Ectoparasiticidal Agents

Table 3-7 Selected Ectoparasiticidal Agents in Small Animal Dermatology

Formulation

Comments

Indications

Side Effects

Dog dose (D) Cat dose (C)

Ivermectin

10 mg/kg bovine injectable solution (often given orally to small animals), 10 mg/ml equine oral solution

Idiosyncratic toxicities most common in Collies and Old English Sheepdogs, but also possible in other breeds. Gradual dose increase from 50 µg/kg on day 1 to 100 µg on day 2, 150 µg on day 3, 200 mg on day 4 and 300 mg on day 5 to identify sensitive patients before severe adverse effects occur.

Heartworm prevention. Oral and subcutaneous administration: Canine and feline scabies,Otodectes cynotisinfestations, demodicosis, cheyletiellosis, lice Topical administration: Canine scabies

Lethargy, ataxia, tremors, mydriasis, coma, respiratory arrest

Heartworm prevention at 6 µg/kg monthly. Oral and subcutaneous administration (with gradual increase from 50 to 300 µg within 4 days): 300 µg/kg daily for demodicosis until 8 weeks after the first negative skin scraping, four administrations 1 week apart for all other ectoparasites. (D, C) Topical administration: Ivermectin pour-on for cattle administered at 500 mg/kg (0.1 ml/kg) applied along the dorsal midline twice 2 weeks apart was reported to be effective for canine scabies.

Milbemycinoxime

2.3 mg, 5.75 mg, 11.5 mg and 23 mg tablets

Fairly costly

Heartworm prevention, scabies, demodicosis

Very safe drug

Heartworm prevention: 1 mg/kg monthly. Scabies: 2 mg/kg twice weekly for 4 weeks. Demodicosis: 2 mg/kg daily until 8 weeks after the first negative skin scraping for demodicosis. (D, C)

Lufenuron

45 mg, 90 mg, 204.9 mg, 409.8 mg tablets (dogs), 135 mg, 270 mg suspension (cats)

All household animals need to be on lufenuron for effective treatment. Breaks life cycle, no significant adulticidal activity.

Flea infestation

Very safe drug

10-15 mg/kg once monthly orally with food (D, C) or injectable every 6 months (C).

Amitraz

10.6 ml, 50 ml concentrate

Animal must not get wet in between rinses. Animals should not be rinsed when wet. Asthmatic people should not perform the rinse.

Canine demodicosis, cheyletiellosis, scabies and Otodectes cynotisinfestation

Sedation, pruritus, hypothermia, hyperglycemia, hypotension

Mix 10.6 ml in 2 gal of water (D) and rinse q 7- 14 days. Continue for 8 weeks (D) after the first-negative scraping.

Lyme sulfur

97.8% sulfurated lime solution

Safe for even puppies and kittens

Cheyletiellosis, scabies, Otodectes cynotisinfestation. Feline demodicosis

Very safe drug

Dilute 1 part to 32 parts water, apply as rinse or dip weekly for 4 weeks (D, C)

Fipronil

0.29% spray in 100 and 250 ml bottles, 9.7% solution (0.5 ml, 0.67 ml, 1.34 ml, 2.68 ml)

Spray more effective than spot-on formulation, but strong smell unavoidable during application. For highest efficacy, animals may be shampooed 48 hours before application, but not any sooner; exposure to water does not interfere with efficacy.

Flea-bite hypersensitivity, ticks, possibly scabies and cheyletiellosis

Temporary irritation at site of application, rare hypersensitivities. Contraindicated in rabbits

Spray: 4-6 ml/kg q 2-12 weeks (8-12 pumps using the 100 ml bottle, 2-4 pumps using the 250-ml bottle). (D, C) Spot-on: Apply once monthly

Selamectin

15 mg, 30 mg, 45 mg, 60 mg, 120 mg, and 240 mg tubes.

Cosmetically appealing, disperses quickly. Too early to comment further at time of writing

Flea-bite hypersensitivity, Otodectes cynotisinfestation, scabies, heartworm prevention, roundworm, and hook-worm infestations

Focal alopecia (reversible)

6-12 mg/kg monthly as a spot-on. (D, C)

Imidacloprid

9.1% solution (0.4 ml, 0.8 ml, 1 ml, 2.5 ml, 4 ml tubes)

Frequent shampoo therapy or water exposure will significantly decrease efficacy. Solvent may discolor lacquer on furniture.

Flea-bite hypersensitivity

Focal alopecia

0.4 ml (C)< 4 kg, 0.8 ml (C) > 4 kg. 0.4 ml (D) > 5 kg, 1 ml (D) 5-10 kg, 2.5 ml (D) 10 – 25 kg, 4 ml (D) > 25 kg

Pyrethrin

Sprays and powders at 0.05-0.2%

Repellent as well as adulticide. Low toxicity potential, salivation in cats

Flea-bite hypersensitivity

Ptyalism, tremors, ataxia, vomiting, depression, hyperaesthesia, seizures, dyspnea

Use q 24-72 h (D, C)

Permethrin

Sprays, spot-ons and shampoos at 0.2-2%

Repellent as well as adulticide. Low toxicity in dogs. Not to be used in cats!

Canine flea-bite hypersensitivity

Ptyalism, tremors, ataxia, vomiting, depression, hyperaesthesia, seizures, dyspnea

Use q 3-10 days (D)

Table 3-8 Administration, Advantages, and Disadvantages of Selected Flea Control Products

Administration

Advantages

Disadvantages

Comments

Insect growth regulators/development inhibitors

Fenoxycarb

Indoors: spray q 12 m. Outdoors: Spot treatment of allergic pet's favorite spots q 6-12 m in dry environments.

Comparatively safe and effective, rapid onset of action

Work-intensive

Foggers are more convenient but do not cover more than 2 rooms/can. The insecticide stays on shelves and furniture, but areas underneath furniture are not covered! Sprays are less convenient and more work-intensive, but insecticide is deposited only where needed. Use in all rooms with pet access! Carpeted areas, crevices, and corners as well as areas underneath furniture are most important. Indicated with frequent visiting animals not on flea control as well as at the start of an insect-control trial.

Lufenuron

10-15 mg/kg q 30 d orally (D), 25-50 mg/kg SC q 6 m (C).

Convenient, safest environmentally

Expensive in multi-pet households, lag period of several weeks to months.

Indicated in house-holds with few pets and no visits from animals without thorough flea control.

Methopreneor Pyriproxifen

Indoor spray q 6 m

Comparatively safe and effective, rapid onset of action.

Work-intensive

Foggers are more convenient, but do not cover more than 2 rooms/can. The insecticide stays on shelves and furniture, but areas underneath furniture are not covered! Sprays are less convenient and more work-intensive, but insecticide is deposited only where needed. Use in all rooms with pet access! Carpeted areas, crevices, and corners, as well as areas underneath furniture most important. Indicated with frequent visiting animals not on flea control as well as at the start of an insect-control trial.

Adulticides

Fipronil

0.29 g/100 ml, 10-15 mg/kg as a spray distributed over the whole body q 2-8 week, spot-on q 2-8 week

Water-proof (but not shampoo proof!), convenient, because used only every 2-4 weeks

No repelling action, expensive in large animals, viable egg production possible.

Spray needs to be applied carefully, covering the animal's whole body. Spot-on formulation easier to apply, but less effective. Administer outdoors or in well-ventilated area due to strong smell during first minutes. Shampoo only 2 days before new application.

Imidacloprid

100 mg/ml

Convenient, because used only every 2-4 weeks, easy to apply

Not water proof, no repellingviable egg production possible.

Shampoo only 2 days before new application. Swimming or roaming in rainy weather not recommended.

Nitenpyram

Tablets q 1-2 d or as needed

Convenient, rapid onset of action, safe

Flea needs to bite animal to die, only effective for less than one day

May be given daily with no adverse effects. Particularly useful for prophylactic administration in animals on lufenuron directly before anticipated exposure in shows or visits.

Pyrethrin

Repels insects, quick knock-out

Work-intensive, rare but possible toxicities, depending on product and patient; daily-to-monthly application

Soak animal with sprays (pressure pump sprays may be useful for bigger or long-haired dogs).

Permethrin

744 mg in 1 ml as a spot- on for dogs <15 kg, 1488 mg in 2 ml for dogs >15 kg. Do not use in cats.

Repelling action, quick knock-out.

Work-intensive, rare but possible toxicities, depending on product and patient; daily-to-monthly application

Soak animal with sprays (pressure pump sprays may be useful for bigger or long- haired dogs).

Selamectin

6-12 mg/kg monthly as a spot-on

Easy to use, cosmetically appealing, safe

Too new to comment at time of writing.

Too new to comment at time of writing.

Table 3-9 Application of Selected Flea Products in Patients with Confirmed versus Suspected Flea-bite Hypersensitivity

Drug

Confirmed Flea-Bite Hypersensitivity*

Suspected Flea-Bite Hypersensitivity*

Fipronil spot-on

q 2-4 weeks

Not used for insect control trials

Fipronil spray

q 4 -12 weeks

q 7-14 d for 4-6 weeks*

Imidacloprid spot-on

q 4 weeks

q 7-14 d for 4-6 weeks*

Nitenpyram

In addition to lufenuron, when patient shows clinical signs or before suspected exposure

q 1-2 d for 4-6 weeks*

Permethrin spot-on

q 4 weeks

Not used for insect control trials

Permethrin spray

Varying depending on individual product up to q 7-14 d

Varying depending on individual product up to q 2-3 d for 4-6 weeks*

Pyrethrin spray

Varying depending on individual product up to q 7-14 d

Varying depending on individual product up to q 2-3 d for 4-6 weeks*

Selamectin

q 4 week

q 14 d for 4-6 weeks*

* In any flea control trial adulticides are combined with an insect growth regulator used in the environment at the beginning of the trial.