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Benzyl Benzoate (Topical)


VA CLASSIFICATION
Primary: AP300
Secondary: AP900
{11}
Commonly used brand name(s): Ascabiol.

Note: For a listing of dosage forms and brand names by country availability, see Dosage Forms section(s).

*Not commercially available in the U.S.

Not commercially available in Canada.



Category:


Pediculicide—

scabicide{02}{03}{04} {05}{13}

Indications

Note: Because benzyl benzoate is not commercially available in the U.S. or Canada, the bracketed information and the use of the superscript 1 in this monograph reflect the lack of labeled (approved) indications for this medication.

Accepted

[Pediculosis (treatment)]1—Benzyl benzoate is used in the topical treatment of pediculosis caused by Pediculus capitis (head louse) and Phthirus pubis (pubic or crab louse). {01} {02} {03} {04} {05} {08} {13}

[Scabies (treatment)]1—Benzyl benzoate is used in the topical treatment of scabies caused by the Sarcoptes scabiei mite. {01} {02} {03} {04} {05} {06} {08} {13} {14}

1 Not included in Canadian product labeling.



Pharmacology/Pharmacokinetics

Physicochemical characteristics:
Source—
    Prepared synthetically by the esterification of benzoic acid with benzyl alcohol. {08}
Molecular weight—
    212.2 {01}

Mechanism of action/Effect:

Unknown, {01} {03} {08} but in view of the medication's effects on vertebrates, it is thought that benzyl benzoate may act on the nervous system of the parasite, resulting in its death. {01}

In vitro, benzyl benzoate has been found to kill the Sarcoptes mite within 5 minutes. {01} {04}

Absorption:

No data are available on percutaneous absorption of benzyl benzoate. {01} {08} Older reports suggested some percutaneous absorption, but the amount was not quantified. {01} {07}

Biotransformation:

If topical benzyl benzoate is systemically absorbed, it is rapidly hydrolyzed to benzoic acid and benzyl alcohol, which is further oxidized to benzoic acid. The benzoic acid is conjugated with glycine to form hippuric acid. {01}

Elimination:
    Excreted in the urine primarily as hippuric acid. {01}


Precautions to Consider

Mutagenicity

Benzyl benzoate has not been shown to cause mutagenic effects. {01}

Pregnancy/Reproduction

Problems in humans have not been documented. {01} {02} {04} {08} {09} However, the manufacturer recommends that benzyl benzoate not be used in pregnant women unless considered essential. {02} {04} {15}

Breast-feeding

Problems in humans have not been documented. {01} {08} However, the manufacturer recommends that breast-feeding be suspended during treatment and reinstated only after the medication has been discontinued. {02} {04}

Pediatrics

Appropriate studies on the relationship of age to the effects of benzyl benzoate have not been performed in the pediatric population. However, no pediatrics-specific problems have been documented to date.


Geriatrics


Although appropriate studies on the relationship of age to the effects of benzyl benzoate have not been performed in the geriatric population, no geriatrics-specific problems have been documented to date. However, elderly patients are more likely to have age-related xerosis of the skin, which may make their skin more susceptible to the drying effects of benzyl benzoate, and irritation may be worse in this age group. An alternative medication may need to be considered. {01}

Medical considerations/Contraindications
The medical considerations/contraindications included have been selected on the basis of their potential clinical significance (reasons given in parentheses where appropriate)— not necessarily inclusive (» = major clinical significance).


Risk-benefit should be considered when the following medical problems exist
» Hypersensitivity to benzyl benzoate, history of{08}
» Inflammation of skin, acute, or with raw, weeping surfaces    (condition may be exacerbated because more benzyl benzoate may be absorbed, therefore causing more irritation of the skin {01} {08} {16})




Side/Adverse Effects

Note: Benzyl benzoate applied topically at recommended doses appears to have a low order of toxicity. {08}

The following side/adverse effects have been selected on the basis of their potential clinical significance (possible signs and symptoms in parentheses where appropriate)—not necessarily inclusive:

Those indicating need for medical attention only if they continue or are bothersome
Incidence less frequent or rare
    
Irritation of skin, slight{01}{02}{04}{05}{08} (burning sensation; itching)





Overdose
For more information on the management of overdose or unintentional ingestion, contact a Poison Control Center (See Poison Control Center Listing ).

The following effects have been selected on the basis of their potential clinical significance (possible signs and symptoms in parentheses where appropriate)—not necessarily inclusive:

Acute and chronic effects

CNS convulsions or excitations{01}{02}{04}{05}{08} (muscle spasm or jerking of all extremities; sudden loss of consciousness)

contact dermatitis with repeated use{01}{05}{08} (blister formation, crusting, itching, oozing, reddening, or scaling of skin)

urinary retention{01}{02}{04}{05}{08} (difficulty in passing urine [dribbling])

Treatment of overdose
Recommended treatment consists of the following:


To decrease absorption:
For accidental ingestion, emesis or gastric lavage should be induced. {01} {02} {04} {05}



Specific treatment:
The body should be washed with soap and warm water to remove excess benzyl benzoate. {01} {02} {04} {05}

Anticonvulsants may be given to control convulsions. {01} {02} {04} {05}



Supportive care:
Symptomatic treatment. {02} {04} {05}



Patient Consultation
As an aid to patient consultation, refer to Advice for the Patient, Benzyl Benzoate (Topical).

In providing consultation, consider emphasizing the following selected information (» = major clinical significance):

Before using this medication
»   Conditions affecting use, especially:
Sensitivity to benzyl benzoate {08}

Pregnancy—Not recommended for use in pregnant women unless considered essential {02} {04} {15}





Breast-feeding—Suspension of breast-feeding recommended during treatment {02} {04}





Use in the elderly—Skin of older people may be more susceptible to the drying and irritating effects of benzyl benzoate {08}
Other medical problems, especially severe inflammation of skin {01} {08}

Proper use of this medication
Reading patient directions carefully before using {02}

» Importance of using the medication only as directed {02}

» Avoiding contact with the eyes and mucous membranes {01} {02} {04} {05} {08}

» Not using on open wounds, such as cuts or sores on skin or scalp, to minimize systemic absorption {01} {02} {04} {05} {08}

If necessary, treating other members of household and close contacts, especially sexual partner or partners, since infestation may spread to persons in close contact; checking with doctor if these persons have not been examined or if there are any questions {01} {02}

For lice—Proper administration {01} {02} {04} {05} {06} {08} {12}
Shampooing, rinsing, and drying hair and scalp well before using benzyl benzoate if hair or scalp has any cream, lotion, ointment, or oil-based product on it

Applying enough benzyl benzoate to thoroughly wet the dry hair and scalp or skin

Leaving benzyl benzoate on affected areas for 24 hours

Removing benzyl benzoate by washing thoroughly with soap or with regular shampoo and warm water

Rinsing thoroughly; drying with clean towel

When hair is dry, combing with a fine-toothed comb (less than 0.3 mm between the teeth) to remove any remaining nits or nit shells, or using tweezers or fingernails to pick out nits for persons with fine hair

For scabies—Proper administration {01} {02} {04} {05} {06} {08}
Washing, rinsing, and drying skin well before using benzyl benzoate if skin has any cream, lotion, ointment, or oil on it

Drying skin well if bath or shower is taken before use of benzyl benzoate

Applying enough benzyl benzoate to dry skin to cover entire skin surface from neck down, including soles of feet; rubbing in well

Leaving benzyl benzoate on skin for 24 hours

Removing benzyl benzoate by washing thoroughly with soap and warm water

Rinsing thoroughly; drying with clean towel
Washing hands immediately after using to remove any benzyl benzoate that may be on them

Repeating treatment for severe infestation {01} {02} {04}

» Proper dosing

» Proper storage

Precautions while using this medication {12}

To help prevent reinfestation or spread of infestation to other persons

For lice
Disinfecting or washing combs, curlers, and brushes in very hot water for about 10 minutes immediately after using

Washing all recently worn clothing and used bed linens and towels in very hot water or dry-cleaning

Sealing stuffed toys and other non-washable articles in a plastic bag for 2 weeks, or placing these items in the freezer (in sealed plastic bags) for 12 to 24 hours

Vacuuming all rugs, mattresses, pillows, furniture, and car seats to remove fallen hairs with lice

For scabies
Washing all recently worn clothing such as underwear and pajamas, and used sheets, pillowcases, and towels in very hot water or dry-cleaning


General Dosing Information
To minimize systemic absorption, benzyl benzoate should not be used on open wounds, such as cuts or sores on skin or scalp.

Sexual partners and other persons in close contact or living in the same household should be checked for infestation and treated if necessary, since the infestation may spread to persons in close contact {01} {02} {08}.

To help prevent reinfestation or spreading of the infestation, all recently worn clothing such as underwear and pajamas, and used sheets, pillowcases, and towels should be washed in very hot water or dry-cleaned {01} {02} {08} {12}.

Itching due to circulating antigens from scabies may persist for up to 2 weeks after successful treatment. Further treatment with benzyl benzoate is not advisable; use of a topical corticosteroid is recommended. {01}

Treatment may be repeated for severe infestation {01} {02} {04}.

A follow-up examination one week after the last treatment is recommended to confirm disinfestation of lice {02} {04}.

For treatment of adverse effects
Recommended treatment consists of the following

   • For severe skin reaction, the medication should be washed off with soap and warm water. {02} {08}


Topical Dosage Form

Note: Because benzyl benzoate is not commercially available in the U.S. or Canada, the bracketed information and the use of superscript 1 in the Dosage Forms section reflect the lack of labeled (approved) indications for this product.

BENZYL BENZOATE EMULSION

Usual adult and adolescent dose
[Pediculosis]1
Topical, one application to the affected areas as a 25% emulsion; emulsion should remain on the affected areas for twenty-four hours. Treatment may be repeated two or three times, if necessary, for severe infestation. {01} {02} {04} {08} {10}

[Scabies]1
Topical, one application to the entire body except the head and face as a 25% emulsion, which should remain for twenty-four hours. Treatment may be repeated anytime within five days if necessary. Alternatively, the emulsion may be applied three times at twelve-hour intervals. {01} {02} {04} {05} {08} {10}


Usual adult prescribing limits
No more than three applications within five days. {01} {02} {04} {05} {08} {10}

Usual pediatric dose
See Usual adult and adolescent dose. {01} {02} {04} {05} {08} {10}

Note: To minimize the risk of irritation, dilute with water as follows— {01} {02} {04} {05}
For infants: Dilute with 3 parts water.
For older children: Dilute with an equal quantity of water.


Strength(s) usually available
U.S.—
Not commercially available.

Canada—
Not commercially available.

Other (United Kingdom)—


25% (OTC) [Ascabiol{01}{02}{04}{05}{10}]

Packaging and storage:
Store below 25 °C (77 °F), in a well-closed container. Protect from light. Protect from freezing. {01} {02} {04} {05} {08} {15}

Auxiliary labeling:
   • For external use only.
   • Shake the bottle before use.
   • Keep out of reach of children.
   • When dispensing, include patient instructions.



Developed: 01/21/1994



References
  1. Dollery C, editor. Therapeutic drugs. Edinburgh: Churchill Livingstone, 1991: 53-4.
  1. Ascabiol package insert (May and Baker, Rhone-Poulenc—UK), Rev 7/90, Rec 8/93.
  1. Robertson D, Maibach H. Dermatologic pharmacology. In Katzung BG, editor. Basic and clinical pharmacology. Norwalk: Appleton and Lange, 1992: 871-7.
  1. Ascabiol data sheet (Rhone-Poulenc Rorer—UK), Rec 8/93.
  1. Reynolds JEF, editor. Martindale, the extra pharmacopeia. 30th ed. London: The Pharmaceutical Press, 1993: 1124.
  1. Landegren J, Borglund E, Storgards K. Treatment of scabies with disulfiram and benzyl benzoate emulsion: a controlled study. Acta Derm Venereol (Stockh) 1979; 59(3): 274-6.
  1. Gray AMH. Treatment of scabies. BMJ 1942; 2: 170-3.
  1. McEvoy GK, editor. AHFS Drug information 93. Bethesda, MD: American Society of Hospital Pharmacists, 1993: 2199.
  1. Koren G, editor. Maternal-fetal toxicology. A clinicians' guide. New York: Marcel Dekker, Inc., 1990: 59.
  1. Monthly Index of Medical Specialties. London: Haymarket Publishing Services Ltd., 1993 Feb: 239.
  1. VA Medication Classification System. USP DI 1993: 2862.
  1. Dewar J, editor. The practical touch. Can Pharm J 1993; 1(3): 1.
  1. Orkin M, Epstein E Sr, Maibach HI. Treatment of today's scabies and pediculosis. JAMA 1986; 236: 1136-9.
  1. Burkhart CG. Scabies: an epidemiological reassessment. Ann Intern Med 1983; 98: 498-503.
  1. Panel comment, 11/93.
  1. Panel comment, 11/93.
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