PROCTOFOAM HC

PROCTOFOAM HC- pramoxine hydrochloride and hydrocortisone acetate aerosol, foam
Meda Pharmaceuticals Inc.

DESCRIPTION

Proctofoam^® HC (hydrocortisone acetate 1% and pramoxine hydrochloride 1%) is a topical aerosol foam for anal use containing hydrocortisone acetate 1% and pramoxine hydrochloride 1% in a hydrophilic base containing cetyl alcohol, emulsifying wax, methylparaben, poly-oxyethylene-10-stearyl ether, propylene glycol, propylparaben, purified water, trolamine and inert propellants: isobutane and propane.

Proctofoam^® HC contains a synthetic corticosteroid used as an anti-inflammatory/antipruritic agent and a local anesthetic.

Hydrocortisone acetate

Molecular weight: 404.50. Solubility of hydrocortisone acetate in water: 1 mg/100 mL.

Chemical name: pregn-4-ene-3,20-dione, 21-(acetyloxy)-11,17-dihydroxy-,(11β)-.

Pramoxine hydrochloride

Molecular weight: 329.86. Pramoxine hydrochloride is freely soluble in water. Chemical name: morpholine, 4-[3-(4-butoxyphenoxy) propyl]-, hydrochloride.

CLINICAL PHARMACOLOGY

Topical corticosteroids share anti-inflammatory, antipruritic and vasoconstrictive actions.

The mechanism of anti-inflammatory activity of the topical corticosteroids is unclear. Various laboratory methods, including vasoconstrictor assays, are used to compare and predict potencies and/or clinical efficacies of the topical corticosteroids. There is some evidence to suggest that a recognizable correlation exists between vasoconstrictor potency and therapeutic efficacy in man.

Pramoxine hydrochloride is a surface or local anesthetic which is not chemically related to the “caine” types of local anesthetics. Its unique chemical structure is likely to minimize the danger of cross-sensitivity reactions in patients allergic to other local anesthetics.

Pharmacokinetics

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 can be absorbed through normal intact skin. Inflammation and/or other disease processes in the skin increase the percutaneous absorption of topical corticosteroids. Occlusive dressings substantially increase the percutaneous absorption of topical corticosteroids. Thus, occlusive dressings may be a valuable therapeutic adjunct for treatment of resistant dermatoses. (See DOSAGE AND ADMINISTRATION.)

Once absorbed through the skin, topical corticosteroids are handled through pharmacokinetic pathways similar to systemically administered corticosteroids. Corticosteroids are bound to plasma proteins in varying degrees. Corticosteroids are metabolized primarily in the liver and are then excreted by the kidneys. Some of the topical corticosteroids and their metabolites are also excreted into the bile.

INDICATIONS AND USAGE

Proctofoam^® HC is indicated for the relief of the inflammatory and pruritic manifestations of corticosteroid-responsive dermatoses of the anal region.

CONTRAINDICATIONS

Topical corticosteroid products are contraindicated in those patients with a history of hypersensitivity to any of the components of the preparation.

WARNINGS

Do not insert any part of the aerosol container directly into the anus. Avoid contact with the eyes. Contents of the container are under pressure. Do not burn or puncture the aerosol container. Do not store at temperatures above 120°F (49°C). If there is no evidence of clinical improvement within two or three weeks after starting Proctofoam^® HC therapy, or if the patient’s condition worsens, discontinue the drug. Keep this and all medicines out of the reach of children.

PRECAUTIONS

General

Systemic absorption of topical corticosteroids has produced reversible hypothalamic-pituitary-adrenal (HPA) axis suppression, manifestations of Cushing’s syndrome, hyperglycemia, and glucosuria in some patients.

Conditions which augment systemic absorption include the application of the more potent steroids, use over large surface areas, prolonged use, and the addition of occlusive dressings. Therefore, patients receiving a large dose of a potent topical steroid applied to a large surface area or under an occlusive dressing should be evaluated periodically for evidence of HPA axis suppression by using the urinary free cortisol and ACTH stimulation tests. If HPA axis suppression is noted, an attempt should be made to withdraw the drug, to reduce the frequency of application or to substitute a less potent steroid.

Recovery of HPA axis function is generally prompt and complete upon discontinuation of the drug. Infrequently, signs and symptoms of steroid withdrawal may occur, requiring supplemental systemic corticosteroids. Pediatric patients may absorb proportionally larger amounts of topical corticosteroids and thus be more susceptible to systemic toxicity. (see PRECAUTIONS: Pediatric Use.)

If irritation develops, topical corticosteroids should be discontinued and appropriate therapy instituted.

In the presence of dermatological infections, the use of an appropriate antifungal or antibacterial agent should be instituted. If a favorable response does not occur promptly, the corticosteroid should be discontinued until the infection has been adequately controlled.

Information for the Patient

Patients using topical corticosteroids should receive the following information and instructions:

1.

This medication is to be used as directed by the physician. It is for anal or perianal use only. Avoid contact with eyes.

2.

Be advised not to use this medication for any disorder other than for which it has been prescribed.

3.

Report any signs of adverse reactions.

Laboratory Tests

The following tests may be helpful in evaluating the HPA axis suppression:

Urinary free cortisol test

ACTH stimulation test

Carcinogenesis, Mutagenesis, Impairment of Fertility

Long-term animal studies have not been performed to evaluate the carcinogenic potential or the effect on fertility of topical corticosteroids.

Studies to determine mutagenicity with prednisolone and hydrocortisone have revealed negative results.

Pregnancy

Teratogenic Effects

Corticosteroids are generally teratogenic in laboratory animals when administered systemically at relatively low dosage levels. The more potent corticosteroids have been shown to be teratogenic after dermal application in laboratory animals. There are no adequate, well-controlled studies of teratogenic effects from topically applied corticosteroids in pregnant women. Therefore, topical corticosteroids should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus. Drugs of this class should not be used extensively on pregnant patients, in large amounts, or for prolonged periods of time.

Nursing Mothers

It is not known whether topical administration of corticosteroids could result in sufficient systemic absorption to produce detectable quantities in breast milk. Systemically administered corticosteroids are secreted into breast milk in quantities not likely to have a deleterious effect on the infant. Nevertheless, caution should be exercised when topical corticosteroids are administered to a nursing woman.

Pediatric Use

Pediatric patients may demonstrate greater susceptibility to topical corticosteroid-induced HPA axis suppression and Cushing’s syndrome than mature patients because of a larger skin surface area to body weight ratio.

Hypothalamic-pituitary-adrenal (HPA) axis suppression, Cushing’s syndrome, and intracranial hypertension have been reported in pediatric patients receiving topical corticosteroids. Manifestations of adrenal suppression in pediatric patients include linear growth retardation, delayed weight gain, low plasma cortisol levels, and absence of response to ACTH stimulation. Manifestations of intracranial hypertension include bulging fontanelles, headaches, and bilateral papilledema.

Administration of topical corticosteroids to pediatric patients should be limited to the least amount compatible with an effective therapeutic regimen. Chronic corticosteroid therapy may interfere with the growth and development of pediatric patients.