Consumer Information for: LIDOCAINE INJECTION BP

Usual Dose

LIDOCAINE INJECTION BP should be administered by a doctor. The dose to be given is decided by the doctor, based on the clinical need and your physical condition.

DOSAGE AND ADMINISTRATION

Dosing Considerations

General

LIDOCAINE INJECTION BP (lidocaine hydrochloride) should only be used by or under the supervision of clinicians experienced in regional anesthesia.

Parenteral drug products should be inspected visually for particulate matter and discolouration prior to administration, whenever solution and container permit. Solutions which are discoloured or which contain particulate matter should not be administered. There have been adverse event reports of irreversible chondrolysis in patients receiving intra-articular infusions of local anesthetics following arthroscopic and other surgical procedures. LIDOCAINE INJECTION BP is not approved for this use (see WARNINGS AND PRECAUTIONS, General).

Recommended doses serve only as a guide to the amount of anesthetic required for most routine procedures. The actual volumes and concentrations to be used depend on a number of factors such as type and extent of surgical procedure, depth of anesthesia and degree of muscular relaxation required, duration of anesthesia required, and the physical condition of the patient (see Special Populations).

The lowest concentration of anesthetic and the lowest dosage needed to provide effective anesthesia should be administered. The rapid injection of a large volume of local anesthetic solution should be avoided and fractional doses should be used when feasible.

When LIDOCAINE INJECTION BP is used concomitantly with other products containing lidocaine, the total dose contributed by all formulations must be kept in mind.

Preservative containing solutions (i.e. those supplied in multidose vials) should not be used for epidural or spinal anesthesia or for any route of administration that would introduce solution into the cerebrospinal fluid. Local anesthetic solutions containing antimicrobial preservatives solutions should not be administered intra-ocularly or retro-ocularly. These solutions should not be used in doses greater than 15 mL for other types of blockades (see CONTRAINDICATIONS).

Special Populations

Lidocaine should be used with caution in patients with epilepsy, impaired cardiac conduction, bradycardia, impaired hepatic or renal function and in severe shock (see WARNINGS AND PRECAUTIONS).

Debilitated patients, elderly patients, acutely ill patients, patients with sepsis and children should be given reduced doses commensurate with their age, weight and physical condition (see WARNINGS AND PRECAUTIONS).

Recommended Dose and Dosage Adjustment

Careful aspiration before and during injection is recommended to prevent intravascular injection. The main dose should be injected slowly or in incremental doses, while closely observing the patient’s vital functions and maintaining verbal contact.

Adults: Table 2 (Recommended Dosages) summarizes the recommended volumes and concentrations of lidocaine for various types of anesthetic procedures. The dosages suggested in this table are for normal healthy adults.

Children: In children the dosage should be calculated on a weight basis up to 5 mg/kg. Individual variations occur. In children with a high body weight a gradual reduction of the dosage is often necessary and should be based on the ideal body weight. Standard textbooks should be consulted for factors affecting specific block techniques and for individual patient requirements.

The onset of anesthesia, the duration of anesthesia and the degree of muscular relaxation are proportional to the volume and concentration (i.e. total dose) of local anesthetic used. Thus, an increase in volume and concentration of lidocaine will decrease the time to onset of anesthesia, prolong the duration of anesthesia, provide a greater degree of muscular relaxation and increase the segmental spread of anesthesia. Although the incidence of side effects with lidocaine is quite low, caution should be exercised when employing large volumes and concentrations since the incidence of side effects is directly proportional to the total dose of local anesthetic agent injected. The risk of reaching a toxic plasma concentration or inducing a local neural injury must be considered when prolonged blocks and/or repeated administration are employed. In general, complete block of all nerve fibres in large nerves requires the higher concentrations of drug. In smaller nerves, or when a less intense block is required (e.g., in the relief of labour pain), the lower concentrations are indicated. The volume of drug used will affect the extent of spread of anesthesia.

Dosage Recommendations in Adults

Type of Block	Conc. (%)	Each Dose mL	Each Dose mg	Onset (min)	Duration (h) Without Epineph rine	Indication
Local infiltration	0.5	≤ 80	≤ 400	1-2	1.5-2	Surgical operations.
	1	≤ 40	≤ 400	1-2	2-3
Digital2	1	1-5	10-50	2-5	1.5-2	Surgical operations.
Intercostal (per nerve) Maximum total dose of 480 mg	1	2-5	20-50	3-5	1-2	Surgical operations, post-operative pain and fractured ribs.
Paracervical3 (each side)	1	10	100	3-5	1-1.5	Surgical operations and dilation of cervix. Obstetric pain relief.
Paravertebral (per segment)	1	3-5	30-50	5-10	1-1.5	Pain management, diagnostic.
	2	3-5	60-100	5-10	1.5-2
Pudendal (each side)	1	10	100	5-10	1.5-2	Instrumental delivery.
Intra-articular block4	0.5	≤ 60	≤ 300	5-10	0.5-1 after wash out	Arthroscopy and surgical operations.
	1	≤ 40	≤ 400	5-10
Retrobulbar3	2	4	80	3-5	1.5-2	Ocular surgery.
Peribulbar3	1	10-15	100-150	3-5	1.5-2	Ocular surgery.
Brachial plexus:						Surgical operations.
Axillary	1.0	40-50	400-500	15-30	1.5-2
Supraclavicular interscalene and Subclavian perivascular	1.0	30-40	300-400	15-30	1.5-2
Sciatic	2	15-20	300-400	15-30	2-3	Surgical operations.
3-in-1 (Femoral, obturator and lateral cutaneous)	1	30-40	300-400	15-30	1.5-2	Surgical operations.

²Without epinephrine. ³ see WARNINGS AND PRECAUTIONS. ⁴ There have been post-marketing reports of irreversible chondrolysis in patients receiving post-operative intra-articular infusion of local anesthetics. Lidocaine is not approved for this indication (See WARNINGS AND PRECAUTIONS)

Overdose

Serious side effects resulting from getting too much LIDOCAINE INJECTION BP need special treatment and the doctor treating you is trained to deal with these situations. Early signs that too much LIDOCAINE INJECTION BP has been given include:

• numbness of the lips and around the mouth,
• light-headedness or dizziness
• blurred vision
• hearing problems
• tingling in the ears

In the event of a serious overdosage or a misplaced injection, trembling, seizures or unconsciousness may occur.

If the early signs of overdosage are noticed and no further LIDOCAINE INJECTION BP is given, the risk of serious side effects occurring rapidly decreases. If you have any of these symptoms, or you think you have received too much LIDOCAINE INJECTION BP, tell your doctor immediately.

Acute systemic toxicity from local anesthetics is generally related to high plasma levels encountered during therapeutic use of local anesthetics and originates mainly in the central nervous and the cardiovascular systems (see ADVERSE REACTIONS and WARNINGS AND PRECAUTIONS). It should be kept in mind that clinically relevant pharmacodynamic drug interactions (i.e., toxic effects) may occur with lidocaine and other local anesthetics or structurally related drugs, and Class I and Class III antiarrhythmic drugs due to additive effects (see DRUG INTERACTIONS).

Symptoms

With accidental intravascular injections, the toxic effect will be obvious within 1-3 min, while with overdosage, peak plasma concentrations may not be reached for 20-30 min depending on the site of injection, with signs of toxicity thus being delayed.

Central nervous system toxicity is a graded response, with symptoms and signs of escalating severity. The first symptoms are circumoral paresthesia, numbness of the tongue, light-headedness, hyperacusis and tinnitus. Visual disturbance and muscular tremors are more serious and precede the onset of generalized convulsions. Unconsciousness and grand mal convulsions may follow, which may last from a few seconds to several minutes. Hypoxia and hypercarbia occur rapidly following convulsions due to the increased muscular activity, together with the interference with normal respiration. In severe cases apnea may occur. Acidosis, hyperkalaemia, hypocalcaemia and hypoxia increase and extend the toxic effects of local anesthetics.
Recovery is due to redistribution and metabolism of the local anesthetic drug. Recovery may be rapid unless large amounts of the drug have been administered.

Cardiovascular effects may be seen in cases with high systemic concentrations. Severe hypotension, bradycardia, arrhythmia and cardiovascular collapse may be the result in such cases.

Cardiovascular toxic effects are generally preceded by signs of toxicity in the central nervous system, unless the patient is receiving a general anesthetic or is heavily sedated with drugs such as a benzodiazepine or barbiturate.

Treatment

The first consideration is prevention, best accomplished by careful and constant monitoring of cardiovascular and respiratory vital signs and the patient’s state of consciousness after each local anesthetic administration. At the first sign of change, oxygen should be administered. If signs of acute systemic toxicity appear, injection of the local anesthetic should be immediately stopped.

The first step in the management of systemic toxic reactions, as well as under ventilation or apnea due to unintentional subarachnoid injection consists of immediate attention to the establishment and maintenance of a patent airway and assisted or controlled ventilation with oxygen and a delivery system capable of permitting immediate positive airway pressure by mask. This may prevent convulsions if they have not already occurred.

If convulsions occur, the objective of the treatment is to maintain ventilation and oxygenation and support circulation. Oxygen must be given and ventilation assisted if necessary (mask and bag or tracheal intubation). Should convulsions not stop spontaneously after 15-20 seconds, an anticonvulsant should be given iv to facilitate adequate ventilation and oxygenation. Thiopental sodium 1-3 mg/kg iv is the first choice. Alternatively diazepam 0.1 mg/kg bw iv may be used, although its action will be slow. Prolonged convulsions may jeopardise the patient's ventilation and oxygenation. If so, injection of a muscle relaxant (e.g. succinylcholine 1 mg/kg bw) will facilitate ventilation, and oxygenation can be controlled. Early endotracheal intubation is required when succinylcholine is used to control motor seizure activity.

If cardiovascular depression is evident (hypotension, bradycardia), ephedrine 5-10 mg i.v. should be given and may be repeated, if necessary, after 2-3 minutes.

Should circulatory arrest occur, immediate cardiopulmonary resuscitation should be instituted. Continual oxygenation and ventilation and circulatory support as well as treatment of acidosis are of vital importance, since hypoxia and acidosis will increase the systemic toxicity of local anesthetics.