Understanding the Core Distinction: Brand Name vs. Active Ingredient
When discussing topical antibiotics for skin infections, the names Fucidin® and fusidic acid are often used interchangeably, but they refer to different things. The primary difference is that fusidic acid is the active pharmaceutical ingredient—the chemical compound that provides the therapeutic effect [1.2.5]. Fucidin®, on the other hand, is one of the most common brand names under which fusidic acid is sold and manufactured by LEO Pharma [1.2.4, 1.2.5].
Think of it like this: fusidic acid is the specific type of soldier fighting the bacteria, and Fucidin cream is the vehicle that delivers the soldier to the battlefield (your skin). The cream itself contains fusidic acid at a 2% concentration, along with other inactive ingredients like cetyl alcohol, glycerol, and liquid paraffin that create the cream's consistency and help with application [1.2.5].
What is Fusidic Acid?
Fusidic acid is a steroidal antibiotic derived from the fungus Fusidium coccineum [1.6.1, 1.6.4]. It has a narrow spectrum of activity, meaning it is primarily effective against specific types of bacteria, particularly Gram-positive bacteria like Staphylococcus aureus, which is a frequent cause of skin infections [1.6.2, 1.9.2].
Mechanism of Action Fusidic acid works by inhibiting protein synthesis in bacteria [1.6.2]. It targets and prevents the turnover of a component called elongation factor G (EF-G) from the ribosome. This action effectively halts the bacteria's ability to produce essential proteins needed for growth and replication [1.6.1, 1.6.6]. By stopping the bacteria from multiplying, fusidic acid allows the body's immune system to eliminate the remaining bacteria and clear the infection [1.2.1, 1.2.5]. It is considered bacteriostatic, meaning it stops bacteria from reproducing rather than killing them outright [1.2.1].
What is Fucidin Cream?
Fucidin cream is a prescription-only topical preparation containing 2% fusidic acid [1.2.5]. It is formulated to be applied directly to the skin to treat localized bacterial infections [1.2.5]. Besides the cream, fusidic acid is also available in other formulations:
- Ointment (Fucidin® Ointment): This formulation contains sodium fusidate, a salt of fusidic acid, and is greasier than the cream [1.2.1, 1.4.3]. It's often used for smaller areas of skin or on dry, scaly lesions.
- Eye Drops (Fucithalmic®): A specific formulation designed to treat bacterial eye infections [1.4.4, 1.8.5].
There are also combination products available that include fusidic acid along with a corticosteroid to treat infected and inflamed skin conditions:
- Fucidin® H: Combines fusidic acid (2%) with hydrocortisone (1%), a mild steroid. It's used for conditions like infected eczema or dermatitis where there is both a bacterial infection and inflammation (redness, swelling, itching) [1.2.3, 1.7.4].
- Fucibet®: Combines fusidic acid with betamethasone, which is a more potent steroid than hydrocortisone, for more severe inflammation [1.2.5, 1.4.3].
Comparison Table: Fucidin vs. Fusidic Acid
| Feature | Fusidic Acid | Fucidin Cream |
|---|---|---|
| Identity | Active Pharmaceutical Ingredient (API) | Branded medicinal product [1.2.4, 1.2.5] |
| Function | The chemical substance that inhibits bacterial growth | The delivery vehicle for the active ingredient [1.2.5] |
| Composition | A single chemical compound with a steroidal structure [1.6.2] | 2% fusidic acid plus inactive ingredients (e.g., paraffin, cetyl alcohol) [1.2.5] |
| Form | A powder in its raw state; used in various formulations | A semi-solid topical cream [1.2.5] |
| Availability | Available under many brand names (Fucidin®, Fucithalmic®) and as a generic | A specific brand name product [1.4.2, 1.4.3] |
Common Uses and Application
Fusidic acid preparations like Fucidin cream are prescribed to treat a range of bacterial skin infections, including:
- Impetigo: A contagious skin infection that causes sores and blisters [1.2.1, 1.2.5].
- Infected Eczema and Dermatitis: When existing inflammatory skin conditions become secondarily infected with bacteria [1.7.2, 1.7.4].
- Infected Cuts and Grazes: To prevent or treat infection in minor skin wounds [1.2.1].
- Folliculitis: Inflammation of hair follicles caused by a bacterial infection.
To use the cream, a thin layer is typically applied to the clean, dry, affected area three to four times a day [1.8.4]. Treatment usually lasts for one to two weeks, and it is crucial to complete the full course as prescribed by a doctor to prevent the infection from returning and to minimize the risk of developing antibiotic resistance [1.2.5, 1.5.4].
Potential Side Effects and Precautions
While generally well-tolerated, Fucidin cream can cause side effects, though they are uncommon. The most frequent side effects are local to the application site and may include [1.2.5, 1.5.3, 1.5.4]:
- Itching, burning, or stinging sensation
- Skin redness or irritation
- Dry skin or rash
Serious allergic reactions are rare but require immediate medical attention [1.5.2]. It is important not to use the cream for longer than prescribed, as prolonged use can increase the risk of side effects and lead to antibiotic resistance [1.2.5, 1.5.4]. Fucidin cream should not be used for fungal or viral skin infections like athlete's foot or cold sores, as it is not effective against them [1.7.3].
Conclusion
In summary, the difference between fusidic acid and Fucidin cream is that one is the active drug and the other is the finished product. Fusidic acid is the antibiotic that fights the infection, while Fucidin is the brand name of the cream that carries the antibiotic. Recognizing this distinction helps in understanding that while Fucidin is a specific product, the antibacterial action comes from its core component, fusidic acid, which is also available in other formulations and under other brand names to treat a variety of bacterial infections.
For more information on fusidic acid, you can visit the NHS page on the medication.
