Betamethasone dipropionate

Betamethasone dipropionate spray can produce reversible hypothalamic-pituitary-adrenal (HPA) axis suppression with the potential for glucocorticosteroid insufficiency. This may occur during or after withdrawal of treatment. Factors that predispose to HPA axis suppression include the use of high-potency corticosteroids, large treatment surface areas, prolonged use, use of occlusive dressings, altered skin barrier, liver failure, and young age.

Evaluation for HPA axis suppression may be done by using the adrenocorticotropic hormone (ACTH) stimulation test.

In a study including 48 evaluable subjects 18 years of age or older with moderate to severe plaque psoriasis, abnormal ACTH stimulation test results suggestive of adrenal suppression were identified in 5 out of 24 (20.8%) subjects after treatment with betamethasone dipropionate spray twice daily for 15 days. No subject (0 out of 24) had abnormal ACTH stimulation test results after treatment with betamethasone dipropionate spray twice daily for 29 days [see Clinical Pharmacology (12.2)].

If HPA axis suppression is documented, gradually withdraw the drug, reduce the frequency of application, or substitute with a less potent corticosteroid. If signs and symptoms of steroid withdrawal occur, supplemental systemic corticosteroids may be required.

Systemic effects of topical corticosteroids may also manifest as Cushing's syndrome, hyperglycemia, and glucosuria. These events are rare and generally occur after prolonged exposure to larger than recommended doses, particularly with high-potency topical corticosteroids.

Minimize the unwanted risks from endocrine effects by mitigating the risk factors favoring increased systemic bioavailability and by using the product as recommended [see Dosage and Administration (2)] .

Pediatric patients may be more susceptible to systemic toxicity due to their larger skin surface to body mass ratios. Use of betamethasone dipropionate spray is not recommended in pediatric patients [see Use in Specific Populations (8.4)].

Use of topical corticosteroids, including betamethasone dipropionate spray, may increase the risk of posterior subcapsular cataracts and glaucoma. Cataracts and glaucoma have been reported postmarketing with the use of topical corticosteroid products, including betamethasone dipropionate [see Adverse Reactions (6.2)] .

Avoid contact of betamethasone dipropionate spray with eyes. Advise patients to report any visual symptoms and consider referral to an ophthalmologist for evaluation.

Allergic contact dermatitis with corticosteroids is usually diagnosed by observing failure to heal rather than noting a clinical exacerbation. Corroborate such an observation with appropriate diagnostic patch testing. If irritation develops, discontinue the topical corticosteroid and institute appropriate therapy.

Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in clinical practice.

In two randomized, multicenter, prospective vehicle-controlled clinical trials, subjects with moderate plaque psoriasis of the body applied betamethasone dipropionate spray or vehicle spray twice daily for 4 weeks. A total of 352 subjects applied betamethasone dipropionate spray and 180 subjects applied vehicle spray.

Adverse reactions that occurred in at least 1% of subjects treated with betamethasone dipropionate spray for up to 28 days are presented in Table 1.

Less common adverse reactions (with occurrence lower than 1% but higher than 0.1%) in subjects treated with betamethasone dipropionate spray were application site reactions including telangiectasia, dermatitis, discoloration, folliculitis and skin rash, in addition to dysgeusia and hyperglycemia. These adverse reactions were not observed in subjects treated with vehicle.

Because adverse reactions are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure.

Postmarketing reports for local adverse reactions to topical corticosteroids have also included striae, irritation, dryness, acneiform eruptions, hypopigmentation, perioral dermatitis, allergic contact dermatitis, secondary infection, hypertrichosis, and miliaria.

Hypersensitivity reactions, consisting of predominantly skin signs and symptoms, e.g., contact dermatitis, pruritus, bullous dermatitis, and erythematous rash have been reported.

Ophthalmic adverse reactions of cataracts, glaucoma, and increased intraocular pressure have been reported with the use of topical corticosteroids, including topical betamethasone products.

Safety and effectiveness of betamethasone dipropionate spray in patients younger than 18 years of age have not been studied; therefore use in pediatric patients is not recommended. Because of a higher ratio of skin surface area to body mass, pediatric patients are at greater risk of systemic toxicity, including HPA axis suppression and adrenal insufficiency, when treated with topical drugs. [see Warnings and Precautions (5.1)]

Rare systemic effects such as Cushing's syndrome, linear growth retardation, delayed weight gain, and intracranial hypertension have been reported in pediatric patients, especially those with prolonged exposure to large doses of high potency topical corticosteroids.

Local adverse reactions including skin atrophy have also been reported with use of topical corticosteroids in pediatric patients.

Clinical studies of betamethasone dipropionate spray did not include sufficient numbers of subjects who were 65 years of age or older to determine whether they respond differently from younger subjects.

Corticosteroids play a role in cellular signaling, immune function, inflammation, and protein regulation; however, the precise mechanism of action of betamethasone dipropionate spray in psoriasis is unknown.

Vasoconstrictor studies performed with betamethasone dipropionate spray in healthy subjects indicate that it is in the mid-range of potency as compared with other topical corticosteroids; however, similar blanching scores do not necessarily imply therapeutic equivalence.

The potential for HPA axis suppression by betamethasone dipropionate spray was evaluated in a study randomizing 52 adult subjects with moderate to severe plaque psoriasis. Betamethasone dipropionate spray was applied twice daily for 15 or 29 days, in subjects with psoriasis involving a mean of 29.0% and 26.5% body surface area at baseline across the 2 treatment duration arms, respectively. Forty-eight (48) subjects were evaluated for HPA axis suppression at the end of treatment. The proportion of subjects demonstrating HPA axis suppression was 20.8% (5 out of 24) in subjects treated with betamethasone dipropionate spray for 15 days. No subjects (0 out of 24) treated with betamethasone dipropionate spray for 29 days had HPA axis suppression. In this study HPA axis suppression was defined as serum cortisol level ≤18 mcg/dL 30-minutes post-cosyntropin stimulation. In the 4 subjects with available follow-up values, all subjects had normal ACTH stimulation tests at follow-up.

The extent of percutaneous absorption of topical corticosteroids is determined by many factors including the vehicle, the integrity of the epidermal barrier, and the use of occlusive dressings. Topical corticosteroids are absorbed through normal intact skin. Inflammation and/or other disease processes in the skin may increase percutaneous absorption.

Plasma concentrations of betamethasone dipropionate, betamethasone-17-propionate, and betamethasone were measured at baseline, and before and after the last dose (1, 3, and 6 hours) in the HPA axis suppression trial in subjects with psoriasis [see Clinical Pharmacology (12.2)] . The majority of subjects had no measurable plasma concentration (<5.00 pg/mL) of betamethasone dipropionate, while the metabolites, betamethasone-17-propionate and betamethasone, were detected in the majority of subjects (Table 2). There was high variability in the data but there was a trend toward higher systemic exposure at Day 15 and lower systemic exposure at Day 29.

Long-term animal studies have not been performed to evaluate the carcinogenic potential of betamethasone dipropionate.

In a 90-day repeat-dose toxicity study in rats, topical administration of betamethasone dipropionate spray formulation at dose concentrations of 0.05% and 0.1% (providing dose levels up to 0.5 mg/kg/day in males and 0.25 mg/kg/day in females) resulted in a toxicity profile consistent with long-term exposure to corticosteroids including reduced body weight gain, adrenal atrophy, and histological changes in bone marrow, thymus and spleen indicative of severe immune suppression. A no observable adverse effect level (NOAEL) could not be determined in this study. Although the clinical relevance of the findings in animals to humans is not clear, sustained glucocorticoid-related immune suppression may increase the risk of infection and possibly the risk of carcinogenesis.

Betamethasone was negative in the bacterial mutagenicity assay ( Salmonella typhimuriumand Escherichia coli), and in the mammalian cell mutagenicity assay (CHO/HGPRT). It was positive in the in vitrohuman lymphocyte chromosome aberration assay, and equivocal in the in vivomouse bone marrow micronucleus assay.

Studies in rabbits, mice, and rats using intramuscular doses up to 1 mg/kg, 33 mg/kg, and 2 mg/kg, respectively, resulted in dose-related increases in fetal resorptions in rabbits and mice.

Betamethasone dipropionate spray, 0.05% is a slightly thickened, white to off-white, non-sterile emulsion supplied in high density polyethylene bottles with a heat induction seal lined polypropylene cap. The drug is supplied in the following volumes:

Store at 20° to 25°C (68° to 77°F)[see USP Controlled Room Temperature].

Each unit is co-packaged with a manual spray pump for installation by the pharmacist prior to dispensing.

1. Remove the spray pump from the wrapper.
2. Remove and discard the cap from the bottle.
3. Keeping the bottle upright, insert the spray pump into the bottle and turn clockwise until it is closed tightly.
4. Dispense the bottle with the spray pump inserted.
5. Include the date dispensed in the space provided on the carton.