AMPRES 20 mg/ml Solution for injection Ref.[50493] Active ingredients: Chloroprocaine

The equipment, medicinal products and personnel capable of dealing with an emergency, e.g. maintaining the patency of the airways and administering oxygen, must be immediately available, since in rare cases severe reactions, sometimes with a fatal outcome, have been reported after using local anaesthetics, even in the absence of individual hypersensitivity in the patient’s case history. The doctor in charge is responsible for taking the measures needed to avoid an intravascular injection and should be fully trained in emergency medicine and resuscitation to be ready to prevent and treat the undesirable effects and complications of the procedure.

Posology

Posology must be established on an individual basis in accordance with the characteristics of the specific case. When determining the dose, the patient’s physical condition and the concomitant administration of other medicinal products should be taken into consideration.

The dose administered varies with the anaesthetic procedure, the vascularity of the tissues, the depth of anaesthesia and degree of muscle relaxation required, the duration of anaesthesia desired, and the physical condition of the patient.

The following table is a guide to dosage for the more commonly used blocks. The smallest dose required to produce an effective block should be used.

Posology Adults

^* With regard to major nerve block, only for axillary block a dose recommendation can be given. There is presently no experience of specific dose recommendations for other blocks and the posology must be established on an individual basis

The maximum recommended dose in adults is 11 mg/kg, not to exceed a maximum total dose of 800mg (=40ml) of chloroprocaine hydrochloride.

The duration of action is dose-dependent.

Special population

The clinician’s experience and knowledge of the patient’s physical status are of importance when deciding the dose. It is advisable to reduce the dose in patients in a compromised general condition.

In addition, for elderly patients, in patients with established concomitant disorders (e.g. vascular occlusion, arteriosclerosis, diabetic polyneuropathy) a reduced dose is indicated.

Paediatric population

The safety and efficacy of Ampres in children and adolescents have not been established. No data are available (see section 5.1).

Method of administration

For Perineural use (peripheral nerve block).

Chloroprocaine may be given as a single dose administration.

The medicinal product has to be visually inspected prior to use. Only clear solutions practically free from particles should be used. The intact container must not be re-autoclaved.

It is unlikely that Ampres, at the recommended posology by perineural administration, will induce plasma levels capable of inducing systemic toxicity (see section 5.2).

Acute systemic toxicity

Systemic undesirable effects are of methodological (due to use), pharmacodynamic or pharmacokinetic origin and concern the central nervous system and the cardiocirculatory system.

Iatrogenic undesirable effects occur:

• after injecting an excessive quantity of solution
• from accidental injection into a vessel

In the case of accidental intravenous administration, the toxic effect occurs within 1 minute. The intravenous LD₅₀ of chloroprocaine HCl is 97 mg/kg in mice, 65 mg/kg in guinea pigs and <30 mg/kg in dogs, corresponding to human equivalent doses of 7.9 mg/kg, 14.1 mg/kg and < 16.7 mg/kg, respectively. The subcutaneous LD₅₀ of chloroprocaine HCl in mice is 950 mg/kg, . corresponding to human equivalent dose of 77.2 mg/kg,

Signs of overdose can be classified into two different sets of symptoms which differ in terms of quality and intensity:

Symptoms affecting the central nervous system

Generally, the first symptoms are paresthesia in the mouth area, feeling of numbness of the tongue, feeling dazed, problems with hearing and tinnitus. Visual problems and muscle contractions are more severe and precede a generalized convulsion. These signs must not be erroneously mistaken for neurotic behaviour. Subsequently loss of consciousness and tonic-clonic seizure may occur, generally lasting between a few seconds and a few minutes. The convulsions are immediately followed by hypoxia and increased levels of carbon dioxide in the blood (hypercapnia), attributable to increased muscular activity associated with respiratory problems. In serious cases respiratory arrest may occur. Acidosis and/or hypoxia potentiate the toxic effects of local anaesthetics.

The reduction or improvement of symptoms affecting the central nervous system can be attributed to the redistribution of local anaesthetic outside the CNS, with its consequent metabolism and excretion. Regression may be rapid, unless enormous quantities have been used.

Cardiovascular symptoms

In serious cases cardiovascular toxicity may occur. Hypotension, bradycardia, arrhythmia and also cardiac arrest may occur in the presence of a high systemic concentration of local anaesthetics.

The first signs of toxic symptoms affecting the central nervous system generally precede toxic cardiovascular effects. This statement does not apply if the patient is under general anaesthesia or heavily sedated with medicinal products such as benzodiazepine or barbiturates.

Treatment of acute systemic toxicity

The following measures must be taken immediately:

• Administration of Ampres must be stopped.
• An adequate supply of oxygen must be ensured: the airways should be kept clear, O₂ should be administered, artificial ventilation (intubation) if required.
• In case of cardiovascular depression circulation must be stabilized.

If convulsions occur and do not resolve spontaneously after 15-20 seconds, the administration of an intravenous anticonvulsant is recommended.

Analeptics with a central action are contraindicated in the case of intoxication caused by local anaesthetics!

In the event of serious complications, when treating the patient it is advisable to obtain the assistance of a doctor specializing in emergency medicine and resuscitation (e.g. anaesthetist).

In patients with genetic deficiency of plasma cholinesterase an intravenous lipid solution could be administered.

2 years.

The medicinal product has to be used immediately after first opening.

Do not store above 25°C. Do not refrigerate or freeze. Keep the vial in the outer carton, in order to protect from light.

Type I clear colourless glass 20 ml vial.

Box of 1 vial containing 20 ml of solution for injection.

Any unused medicinal product or waste material should be disposed of in accordance with local requirements.