Urea

AHFS Class: Keratolytic Agents (84:28)

VA Class: DE350
ATC Class: D02AE01

Carbamide

View the associated Essentials monograph.

Introduction

Urea, at concentrations of 10–30%, promotes hydration of keratin and mild keratolysis in dry and hyperkeratotic skin.

Chemistry and Stability

Chemistry

Urea, the diamide of carbonic acid, occurs as colorless to white, prismatic crystals or as a white, crystalline powder. The drug is freely soluble in water and soluble in alcohol and has a cooling, saline, unpleasant taste; it is practically odorless but may gradually develop a slight ammoniacal odor on long standing. An endothermic reaction occurs on dissolution of urea; to shorten dissolution time, the diluent may be warmed in a water bath to a temperature of 60°C before mixing with urea.

Stability

Upon standing, heating, or exposure to acids or alkalies, urea is hydrolyzed to ammonia and carbon dioxide. Solutions of urea are unstable and cannot be sterilized by heat. Urea should be stored in well-closed containers.

Uses

Urea is used topically in the treatment of dry skin. At concentrations of 10–30%, urea promotes hydration of keratin and mild keratolysis in dry and hyperkeratotic skin. The drug increases the uptake of water by the stratum corneum, giving it a high water-binding capacity. Topically applied urea may also have an antipruritic effect. At high concentrations (e.g., 40%), urea is a protein denaturant.

For use of urea as a diuretic or oxytocic, see 40:28.12 or 76:00, respectively.

Cautions

Adverse Effects

When used in appropriate dosage, topically applied urea preparations have a low order of toxicity. Transient stinging may occur, especially when urea preparations are applied to the face or broken or inflamed skin. Local irritation may also occur following topical application of urea.

Precautions and Contraindications

Topical preparations containing urea are intended for external use only. Topical urea preparations should be applied with caution to the face or broken or inflamed skin. Urea should not be used near the eyes.

Some commercially available topical formulations of urea contain sulfites that may cause allergic-type reactions, including anaphylaxis and life-threatening or less severe asthmatic episodes, in certain susceptible individuals. The overall prevalence of sulfite sensitivity in the general population is unknown but probably low; such sensitivity appears to occur more frequently in asthmatic than in nonasthmatic individuals. Topical urea preparations should be discontinued if local irritation or rash occurs during use.

Dosage and Administration

Urea is applied topically as a cream or lotion. The moisturizing effect of urea may be enhanced by applying the preparation to the skin while it is still moist after washing or bathing. Urea is applied topically to the affected area 1–3 times daily or as directed by a physician.

Preparations

Urea

Routes	Forms	Strengths	Brand Names	Manufacturer
Powder*
Crystals*
Topical	Cream	10%	Aqua Care® (with benzyl alcohol)	Numark
			Nutraplus®	Healthpoint
		20%	Carmol® (with propylene glycol)	Doak
			Ureacin® (with parabens)	Pedinol
		22%	Gordon’s® Urea	Gordon
		30%	Rea-Lo®	Med-Derm
		40%	Gordon’s® Urea	Gordon
	Lotion	10%	Aqua Care® (with benzyl alcohol)	Numark
			Carmol®	Doak
			Nutraplus®	Healthpoint
			Ureacin® (with parabens)	Pedinol
		15%	Rea-Lo®	Med-Derm
		25%	Ultra Mide®	Teva

* available by nonproprietary name

Urea Combinations

Routes	Forms	Strengths	Brand Names	Manufacturer
Topical	Cream	10% with Hydrocortisone Acetate 1%	Carmol® HC (with propylene glycol and sodium metabisulfite)	Doak

Comparative Pricing

This pricing information is subject to change at the sole discretion of DS Pharmacy. For the most current and up-to-date pricing information, please visit www.drugstore.com.

Carmol 10% SHAM (PHARMADERM): 240/$23.52 or 720/$70.56

Carmol 10 10% LOTN (DOAK DERMATOLOGICS): 177/$23.99 or 531/$49.97

Carmol 20 20% Cream (DOAK DERMATOLOGICS): 85/$21.99 or 170/$32.98

Carmol 40 40% Cream (DOAK DERMATOLOGICS): 198/$186.98 or 595/$540.09

Carmol 40 40% Cream (DOAK DERMATOLOGICS): 28/$72.52 or 85/$196.11

Carmol 40 40% Cream (DOAK DERMATOLOGICS): 85/$103.64 or 255/$292.13

Carmol 40 40% Gel (PHARMADERM): 15/$198.54 or 45/$558.41

Cerovel 40% LOTN (HAWTHORN PHARMACEUTICALS): 325/$89.99 or 975/$249.99

Hydro 40 40% Foam (QUINNOVA): 70/$99.34 or 210/$280.75

Keralac 35% LOTN (DOAK DERMATOLOGICS): 325/$204.82 or 975/$604.31

Keralac 50% Cream (DOAK DERMATOLOGICS): 142/$120.39 or 426/$328.32

Keralac 50% Cream (DOAK DERMATOLOGICS): 255/$167.41 or 765/$475.75

Keralac 50% Gel (DOAK DERMATOLOGICS): 18/$178.19 or 54/$516.97

Keralac 50% Ointment (DOAK DERMATOLOGICS): 45/$87.02 or 135/$253.1

Urea 40% Cream (HI-TECH): 198/$66.23 or 397/$132.47

Urea 40% Cream (HI-TECH): 28/$24.99 or 85/$74.97

Urea 40% Cream (HI-TECH): 85/$34.99 or 170/$64.98

Urea 40% LOTN (HI-TECH): 236/$74.98 or 473/$144

Urea 50% Ointment (RIVER'S EDGE PHARMACEUTICALS): 45/$51.99 or 135/$145.98

Urealac 35% LOTN (HI-TECH): 325/$85.09 or 975/$249.99

Vanamide 40% Cream (DERMIK): 85/$60.87 or 255/$167.82

Zoderm 4.5-10% Cream (PHARMADERM): 125/$155.58 or 375/$447.34

Zoderm 4.5-10% Gel (PHARMADERM): 125/$155.95 or 375/$460.24

Selected Revisions March 2006, © Copyright, January 1959, American Society of Health-System Pharmacists, Inc. 7272 Wisconsin Avenue, Bethesda, MD 20814.