Other Ester Anaesthetics
Moderate
Database
Class cross-hypersensitivity
Avoid if known ester-anaesthetic allergy
Source: Kimi deep-research + Cla
Drug reference
butylaminobenzoate
Ester-type local anaesthetic (butamben) · Local Anaesthetic
START
Topical 1% ointment/cream to affected area
TYPICAL MAX
Topical to small area as needed
STOP IF
Severe contact dermatitis or hypersensitivity
WATCH
Avoid extensive use; PABA / sulfonamide allergy history
CDSCO approvedATC N01BA08
KDIGO 2024 + manufacturer label
- ONSET
- 6min · numbing
- PEAK
- 30min · local peak
- t½
- 36s · topical
- DURATION
- 4h · topical action
EXCRETION
Local; renal PABA if absorbed
route + CYP
INTERACTIONS
—
none in our sources
PREGNANCY
Limited data; topical use acceptable.
FDA category + note
Mechanism
Ester local anaesthetic (PABA derivative) that reversibly blocks voltage-gated sodium channels in neuronal membranes, preventing depolarisation and nerve conduction — long-duration topical anaesthesia.
Indications
Topical anaesthesia (skin, mucous membranes)Otic preparations (rarely used)Adjunct for painful skin / oral lesions
Dosing
- Adult
- Topical: 1% ointment / cream applied to affected area as needed.
- Pediatric
- Avoid extensive use; same topical principles.
- Renal adjustment
- No adjustment (topical).
- Hepatic adjustment
- No adjustment.
- Geriatric
- Standard topical use.
- Max dose
- Topical; limit area to avoid systemic absorption
Pharmacokinetics
Onset
~5–15 min topical numbing
Peak effect
Within 30 min
Duration
Long topical action (hours)
Half-life
Not applicable (topical; rapid esterase hydrolysis if absorbed)
Bioavailability
Very low systemic
Protein binding
Moderate (if absorbed)
Metabolism
Plasma cholinesterase hydrolysis (ester)
Excretion
Renal (PABA conjugates)
Contraindications
- Hypersensitivity to ester local anaesthetics (PABA derivatives)
- Sulfonamide cross-hypersensitivity (caution)
- Application to extensively broken skin / large areas
Side effects
Common
Local irritationContact dermatitis (PABA cross-reaction)Burning sensation
Serious
- Severe hypersensitivity (PABA / sulfonamide cross)
- Methaemoglobinaemia (rare; with related ester anaesthetics)
- Local skin necrosis (rare)
Pregnancy & lactation
Pregnancy
Limited data; topical use acceptable.
Lactation
Limited systemic absorption; compatible.
Drug interactions
Sulfonamide Antibiotics
Moderate
Database
PABA-derivative antagonism (theoretical)
Avoid coadministration if topical use extensive
Source: Kimi deep-research + Cla
Sulfonamides
Mild
Textbook
Can antagonize sulfonamides locally.
Not explicitly stated, but implies avoiding concurrent local application where sulfonamide efficacy is critical.
Source: KDT 7e · p367
Antimicrobials
Mild
Database
Theoretical PABA interaction
Standard care
Source: Kimi deep-research + Cla
Methaemoglobin Inducing Drugs
Mild
Database
Class methaemoglobinaemia risk
Avoid stacking; especially in infants
Source: Kimi deep-research + Cla
Sunscreens
Mild
Database
Same PABA cross-reactivity
Avoid in PABA-allergic patients
Source: Kimi deep-research + Cla
Related guidelines
Ask House about butylaminobenzoate
Continue into a citation-backed clinical answer with the drug context already attached.
Sources: KD Tripathi 7e·Verified: 2026-05-20 · House clinical team·Cockpit curated: 2026-05-20