Covonia Throat Spray

1. Name Of The Medicinal Product

Covonia Throat Spray

2. Qualitative And Quantitative Composition

Chlorhexidine gluconate 0.2% w/v

Lidocaine hydrochloride 0.05% w/v

For excipients, see 6.1.

3. Pharmaceutical Form

Oromucosal spray

4. Clinical Particulars

4.1 Therapeutic Indications

Covonia Throat Spray is indicated for the symptomatic relief of painful, irritated sore throats.

It is a sugar free preparation and can be used by diabetics.

Additional therapy is required in the event of bacterial infection accompanied by fever.

4.2 Posology And Method Of Administration

Adults and children over 12 years

The dose is 3 to 5 sprays (0.3 - 0.5 ml). This can be repeated 6 to 10 times per day.

Children under 12 years

Not recommended.

4.3 Contraindications

Use in children under 12 years.

Hypersensitivity to chlorhexidine, lidocaine or other local anaesthetics of the amide type, or any of the other ingredients.

4.4 Special Warnings And Precautions For Use

Treatment with Covonia Throat Spray should be limited to the relief of existing pain and irritation when strictly necessary. It is not intended for prolonged use, either continuously or repeatedly.

This medicine contains 42.5 vol % ethanol (alcohol), i.e. up to 168mg per application (5 sprays), equivalent to 0.85ml beer or 0.35ml wine per dose.

Each 10 ml of the throat spray contains 3.5 g of ethanol.

The use of Covonia Throat Spray should be avoided in individuals with a history of significant allergy.

Do not use and consult your doctor if you have difficulty in swallowing. Do not use without consulting your doctor if sore throat is severe or has lasted for more than 2 days or is accompanied by high fever, headache, nausea or vomiting.

Avoid contact with eyes.

4.5 Interaction With Other Medicinal Products And Other Forms Of Interaction

Chlorhexidine is not known to interact with other drugs.

Whilst a number of interactions are theoretically possible with lidocaine these drug interactions are not likely to be clinically relevant to the use of Covonia Throat Spray which is administered topically. Concomitant therapy with drugs that reduce hepatic blood flow (e.g. propranolol, cimetidine) may reduce the clearance of lidocaine. Long term administration with drugs that induce drug-metabolising microsomal enzymes (e.g. phenytoin, barbiturates) may increase dosage requirements of lidocaine. The cardiac depressant effects of lidocaine are additive with those of beta blockers and other anti-arrhythmics (e.g. mexiletine). Lidocaine is a weak inhibitor of pseudocholinesterase and may prolong the action of suxamethonium. Hypokalaemia produced by acetazolamide, loop diuretics and thiazides may antagonise the effect of lidocaine.

4.6 Pregnancy And Lactation

There is inadequate evidence of the safety of lidocaine and chlorhexidine in human pregnancy but they have been in wide use for many years without apparent ill consequence. Covonia Throat Spray should only be used in pregnancy and breast feeding under the direction of a physician.

Lidocaine is excreted in breast milk but in such small quantities that there is generally no risk of the infant being affected at therapeutic dose levels.

4.7 Effects On Ability To Drive And Use Machines

No significant effects are known.

4.8 Undesirable Effects

Chlorhexidine and lidocaine are usually well tolerated and no unwanted effects have been reported for the product during local short term use.

In extremely rare cases local anaesthetic preparations have been associated with allergic reactions. Hypersensitivity reactions to lidocaine hydrochloride following local injection have presented as localised oedema with slight difficulty in breathing or as a generalised rash.

Chlorhexidine may sometimes produce discoloration of the teeth and tongue. This is not permanent and disappears after treatment when chlorhexidine is discontinued. Occasionally, a dental scale and polish may be necessary to remove the stain completely. Skin sensitivity to chlorhexidine has occasionally been reported, and severe hypersensitivity reactions, including anaphylactic shock, have been reported on rare occasions following the topical use of chlorhexidine. Chlorhexidine may cause transient taste disturbances, a burning sensation of the tongue, and occasional parotid gland swelling.

4.9 Overdose

The use of oral topical anaesthetic agents may interfere with swallowing and thus enhance the danger of aspiration of food in the respiratory tract. To this end, overdosage with Covonia Throat Spray (use of 10 ml or more) could produce a slight risk of inducing too great a local anaesthetic effect in the glottis region and consequent reduction in control of the swallowing reflex.

Excessively high blood concentrations of lidocaine may produce CNS and/or cardiovascular effects. Early CNS effects may consist of nervousness, dizziness, tinnitus, nystagmus, restlessness, excitation, paraesthesia, blurred vision, nausea, vomiting, and tremors which may progress to medullary depression and tonic and clonic convulsions. Cardiovascular reactions are depressant and may be characterised by hypotension, myocardial depression, bradycardia and possibly cardiac arrest.

Although the bioavailability of lidocaine is low it may be sufficient to result in significant toxicity when swallowed. CNS toxicity, seizures and death have been reported following the ingestion of topical preparations. However, in the case of Covonia Throat Spray more than one litre would have to be swallowed to be equivalent to the ingestion of sufficient lidocaine (0.5 g or more) to cause significant toxicity.

Systemic toxicity from chlorhexidine is rare. The main consequence of ingestion is mucosal irritation.

Treatment of lidocaine overdosage consists of ensuring adequate ventilation and arresting convulsions. Ventilation should be maintained with oxygen by assisted or controlled respiration as required. Convulsions may be treated with thiopentone, diazepam or succinylcholine. As succinylcholine will arrest respiration it should only be used if the clinician has the ability to perform endotracheal intubation and to manage a totally paralysed patient. If ventricular fibrillation or cardiac arrest occurs, effective cardiovascular resuscitation must be instituted. Adrenaline in repeated doses and sodium bicarbonate should be given as rapidly as possible.

5. Pharmacological Properties

5.1 Pharmacodynamic Properties

Lidocaine is a local anaesthetic of the amide type. Like other local anaesthetics, lidocaine impairs the generation and conduction of the nerve impulses by slowing depolarisation. This results from blocking of the large transient increase in permeability of the cell membrane to sodium ions that follows initial depolarisation of the membrane. Lidocaine also reduces the permeability of the resting axon to potassium and to sodium ions.

Chlorhexidine is a bisbiguanide antiseptic and disinfectant which is bactericidal or bacteriostatic against a wide range of Gram-positive and Gram-negative bacteria. It is more effective against Gram-positive than Gram-negative bacteria and some species of Pseudomonas and Proteus have low susceptibility. It is relatively ineffective against mycobacteria. It inhibits some viruses and is active against some fungi.

5.2 Pharmacokinetic Properties

Covonia Throat Spray is applied topically for local action in the throat. On swallowing the spray solution or saliva, small amounts may reach the digestive system and some may be absorbed from the oral and pharyngeal mucosa.

Lidocaine is readily absorbed from oral mucous membranes, the gastrointestinal tract and through damaged skin. Absorption through intact skin is poor. Presystemic metabolism is extensive and bioavailability is only about 35% after oral administration. Following absorption, lidocaine is rapidly distributed to all body tissues. It crosses the placenta and blood-brain barrier. Approximately 65% is bound to plasma protein. It has a plasma half-life of 1.6 hours. Lidocaine is largely metabolised in the liver. Any alteration in liver function or hepatic blood flow can have a significant effect on its pharmacokinetics and dosage requirements. Metabolism in the liver is rapid and approximately 90% of a given dose is dealkylated to form monoethylglycinexylidide (MEGX) and glycinexylidide (GX); both of which may contribute to its therapeutic and toxic effects. Further metabolism occurs and metabolites are excreted in the urine with less than 10% of unchanged lidocaine.

Chlorhexidine is poorly absorbed from mucous membranes, intact skin and the gastrointestinal tract. It is only minimally metabolised by the liver and is excreted through bile. Urinary excretion is very low.

5.3 Preclinical Safety Data

There are no further relevant data.

6. Pharmaceutical Particulars

6.1 List Of Excipients

Citric acid monohydrate

Glycerol

Saccharin sodium

Menthol, racemic

Eucalyptol

Ethanol (96%)

Purified water

6.2 Incompatibilities

Not applicable.

6.3 Shelf Life

Five Years.

6.4 Special Precautions For Storage

Do not store above 25°C.

6.5 Nature And Contents Of Container

Brown, type III glass (E.P.) bottle with a pump, polypropylene cannula, polyethylene dip tube and polyethylene screw cap.

6.6 Special Precautions For Disposal And Other Handling

Not applicable.

7. Marketing Authorisation Holder

Thornton & Ross Ltd

Linthwaite

Huddersfield

HD7 5QH

United Kingdom

8. Marketing Authorisation Number(S)

PL 00240/0043

9. Date Of First Authorisation/Renewal Of The Authorisation

06/02/2009

10. Date Of Revision Of The Text

28/01/2010