Fluocinolone acetonide

BRAND NAMES

1. Synalar (topical cream/ointment/solution) 

2. Derma-Smoothe/FS (fluocinolone acetonide topical oil) 

3. Capex (shampoo for scalp conditions) 

4. Flucort (commonly used brand in some countries, including India) 

5. Flucort-N (combination product with neomycin in some formulations)

MECHANISM OF ACTION

Fluocinolone acetonide is a synthetic corticosteroid (glucocorticoid) that acts by binding to intracellular glucocorticoid receptors in target cells. After binding, the drug–receptor complex moves into the nucleus and regulates gene transcription. This leads to suppression of inflammatory mediators such as prostaglandins, leukotrienes, cytokines, and histamine.

PHARMACOKINETICS

Absorption

Fluocinolone acetonide is absorbed through the skin in variable amounts depending on the formulation, site of application, skin integrity, and use of occlusive dressings. Topical absorption increases in inflamed or damaged skin.

Distribution

After systemic absorption, it binds extensively to plasma proteins and distributes widely into tissues. Systemic exposure is usually low with proper topical use.

Metabolism

It is primarily metabolized in the liver via reduction and conjugation pathways into inactive metabolites.

Elimination

Metabolites are excreted mainly through the urine and bile. Minimal unchanged drug is excreted.

PHARMACODYNAMICS

Fluocinolone acetonide exerts its effects by modulating gene expression through glucocorticoid receptor activation, leading to inhibition of inflammatory gene transcription and increased production of anti-inflammatory proteins such as lipocortin. This results in reduced phospholipase A2 activity, thereby decreasing synthesis of prostaglandins and leukotrienes responsible for inflammation.

ADMINISTRATION

Fluocinolone acetonide is administered topically in the form of creams, ointments, scalp oils, lotions, or shampoos. It is applied in a thin layer to affected areas of the skin, usually once or twice daily, depending on severity and formulation. Occlusive dressings may increase absorption but also increase risk of adverse effects. Prolonged use should be avoided.

DOSAGE AND STRENGTH

Dosage depends on formulation and condition:

1. Cream/Ointment: usually 0.01% to 0.025%, applied thinly 1–2 times daily 

2. Scalp oil/shampoo: applied to affected scalp areas and left for a specified time before washing 

3. Treatment duration: typically short-term (1–2 weeks) for acute flares 

DRUG INTERACTIONS

Clinically significant interactions are rare with topical use. However, concurrent use with other corticosteroids (systemic or topical) may increase the risk of additive systemic corticosteroid effects, especially with prolonged or extensive application.

FOOD INTERACTIONS

No known food interactions exist. Fluocinolone acetonide is used topically and is not affected by dietary intake.

CONTRAINDICATIONS

1. Hypersensitivity to fluocinolone acetonide or other corticosteroids 

2. Untreated bacterial, fungal, or viral skin infections (unless appropriately treated) 

3. Use in rosacea or perioral dermatitis (may worsen condition) 

4. Avoid prolonged use on large skin areas, especially in children.

SIDE EFFECTS 

1. Burning or irritation at application site 

2. Dry skin 

3. Stretch marks (striae) with prolonged use 

4. Acne or folliculitis 

5. Hypopigmentation  

6. Increased hair growth at application site.

OVER DOSAGE

Overdosage of fluocinolone acetonide is uncommon when used topically, but it can occur with excessive application, prolonged use, use over large body surface areas, or application under occlusive dressings, which significantly increases systemic absorption.

TOXICITY

Excessive or prolonged use of fluocinolone acetonide can lead to systemic corticosteroid toxicity, especially when applied over large areas or under occlusion. This may include HPA axis suppression, Cushing’s syndrome features, hyperglycemia, and adrenal insufficiency.