lidocaine hydrochloride + zinc oxide: clinical use

Prescribing considerations

• Confirm that bleeding, pain or a perianal lesion does not require investigation for another cause.
• Persistent, recurrent or severe haemorrhoids and excessive bleeding require medical assessment.
• Systemic effects are considered unlikely during intended local use, but accidental ingestion requires medical advice.

Contraindications and cautions

• Hypersensitivity to lidocaine, zinc oxide or any formulation excipient.

Monitoring

• No routine laboratory monitoring is specified.
• Review symptom response and check for local irritation, burning, rash or contact dermatitis.

Clinical pharmacology

Lidocaine provides local anaesthesia and has a rapid onset. It is partly absorbed locally, but expected plasma concentrations are low; absorbed lidocaine undergoes hepatic de-ethylation. Zinc oxide contributes astringent, soothing and protective effects.

Formulation and product differences

• Cream and ointment are suitable for topical and rectal administration using an applicator; suppositories are for rectal administration and principally address internal symptoms.
• The cream is water-containing and emollient; its methyl hydroxybenzoate may cause delayed allergic reactions.
• The ointment has a more lubricating base and contains lanolin and propylene glycol, which can cause local skin reactions.
• Suppositories use a hard-fat base with lubricating and emollient properties.