Crotamiton (Monograph)

Brand name: Eurax
Drug class: Scabicides and Pediculicides
VA class: AP900
Chemical name: N-ethyl-N-(o-methylphenyl)-2-butenamide
CAS number: 483-63-6

Introduction

Scabicide and antipruritic agent.

Uses for Crotamiton

Scabies

Alternative for topical treatment of scabies in adults. AAP, CDC, and others usually recommend topical permethrin 5% as scabicide of choice; oral ivermectin also recommended by CDC as a drug of choice.

May be less effective than topical permethrin. Treatment failures have occurred; several applications of the drug may be necessary.

Other scabicides usually recommended for treatment of severe or crusted (Norwegian) scabies^{† [off-label]}. Aggressive treatment with a multiple-dose oral ivermectin regimen or concomitant use of oral ivermectin and a topical scabicide may be necessary. HIV-infected and other immunocompromised patients are at increased risk of developing Norwegian scabies; CDC recommends that such patients be managed in consultation with an expert.

HIV-infected individuals with uncomplicated scabies should receive the same treatment regimens as those without HIV infection.

Pediculosis

Has been used for treatment of pediculosis capitis^{† [off-label]} (head lice infestation). Safety and efficacy not established.

Treatment of pediculosis corporis^{† [off-label]} (body lice infestation). One of several options recommended for treatment of pediculosis corporis in the adjunctive treatment of epidemic (louse-borne) typhus. The causative agent of epidemic typhus (Rickettsia prowazekii) is transmitted person-to-person by Pediculus humanus corporis and thorough delousing (especially among exposed contacts of individuals with typhus) is recommended in epidemic situations.

Pruritus

Symptomatic treatment of pruritus.

Crotamiton Dosage and Administration

General

Measures to Avoid Reinfestation and Transmission

To avoid reinfestation or transmission of scabies, clothing and bed linen that may have been contaminated by the infested individual during the 3 days prior to treatment should be decontaminated (machine-washed in hot water and dried in a hot dryer or dry-cleaned).
Items that cannot be laundered or dry-cleaned should be removed from body contact for ≥72 hours.
Fumigation of living areas is not necessary and is not recommended.

Administration

Topical Administration

Apply topically to skin as 10% cream or lotion.

Do not apply to face, eyes, mouth, urethral meatus, or mucous membranes. For external use only; do not administer orally or intravaginally.

Shake lotion before using.

Scabies

Before applying crotamiton for the treatment of scabies, the patient should bathe or shower with soap and water, taking care to scrub and remove scaling or crusted detritus, then towel dry.

Apply thin layer of the cream or lotion uniformly and massage thoroughly into all skin surfaces below the chin (particularly all creases and folds) including the entire trunk and extremities from the neck to the toes (including the soles of the feet). Trim fingernails short and apply the cream or lotion underneath the fingernails with a toothbrush; wrap the toothbrush in paper and properly discard to prevent potential oral crotamiton exposure and toxicity.

Remove the cream or lotion 48 hours after the last application by bathing.

Sexual contacts of patients receiving treatment for scabies and other individuals (household, family) who have had close personal contact with the patient within the previous month should be examined and treated.

The CDC recommends that scabies epidemics in institutional settings (e.g., nursing homes, hospitals, residential facilities and communities) be managed in consultation with an expert. The entire population at risk should be treated during institutional outbreaks.

Pruritus does not indicate treatment failure and is not usually considered an indication for retreatment; such pruritus results from a hypersensitivity reaction of the host to the mite and may persist for several weeks despite successful treatment. Oral antihistamines and/or topical corticosteroids may be used to help relieve pruritus. Topical or oral anti-infectives are indicated for treatment of secondary bacterial infections of excoriated skin lesions.

Dosage

Pediatric Patients

Scabies† [off-label]

Topical

Cream or lotion: Apply a thin, uniform layer and massage thoroughly into all skin surfaces below the chin (particularly to all creases and folds) including the entire trunk and extremities from the neck to the toes (including the soles of the feet and underneath the fingernails). A proportionately smaller amount is applied in children compared to the amount applied in adults (30 g usually is sufficient in adults). Wash off by bathing 48 hours after the last application.

The manufacturer recommends a second application 24 hours after the first treatment. Frequent treatment failures reported; some clinicians suggest several applications are necessary to cure scabies. CDC recommends that patients who do not respond to crotamiton should be retreated with an alternative regimen.

Pediculosis† [off-label]

Pediculosis Capitis† (Head Lice Infestation)

Topical

Lotion has been applied to the scalp and left on for 24 hours before being washed off.

Adults

Scabies

Topical

Cream or lotion: Apply a thin, uniform layer and massage thoroughly into all skin surfaces below the chin (particularly to all creases and folds) including the entire trunk and extremities from the neck to the toes (including the soles of the feet and underneath the fingernails). Usually, 30 g of the cream is sufficient for one application. Wash off by bathing 48 hours after the last application.

The manufacturer recommends a second application 24 hours after the first treatment. Frequent treatment failures reported; some clinicians suggest several applications are necessary to cure scabies. CDC recommends retreating patients who do not respond to crotamiton with an alternative regimen.

Pediculosis†

Pediculosis Capitis† (Head Lice Infestation)

Topical

Lotion has been applied to the scalp and left on for 24 hours before being washed off.

Pruritus

Topical

Cream or lotion: Massage gently into affected areas until completely absorbed; repeat application as needed.

Cautions for Crotamiton

Contraindications

Known sensitivity or allergy to crotamiton or known primary irritation response to other topical medications.

Warnings/Precautions

Sensitivity Reactions

Dermatologic and Sensitivity Reactions

If severe irritation or a sensitivity reaction occurs following topical application, discontinue and initiate appropriate therapy.

General Precautions

Administration Precautions

Avoid contact with the eyes or mouth since irritation may occur.

Avoid contact with mucous membranes, the vagina, and urethral meatus.

Do not apply to acutely inflamed skin or denuded or weeping skin surfaces until acute inflammation has resolved.

Specific Populations

Pregnancy

Category C.

Lactation

Information regarding distribution into milk not available.

Pediatric Use

Safety and efficacy not established in children.

Geriatric Use

Insufficient experience in controlled clinical studies in patients ≥65 years of age to determine whether geriatric patients respond differently than younger adults. Other clinical experience has not revealed age-related differences in response; however, greater sensitivity of some geriatric individuals cannot be ruled out.

Common Adverse Effects

Primary irritation reactions (e.g., dermatitis, pruritus, rash), allergic sensitivity reactions.

Crotamiton Pharmacokinetics

Absorption

Bioavailability

Absorbed systemically following topical application to skin.

Elimination

Elimination Route

In a study in healthy adults using radiolabeled crotamiton 10% lotion applied topically twice daily (0.229 mL applied on an area of the forearm 229 cm²), 4.8–8.8% of the dose (measured as radioactivity) was eliminated in urine.

Half-life

Following topical application to skin, absorption half-life is 2.7 hours and rate of elimination is 30.9 hours.

Stability

Storage

Topical

Cream or Lotion

Room temperature.

Actions and Spectrum

The mechanisms of crotamiton’s scabicidal, pediculicidal, and antipruritic effects not known.
Active against Sarcoptes scabiei (mite that causes scabies), Pediculus humanus var. capitis (head louse), and Pediculus humanus var. corporis (body louse).
Resistance to crotamiton has not been conclusively demonstrated in S. scabiei.

Advice to Patients

Importance of using only as directed.
Advise patients regarding personal protective measures to avoid reinfestation or transmission of scabies.
Importance of taking a routine bath or shower prior to application, applying the cream or lotion as directed, and removing the drug by bathing 48 hours after the last application.
Importance of informing clinicians of existing or contemplated concomitant therapy, including prescription or OTC drugs, dietary supplements, herbal supplements, or any other skin product.
Importance of women informing clinicians if they are or plan to become pregnant or plan to breast-feed.
Importance of informing patients of other important precautionary information. (See Cautions.)

Preparations

Excipients in commercially available drug preparations may have clinically important effects in some individuals; consult specific product labeling for details.

Please refer to the ASHP Drug Shortages Resource Center for information on shortages of one or more of these preparations.