Avoca Caustic Pencil

Avoca Silver Nitrate Caustic Pencils are designed for multiple use for a single patient.

An Avoca Pencil contains approximately 350mg of silver nitrate & potassium nitrate mixture.

This is about 10 times more silver nitrate than an applicator.

This red carton and red plastic holder signals a 40% silver nitrate mixture. 

From the date of manufacture, all Avoca Pencils have a 5-year shelf life.

Side effects of silver nitrate include:

burning and skin irritation
staining of the skin
blood disorder (methemoglobinemia)

Before taking any medication, it is important to read the Patient Information Leaflet. You can find information leaflets for your medicines by typing them into the search bar at medicines.org, or by contacting us.

Please read the package leaflet carefully before use.

Recommended dose is :

Apply once daily for 3 days for wart treatment

Apply once daily for 6 days for verruca treatment 

Since the tips of applicators and pencils are small and standardised, there is less of a risk of excess being applied accidentally. Silver nitrate is a hazard due to its causticity, and is toxic when taken by mouth. However, absorption of silver nitrate through intact skin is negligible. Due to its chemical reactivity and the fact that it is metabolically highly refractory, there is a low risk of systemic toxicity if applied externally.The moistened point is applied directly to the wart for one to two minutes. Treatment may be repeated after 24 hours to a maximum of 3 applications Applied topical to area to be treated.

The active substance is silver nitrate
The other ingredient is potassium nitrate