Summary of Product Characteristics (SmPC) - Avoca Caustic Applicator 75% w/w cutaneous Stick
1 NAME OF THE MEDICINAL PRODUCT
Avoca Caustic Applicator 75% w/w Cutaneous Stick
2 QUALITATIVE AND QUANTITATIVE COMPOSITION
Silver Nitrate
For a full list of excipients, see section 6.1.
3 PHARMACEUTICAL FORM
Cutaneous stick
4 CLINICAL PARTICULARS
4.1 Therapeutic indications
Used for removing granulation tissue, warts (including verrucae), for cautery and as a caustic.
4.2 Posology and method of administration
For topical use only – not to be taken
The tip is moistened with suitably clean water and applied topically to the area to be treated. Surrounding areas of healthy skin, etc. should be protected from the caustic/staining action of silver nitrate by a suitable barrier such as petroleum jelly, where necessary and practicable.
4.3 Contraindications
Hypersensitivity to the silver nitrate or to the excipient potassium nitrate.
Not for use near the eyes or other sensitive areas of the body, due to the corrosive / staining action of the product.
Should not be used for genital warts
4.4 Special warnings and precautions for use
Must be used under medical supervision. The instruction must be followed in view of the caustic/staining nature of the product.
Paediatric population
No data are available
4.5 Interaction with other medicinal products and other forms of interaction
No interaction studies have been performed.
4.6 Pregnancy and lactation
None
4.7 Effects on ability to drive and use machines
None
4.8 Undesirable effects
Skin and subcutaneous tissue disorders
Chronic application of silver nitrate or its products to conjunctive, mucous membranes or open wounds may lead to a condition known as argyria, an accumulation of silver metal or compounds in the connective tissues which gives rise to a local or general bluish-black appearance. This is thought to be a completely harmless cosmetic effect only, but it may persist indefinitely or disappear only very slowly.
Absorption of nitrate following reduction of nitrate by certain bacteria in some wounds may cause methaemoglobinaemia. There is a risk of electrolyte disturbances.
Cases of either argyria or methaemoglobinaemia are very rare (<1/10,000) and are likely to arise only under exceptional circumstances of prolonged use of large quantities of sliver nitrate.
Paediatric population
No data are available
Reporting of suspected adverse reactions
Reporting suspected adverse reactions after authorisation of the medicinal product is important. It allows continued monitoring of the benefit/risk balance of the medicinal product. Healthcare professionals are asked to report any suspected adverse reactions via the national reporting system:
United Kingdom
Yellow Card Scheme
Website: www.mhra.gov.uk/yellowcard
or search for MHRA Yellow Card in the Google Play or Apple App Store
4.9 Overdose
Excessive quantities given or incorrect use in topical application may give rise to burning or staining.
Accidental poisoning by ingestion is unlikely with the small quantities involved, but symptoms that do arise are due to the corrosive nature of silver nitrate. There may be pain in the mouth sialorrhoea, diarrhoea, nausea, vomiting, coma or convulsions. Tissues and vomit will be stained black.
Treatment for accidental or intentional poisoning by ingestion should be commenced without delay. This should be by washing out the stomach repeatedly with 1 % sodium chloride solution. After this lavage a purgative should be given, such as 30 g of sodium sulphate in 250 ml of water, to be allowed to remain in the stomach. Demulcents such as egg-white, milk or liquid paraffin may be administered, with pethidine or morphine if necessary. Close attention must be paid to renal function and fluid balance.
Paediatric population
No data are available
5 PHARMACOLOGICAL PROPERTIES
5.1 Pharmacodynamic properties
Pharmacotherapeutic group: silver compounds, ATC code: D08AL01
Silver nitrate acts as a caustic to remove unwanted tissue and destroy warts, verrucae and other small skin growths.
5.2 Pharmacokinetic properties
Absorption
Absorption of silver nitrate is negligible via intact skin, and poor through most mucus membranes. It is known to be absorbed more efficiently via the gastrointestinal tract. The nitrate ion, produced in some instances by the action of nitrate-reducing bacteria on the substance from open wounds, etc, may give rise to methaemoglobinaemia, in extreme cases especially if large quantities of the product are used.
Distribution
Silver has no known physiological function. This substance is biologically very refractory and is metabolised with difficulty. Any sizeable quantities that are absorbed later redistribute, mainly as deposits of silver metal and insoluble compounds, about the various organs of the body, principally within the connective tissues.
Accumulation is especially predominant within the skin and mucous membranes.
Biotransformation
No data are available
Elimination
Topically applied silver nitrate is generally shed, eventually, externally from the original site of topical administration by desquamation. Systemic excretion is very slow and is reported to be almost exclusively faecal.
Linearity/non-linearity
No data are available
Pharmacokinetic/pharmacodynamic relationship(s)
No data are available
5.3 Preclinical safety data
There are no preclinical safety data of significance to the prescriber which are not already included in the SPC.
6 PHARMACEUTICAL PARTICULARS
6.1 List of excipients
Potassium Nitrate
6.2 Incompatibilities
Silver nitrate is chemically incompatible with a number of substances such as certain organic chemicals, with which it may present a risk of fire or explosion due to its oxidising properties. Sliver nitrate will also form insoluble precipitators with some anions, e.g. chloride, which may for example be present in tap water, and so lose part or all of its activity.
6.3 Shelf life
5 years
6.4 Special precautions for storage
Store in the original package to protect from light and moisture.
6.5 Nature and contents of container
Box containing 50 or 100 applicators in plastic bags of 10. Each applicator is a 15cm long flexible plastic handle with a treated tip.
6.6 Special precautions for disposal and other handling
The flexible plastic handle may be shaped according to the particular application as required. The tip is moistened with suitably clean water and applied topically to the tissue to be treated for 1 to 2 minutes. Do not moisten the tip using saline solution.
It must be used precisely according to the instructions due to the corrosive and staining nature of the material.
Any unused medicinal product or waste material should be disposed of in accordance with local requirements.
7 MARKETING AUTHORISATION HOLDER
Bray Group Ltd
1 Regal Way
Faringdon
Oxfordshire
SN7 7BX
8 MARKETING AUTHORISATION NUMBER(S)
PL 04286/0004
9 DATE OF FIRST AUTHORISATION/RENEWAL OF THE
AUTHORISATION
Date of first authorisation – 29 October 1982 Date of renewal – 25 January 1995
10 DATE OF REVISION OF THE TEXT
17/03/2019