The Primary Ingredients of Magnesium Sulphate Paste
Magnesium sulphate paste, often referred to as 'drawing paste,' is a topical medication with a specific combination of ingredients designed to treat superficial skin infections and draw out foreign bodies. The composition, as outlined in product patient leaflets and descriptions, is centered around three main components.
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Dried Magnesium Sulphate (47.76% w/w): This is the key active ingredient and is essentially Epsom salt in a dehydrated, powdered form. Magnesium sulphate works through the principle of osmosis. When applied to the skin, its high concentration draws out moisture and exudate, such as pus, from the affected area. This drawing action helps to bring boils, splinters, or other minor infections to a head, assisting the body's natural healing process.
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Glycerol (E422): This ingredient serves as the paste's base or vehicle. Glycerol is a humectant, meaning it attracts and retains moisture. It is what gives the ointment its thick, paste-like consistency, allowing the dried magnesium sulphate to remain in contact with the skin and exert its osmotic effect. Additionally, it provides a soothing and moisturizing effect on the skin, counteracting the drying action of the magnesium sulphate.
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Phenol (0.49% w/w): Included in a low concentration, phenol contributes to the paste's properties with its mild antiseptic and antimicrobial actions. It helps to disinfect the skin's surface and prevent the spread of bacteria, though it is not a substitute for proper cleaning of the wound. Its presence in the paste complements the drawing action by creating a less hospitable environment for surface bacteria.
The Mechanism of Action: How the Paste Works
The combined effect of the ingredients is what makes magnesium sulphate paste an effective topical remedy. The interaction between the active compounds and the skin is primarily driven by osmotic pressure and surface disinfection.
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Osmosis and Fluid Dynamics: The high concentration of dried magnesium sulphate creates a powerful osmotic gradient. In simple terms, this is the movement of water from an area of low solute concentration to an area of high solute concentration. When applied to an infected area, this gradient draws excess fluid, including pus and toxins, out of the skin and into the paste. This helps to reduce swelling and clear the infection.
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Antiseptic Protection: While the osmotic effect is doing the heavy lifting, the phenol acts as a first line of defense against surface bacteria. This dual-action approach—drawing out impurities while also disinfecting—provides a comprehensive topical treatment for minor issues.
Applications and Best Practices
This drawing ointment is commonly used for a variety of localized skin issues.
- Boils and Carbuncles: The paste helps to draw out the pus and bring the infection to a head, aiding in drainage and healing.
- Splinters and Thorns: For small, non-metallic splinters lodged just under the skin's surface, the drawing action can help to ease them out.
- Inflamed Spots and Ingrown Hairs: It can be applied to inflamed spots or ingrown hairs that have formed a pustule to help draw out the contents.
To apply, stir the paste well, spread a liberal amount onto the affected, unbroken skin, and cover it with a breathable dressing. Do not apply the paste to open or broken skin. The application can be repeated, typically twice a day, until the issue resolves.
Comparison Table: Magnesium Sulphate Paste vs. Epsom Salt Baths
While both magnesium sulphate paste and Epsom salt baths contain the same mineral, their form, concentration, and application differ significantly.
| Feature | Magnesium Sulphate Paste | Epsom Salt Bath |
|---|---|---|
| Form | A thick, semi-solid paste containing dried magnesium sulphate, glycerol, and phenol. | Crystalline salt granules (hydrated magnesium sulphate) dissolved in water. |
| Concentration | High, localized concentration applied directly to the affected area. | Diffused, lower concentration spread throughout bathwater. |
| Primary Action | Creates an intense osmotic gradient to draw out pus, fluid, and minor foreign objects. | Offers a calming, relaxing, and soothing effect on muscles and skin. Absorption through the skin is unproven. |
| Targeted Use | Localized skin issues like boils, carbuncles, and splinters. | General muscle aches, relaxation, and soothing minor sprains and bruises. |
| Ingredients | Dried magnesium sulphate, glycerol, and phenol. | Magnesium sulphate heptahydrate (Epsom salt). |
| Contraindications | Not for use on broken skin, in case of allergies, or for deep infections. | Should not be used by those with certain health conditions or taken orally long-term. |
Contraindications and Important Safety Information
While a common and generally safe remedy for minor topical issues, magnesium sulphate paste is not suitable for everyone or every condition. It is important to read the patient information leaflet before use.
- Broken Skin: The paste should never be applied to open wounds or broken skin, as this can cause irritation.
- Allergies: If you have a known hypersensitivity to magnesium sulphate, phenol, or any other ingredients, you should not use the product.
- Deep or Worsening Infections: The paste is for superficial infections only. If a skin condition does not improve or worsens, or if the area is warm to the touch and severely inflamed, you should seek medical advice. Some abscesses require antibiotics.
- Breastfeeding Mothers: Do not apply the paste to the breasts if breastfeeding.
Conclusion
Magnesium sulphate paste is a traditional and effective drawing ointment for minor skin conditions. Its power lies in the combined action of its core ingredients: the osmotic drawing power of dried magnesium sulphate, the emollient and adhesive properties of glycerol, and the mild antiseptic qualities of phenol. By creating an osmotic gradient, the paste draws out impurities, helping to clear infections like boils and splinters. It is a targeted solution for localized issues, differing significantly in function and concentration from the Epsom salts used in baths. When used correctly and on intact skin, it is a useful item to have in a first-aid kit, but users must always be mindful of contraindications and seek medical advice for more serious or persistent infections. For further reading on medicinal products, you can visit the electronic medicines compendium (https://www.medicines.org.uk/emc/product/8327/pil).
Further Reading
For more detailed information, patient information leaflets (PILs) for specific products, like the Boots Magnesium Sulfate Paste B.P., provide comprehensive details on ingredients, usage, and warnings.
How to Buy
Magnesium sulphate paste is available for purchase at most pharmacies, and does not require a prescription. Always follow the product’s specific instructions.
