topically.

Distribution

The liver is the chief site of biotransformation (chemical modification) yet the lignocaine component of cophenylcaine is dispersed through interstitial fluid and across neuronal membranes by lipid diffusion.

Metabolism

In the liver

Excretion

Both free and conjugated forms of the drug are excreted in the urine.

Pharmacodynamics

Desired Effects

  • Lignocaine stabilises all potentially excitable membranes and prevents the initiation and transmission of nerve impulses, therefore producing a local anaesthetic effect.
  • Phenylephrine acts predominantly on alpha-adrenergic receptors and is mainly used in the prehospital environment for is vasoconstrictive effects.

Side Effects

Rarely causes tremor or palpitations, nervousness, nausea, vomiting, tinnitus, dizziness, numbness or disorientation may occur due to rapid absorption of Lignocaine.

The most commonly noted side effect is a transient bitter taste in the mouth lasting onto two minutes.

Duration of Action

Onset of action is rapid and drug effects may last from 60 to 90 minutes.

Other Drug Interactions

Propranolol or cimetidine may reduce the clearance of lignocaine.


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