Dapsone

ACZONE

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Pronunciation: DAP-soen (AK-zoen)

Dapsone ballicule: receptor binding, kinetics and half-life diagram — Mechanism of action: Dapsone ballicule

What it isSulfone inhibiting dihydropteroate synthase; leprosy, dermatitis herpetiformis and PJP prophylaxis.

Why this oneThe treatment of choice for dermatitis herpetiformis, with a response within days.

What limits itHemolysis, severe in G6PD deficiency, and methemoglobinemia. Check G6PD before starting.

Dapsone molecular structure (skeletal formula) — Molecular structure: Dapsone

Dapsone prescription history

Animated chart of estimated U.S. prescriptions per year, Acne meds (topical) (1900–2026). Dapsone enters in 2008 (estimated).

FDA-approved for

leprosy/dermatitis herpetiformis (~1955)

Principal riskHemolysis, severe in G6PD deficiency

Sulfonamide

Aromatic-amine drug (not a sulfonamide)

A sulfone (SO₂ between two carbons), not a sulfonamide — but each phenyl ring carries an aromatic amine, so the hydroxylamine/nitroso route is open. Cross-reactivity data conflict; Khan suggests avoidance, especially after severe reactions. In HIV patients with TMP-SMX intolerance it is often tolerated: all 13 given dapsone in one series did⁴.

Open the sulfonamide hypersensitivity presentation → · sources [n] are on its References slide.

Classes and tags

Clinical profile

Therapeutic safety burden1 / 4

Overdose danger1 / 4

Weight-gain liability0 / 4

Sedation liability0 / 4

QT / Torsades0 / 4

Direct muscarinic antagonism0 / 4

Embryofetal risk1 / 4

Legacy pregnancy categoryUnknown / historical label unavailable

Defining liabilityGenerally tolerated at therapeutic doses; clinically important risks are agent-specific and increase with interactions or organ impairment.

FDA label

Read the full label on DailyMed ↗

NO BOXED WARNINGS

FDA dosing	Population	Start	Target	Max
Acne vulgaris (topical)	Adults & children ≥9 yr	Pea-sized amount, thin layer to entire face QD (thin layer to other affected areas QD)	Same, QD	QD

Renal Undefined

Hepatic Undefined

Instructions

Topical only — not for oral, ophthalmic, or intravaginal use
Apply to gently washed, patted-dry skin; rub in gently and completely
Reassess if no improvement after 12 weeks

Available strengths

gel 5, 7.5 %
tab 25, 100 mg

Cautions

Methemoglobinemia (avoid in congenital/idiopathic methemoglobinemia; stop if cyanosis)
Hemolysis — G6PD deficiency; avoid with oral dapsone/antimalarials; TMP/SMX may increase risk
Peripheral neuropathy (reported with oral dapsone)
Skin reactions (TEN, EM, etc. — reported with oral dapsone)

Adverse reactions

Application site dryness (1.1%)
Application site pruritus (0.9%)

Pregnancy No human data; systemic absorption low; embryocidal in rats/rabbits only at >400× MRHD exposure.

Lactation No data for topical; oral dapsone enters milk and may cause hemolytic anemia/hyperbilirubinemia, esp. in G6PD-deficient infants.

Cost

Dapsone (ACZONE)

Strength		#/mo	generic $/unit	CostPlus
5 %	gel	per unit		not offered
7.5 %	gel	per unit		not offered

NADAC is a voluntary CMS survey of what retail community pharmacies pay for the drugs they stock. Dapsone is dispensed outside retail pharmacies, so it rarely appears on surveyed invoices.

Generic entry2016

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Self-check

What test precedes dapsone?
G6PD.
Which skin disease can respond to dapsone within days?
Dermatitis herpetiformis.