HSA Reclassified Drug | Exemptions For Supply of Azelaic Acid Without Prescription


Eligible Active Ingredient: Azelaic Acid. As a topical preparation containing 20% w/w
With Effective From: 1-Jul-2012
Indication Permitted: Mild to Moderate Acne Vulgaris
Maximum Daily Dose: Apply to the affected area twice daily
Maximum Supply per Transaction: 30 grams
Minimum Age of User: 12 years
Patient Information Leaflet from HSA/PSS: Download PIL (Link to HSA website)

Mechanism of Action of Azelaic Acid

The exact mechanism of action of azelaic acid is not known. It is thought that azelaic acid manifests its antibacterial effects by inhibiting the synthesis of cellular protein in anaerobic and aerobic bacteria, especially Staphylococcus epidermidis and Propionibacterium acnes. In aerobic bacteria, azelaic acid reversibly inhibits several oxidoreductive enzymes including tyrosinase, mitochondrial enzymes of the respiratory chain, thioredoxin reductase, 5-alpha-reductase, and DNA polymerases. In anaerobic bacteria, azelaic acid impedes glycolysis. Along with these actions, azelaic acid also improves acne vulgaris by normalizing the keratin process and decreasing microcomedo formation. Azelaic acid may be effective against both inflamed and noninflamed lesions. Specifically, azelaic acid reduces the thickness of the stratum corneum, shrinks keratohyalin granules by reducing the amount and distribution of filaggrin (a component of keratohyalin) in epidermal layers, and lowers the number of keratohyalin granules.

Additional Information of Azelaic Acid

Pharmacology Class: Anti-Acne Preparations For Topical Use
Therapeutic Class: Anti-Acne Preparations
Chemical Class: Other Anti-Acne Preparations For Topical Use
Synonyms: 1,7-Dicarboxyheptane | 1,7-Heptanedicarboxylic acid | 1,9-Nonanedioic acid | Acide azélaïque | Ácido azelaico | Acidum acelaicum | Acidum azelaicum | Anchoic acid | Azelaic acid | Azelainsaeure | Azelainsäure | Lepargylic acid | N-Nonanedioic acid | Nonandisaeure | Nonandisäure | Nonanedioic acid | Skinoren

Show All HSA-registered therapeutic products granted exemption to supply without prescription


  1. Health Science Authority of Singapore – Reclassified POM
  2. Drugbank

HSA-Registered Products Containing Azelaic Acid As a topical preparation containing 20% w/w

wpDataTable with provided ID not found!

This list is not exhaustive. HSA collaborates with Pharmaceurical Society of Singapore (PSS) to review the appropriate use of therapeutic products in the community from time to time. Hence, HSA may enable the supply of a Prescription Only Medicine (POM) by pharmacists without a prescription, upon review that the product can be used in a safe and effective manner under the supervision of a pharmacist. This can be effected through legislative mechanisms in the absence of an application made by the product registrant to reclassify the therapeutic product, subject to to conditions including indication, strength, maximum daily dose, maximum supply quantity, and age restriction.