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Topagen Spray (Canada)

This page contains information on Topagen Spray for veterinary use.
The information provided typically includes the following:
  • Topagen Spray Indications
  • Warnings and cautions for Topagen Spray
  • Direction and dosage information for Topagen Spray

Topagen Spray

This treatment applies to the following species:
Manufacturer: Merck Animal Health


Gentamicin 0.57 mg/ml (as gentamicin sulfate, USP)

Betamethasone 0.284 mg/ml (as betamethasone valerate, USP)


For Topical Administration to Dogs Only

DIN 00602841


Gentamicin, as sulfate is a water soluble (bactericidal) antibiotic of the aminoglycoside group, derived from Micromonospora, an actinomycete.

Betamethasone valerate is a synthetic glucocorticoid derivative of prednisolone.

Each ml of TOPAGEN® spray contains 0.57 mg gentamicin (as gentamicin sulfate, USP) and 0.284 mg of betamethasone (as betamethasone valerate, USP), an aqueous solution containing polypropylene glycol, isopropyl alcohol, and with methyl and propylparabens as preservatives. The pH may be adjusted with hydrochloric acid.


Gentamicin is a mixture of the following three substances:

gentamicin C1

R = R1 = CH3

gentamicin C2

R = CH3; R1 = H

gentamicin C1a

R = R1 = H

Molecular Formula


Molecular Weight


Gentamicin C1



Gentamicin C2



Gentamicin C1A


The relative ratio of C: C1A : C2 is variable in a range of 25-60 : 10-40 : 20-50 % (Veterinary)

Betamethasone Valerate is:

9α - fluoro - 11β, 17,21 - trihydroxy - 16β - methylpregna - 1,4 - diene - 3,20 - dione 17 - valerate


Gentamicin, a broad spectrum antibiotic, is a highly effective topical treatment for bacterial infections. Gentamicin is bactericidal in vitro against a wide variety of gram-positive and gram-negative bacteria isolated from domestic animals.1,2 Specifically gentamicin is active against the following organisms: Alcaligenes sp., Citrobacter sp., Klebsiella sp., Pseudomonas aeruginosa, Proteus sp. (indole positive and negative), Escherichia coli, Enterobacter sp., Staphylococcus sp., and Streptococcus sp.

Betamethasone valerate in veterinary medicine has been shown to provide anti-inflammatory and antipruritic activity in the topical management of corticosteroid responsive infected superficial lesions in dogs.

Topagen Spray Indications And Clinical Uses

TOPAGEN® spray is indicated for the treatment, in dogs, of superficial lesions infected by the bacteria: Alcaligenes sp., Citrobacter sp., Klebsiella sp., Pseudomonas aeruginosa, indole positive and negative Proteus sp., Escherichia coli, Enterobacter sp., Staphylococcus sp., and Streptococcus sp. which are susceptible to gentamicin.

Topagen Spray Dosage And Administration

Prior to treatment, remove excessive hair and clean the lesion and adjacent area. Hold bottle upright 3 to 6 inches from the lesion and depress the sprayer head twice. Administer four times daily for 7 days.

Each depression of the sprayer head delivers 0.7 ml of TOPAGEN® spray, containing 0.4 mg gentamicin and 0.2 mg betamethasone.


If hypersensitivity to any of the components occurs, treatment should be discontinued and appropriate therapy instituted. TOPAGEN® spray is not indicated for the treatment of fungal infections of the skin of dogs.


Antibiotic susceptibility of the pathogenic organism(s) should be determined prior to use of this preparation. Use of topical antibiotics may permit overgrowth of non-susceptible bacteria, fungi or yeasts. If this occurs, treatment should be instituted with the other appropriate agents as indicated.

Administration of recommended dose beyond seven days may result in delayed wound healing. Animals treated longer than seven days should be monitored closely.

Adverse systemic reactions have been observed following the oral ingestion of some topical corticosteroid preparations. Dogs should be closely observed for the usual signs of adrenocorticoid overdosage which include sodium retention, potassium loss, fluid retention, weight gains, polydipsia and / or polyuria. Prolonged use or overdosage may produce adverse immunosuppressive effects.

Although topical steroids have not been reported to have an adverse effect on pregnancy, the safety of their use on pregnancy has not been established. Therefore, TOPAGEN® spray should not be used extensively on pregnant dogs, in large amounts, or for prolonged periods of time.


TOPAGEN® spray was well tolerated in an abraded skin study in dogs. No treatment-related toxicological changes in the skin were observed.

Systemic effects directly related to treatment were confined to histological changes in the adrenals, liver, and kidney and to organ-to-body weight ratios of the adrenals. All were dose-related, were typical for or not unexpected with corticosteroid therapy, and were considered reversible with cessation of treatment.

Side Effects

The possibility of delayed wound healing and sensitivity should be kept under consideration.

How Supplied

Available in a plastic spray bottle containing 70 ml of TOPAGEN® spray. Product code: 787070

Store upright between 2° and 30°C.


1. Hennessey PW, et al
In vitro activity of gentamicin against bacteria isolated from domestic animals.
Veterinary Medicine / Small Animal Clinician, November 1971, p. 1118-1122.

2. Bachman HJ, et al
Comparative in vitro activity of gentamicin and other antibiotics against bacteria isolated from clinical samples from dogs, cats, horses, and cattle. Veterinary Medicine / Small Animal Clinician, October 1975, p. 1218-1222.

® Registered trademark of Intervet Canada Corp.

Intervet Canada Corp., Kirkland QC, H9H 4M7

1 888 306-0069

71-422134 E


NAC No.: 12080846

Intervet Canada Corp.

Order Desk:   514-428-7013
Toll-Free:   866-683-7838
Fax:   Toll-free 888-498-4444; local 514-428-7014
Every effort has been made to ensure the accuracy of the Topagen Spray information published above. However, it remains the responsibility of the readers to familiarize themselves with the product information contained on the Canadian product label or package insert.

Copyright © 2019 Animalytix LLC. Updated: 2019-01-22