Lidocaine + Epinephrine

Indications

Lidocaine + Epinephrine is used for: Local or regional anaesthesia, nerve blocks, epidural and caudal anaesthesia

Adult Dose

Injection Local or regional anaesthesia, nerve blocks, epidural and caudal anaesthesia Adult: Per ml prep contains lidocaine HCl 20 mg and epinephrine 5 mcg. Dosage depends on several factors such as route, type and extent of surgical procedure, duration of anaesthesia and patient's condition and age. Max dose of lidocaine given with epinephrine: 7 mg/kg and not >500 mg.

Child Dose

Injection Local or regional anaesthesia, nerve blocks, epidural and caudal anaesthesia Child: 3 mth-12 yr: Per ml prep contains lidocaine HCl 20 mg and epinephrine 5 mcg. Dosage depends on several factors such as route, type and extent of surgical procedure, duration of anaesthesia and patient's condition and age. Max dose 3 mg/kg. Ideal body weight should be used in children with high body weight.

Renal Dose

Administration

Contra Indications

Tachycardia, hypertension, cerebral arteriosclerosis, ischaemic heart disease, IV admin, anaesthetise digits or appendages, myasthenia gravis.

Precautions

Epilepsy, impaired cardiac conduction, CHF, DM, closed angle glaucoma, impaired liver function (if site of admin is likely to result in high blood levels), severe renal dysfunction. Local anaesthetic effect may be reduced if injected into an inflamed or infected area. Cerebrovascular insufficiency, hyperthyroidism. Neonates, elderly, patients in poor general condition (optimise patient's condition before major block), pregnancy.

Pregnancy-Lactation

Interactions

Significance of interaction depends on route of delivery and systemic exposure; lidocaine prolongs duration of action of suxamethonium; benzodiazepines & barbiturates raise the convulsive threshold to lidocaine; vasopressors potentiate pressor effects of adrenaline; BP may increase with non-selective β-blockers, TCAs, halogenated inhalational anaesthetics and α-blockers; general anaesthetics may increase sensitivity of myocardium to dysrhythmic effects of epinephrine; lidocaine may increase levels and effects of benzodiazepines, calcium channel blockers, ciclosporine, aminophylline, fluvoxamine, mexiletine, mirtazapine, ropinirole, theophylline, trifluoperazine, dextromethorphan, fluoxetine, nefazodone, paroxetine, risperidone, TCAs and venlafaxine. Levels and effects of lidocaine may be increased by propranolol, chlorpromazine, delavirdine, fluoxetine, miconazole, pergolide, quinidine, quinine, ritonavir, ropinirole, cimetidine, azole antifungals, clarithromycin, diclofenac, doxycycline, erythromycin, isoniazid, nicardipine and verapamil. Lidocaine may decrease levels and effects of codeine, hydrocodone, oxycodone, tramadol, carbamazepine, nafcillin, nevirapine, phenobarbital, phenytoin and rifamycins. Midazolam, cisapride, ergot alkaloids, lovastatin and simvastatin are not recommended in combination with lidocaine.

Adverse Effects

Side effects of Lidocaine + Epinephrine : Severity of adverse effects in CNS and CVS are directly related to blood levels of lidocaine; the effects are more likely to occur after systemic administration rather than infiltration; dizziness; muscle twitching; local anaesthetic of mouth/throat impairs swallowing and increases the risk of aspiration (patients cautioned against eating or drinking for 3-4 hr after anaesthesia); transient effect on auditory system of neonate; erythema; pigmentation; pain; headache; palpitations; local necrosis; pulmonary oedema; hyperglycaemia; bradycardia; reduced cardiac output; anxiety. Epidural may cause hypotension, bradycardia, nausea and vomiting. Intraoral inj may cause stress reactions such as diaphoresis, palpitation, hyperventilation, generalised pallor and faintness. Potentially Fatal: Severity of adverse effects in CNS and CVS related to blood levels of lidocaine; effects more likely to occur after systemic administration rather than infiltration. CNS toxicity (due to inadvertent IV admin), medullary depression with tonic & clonic convulsions; ventricular fibrillation; severe hypertension with cerebral haemorrhage and pulmonary oedema; unconsciousness; possibly respiratory arrest. Allergic reactions including anaphylactic symptoms and possibly life threatening asthmatic episodes in susceptible patients may occur due to sodium metabisulphate constituent. Central nerve blocks may cause CV depression (especially in hypovolaemia).

Mechanism of Action

Lidocaine is a local anaesthetic which decreases permeability of sodium ions, blocking induction and conduction of nerve impulses. Combination with epinephrine restricts systemic spread of lidocaine, vascular absorption and its duration of local anaesthetic effect.