Treatment of Bacterial Infection

Table 3-2. Selected Antibiotics in Small Animal Dermatology

Drug

Formulation

Comments

Adverse Effects

Indications

Dog Dose (D)

Cat Dose (C)

Trimethoprim/

sulfamethoxazole

5/25 mg and 20/100 mg coated tablets, 40 mg/ 200 mg, 80 mg/400 mg, and 160 mg/800 mg tablets, 8 mg/40 mg/ml syrup

Not for Doberman Pinschers.Resistance pattern varies, low in England and the United States, high in Australia

Keratoconjunctivitis sicca, drug reactions (cutaneous eruptions, polyarthritis, bone marrow suppression), hepatotoxic, gastrointestinal symptoms, fever, hypothyroidism with extended use

Infections with gram-positive bacteria. Many gram-negative organisms of the family Enterobacteriaceaeare Pseudomonas aeruginosa also susceptible (but not)

15-30 mg/kg q 12 h (D,C)

Trimethoprim/

sulfadiazine

180 mg/820 mg tablets, 9 mg/41 mg/ml syrup

Not for Doberman Pinschers.Resistance pattern varies, low in England and the United States, high in Australia

Keratoconjunctivitis sicca, drug reactions (cutaneous eruptions, polyarthritis, bone marrow suppression), hepatotoxic, gastrointestinal symptoms, fever, hypothyroidism with extended use

Infections with gram-positive bacteria. Many gram-negative organisms of the familyEnterobacteriaceae are also susceptible (but not Pseudomonas aeruginosa)

15-30 mg/kg q 12 h (D, C)

Erythromycin

250 mg and 500 mg tablets, 500 mg coated tablets, 20 mg/ml, 40 mg/ml, 80 mg/ml, 120 mg/ml syrup

Give without food. Inexpensive! Resistance develops relatively quickly. Do not administer concurrently with terfenadine, cyclosporine, or ketaconazole

Vomiting, diarrhea, nausea

Bacterial superficial pyoderma

15 mg/kg

q 8 h without food (D,C)

Lincomycin

200 and 500 mg tablets, 500 mg capsules

Give without food. Contraindicated in rabbits, hamsters, and guinea pigs!

Vomiting, diarrhea (less common than with erythromycin)

Infections with most gram-positive cocci including Staphylococci Nocardia and Actinomyces may also be susceptible

20-30 mg/kg q 12 h without food (D, C)

Penicillin V

125, 250, 500 mg tablets, 25 mg/ml and 50 mg/ml oral suspension

Not commonly used in dermatology because most strains of Staphylococcus intermedius strains are resistant to penicillin

Gastrointestinal signs with oral administration, hypersensitivity reactions

Infections with Actinomyces, most spirochetes and gram-positive and gram-negative cocci, which do not produce penicillinase

10 mg/kg

q 6-8 h (D, C)

Amoxycillin

500 mg, 750 mg, 1000 mg tablets, 50 mg/ml syrup

Not commonly used in dermatology because most Staphylococcus intermedius strains are resistant to amoxycillin

Vomiting, diarrhea, allergic reactions

Most organisms that cause skin disease are resistant to ampicillin and amoxycillin, thus it is rarely indicated

10-20 mg/kg

q 8 h (D, C)

Clavulanic acid/amoxycillin

12.5/50 mg, 62.5/250 mg, 125/500 mg tablets, 12.5/50 mg syrup

In vitro resistance of Staphylococciextremely low, but sensitivity in vitronot always correlating with results in vivo. May be more efficacious with q 8 h administration

Vomiting, diarrhea, allergic reactions

Bacterial pyoderma

12.5-25 mg/kg

q 8-12h (D, C)

Cloxacillin

250 mg and 500 mg capsules, 25 mg/ml solution

Effective against most gram-positive cocci

Vomiting, diarrhea, allergic reactions

Pyoderma caused by sensitive cocci

20-40 mg/kg

q 8h (D, C)

Cephalexin

500 mg, 1000 mg tablets, 250 mg, 500 mg capsules, 75 mg, 300 mg, 600 mg tablets, 50 mg/ml syrup

Used commonly in veterinary dermatology

Vomiting and diarrhea; very rarely excitability, tachypnea or blood dyscrasias

Superficial and deep bacterial pyodermas

20-30 mg/kg

q 8-12h (D, C)

Cefadroxil

1000 mg tablets, 50 mg/ml syrup

-

Vomiting and diarrhea, very rarely tachypnea or blood dyscrasias

Superficial and deep bacterial pyodermas

20-30 mg/kg

q 8-12 h (D, C)

Tetracycline

250 mg, 500 mg capsules

Should not be given with amphotericin B or erythromycin. In veterinary dermatology used for immunomodulatory effects

Nausea, vomiting, discoloration of teeth in puppies and kittens, phototoxic reactions, hepatotoxicity

In combination with niacinamid used for the treatment of discoid lupus erythematosus, idiopathic onychomadesis

250-500 mg/animal

q 8 h (in combination with niacinamide at 250-500 mg/animal q8h) (D, C)

Doxycyline

50 mg, 100 mg, 200 mg capsules, 100 mg/ml paste, 1 mg/ml, 5 mg/ml suspension

Also used for effects on cells of the immune system and cytokine production

Nausea, vomiting, discoloration of teeth in puppies and kittens; phototoxic reactions

Bacterial superficial pyoderma, mycobacterial infections, discoid lupus erythematosus

2.5-5 mg/kg q 24 h (if used for immune-mediated diseases, it is combined with niacinamide at 250-500 mg/animal q8h) (D, C)

Clindamycin

75 mg, 150 mg, 300 mg capsules

Bacterial superficial pyoderma, mycobacterial infections, discoid lupus erythematosus

Skin rashes, vomiting, diarrhea

Infections with gram-positive cocci, most anaerobic organisms, Nocardia, Actinomyces

5-10 mg mg/kg q 12h (D, C)

Enrofloxacin

5.7 mg, 22.7 mg, 50 mg, 68 mg, 136 mg, 150 mg tablets

Not in immature animals! Ineffective against anaerobic organisms. Resistance may occur, particularly to Pseudomonas

Cartilage erosions in puppies, vomiting and diarrhea. Hypersensitivities and CNS signs could potentially occur. Crystalluria may occur in dehydrated animals

Infections with staphylococci, mycobacteria, most gram-negative organisms

5-20 mg/kg q 24 h (D) 5 mg/kg q 24 h (C)

Ciprofloxacin

100 mg, 250 mg , 500 mg, 750 mg coated tablets

Ineffective against anaerobe organisms. Resistance may occur, particularly to Pseudomonas

Cartilage erosions in puppies; vomiting and diarrhea. Hypersensitivities and CNS signs could potentially occur. Crystalluria may occur in dehydrated animals

Infections with staphylococci, mycobacteria, most gram-negative organisms

5-15 mg/kg q 12 h (D, C)

Marbofloxacin

25-mg, 50-mg, 100-mg, 200-mg scored coated tablets

Not in immature animals! Ineffective against anaerobe organisms. Resistance may occur, particularly to Pseudomonas

Cartilage erosions in puppies, vomiting and diarrhea. Hypersensitivities and CNS signs could potentially occur

Infections with staphylococci, mycobacteria, most gram-negative organisms

2.5-5 mg/kg q 24 h without food (D, C)

Mupirocin

2% ointment

Effective against gram-positive organisms, particularly Staphylococci

-

Localized superficial bacterial infections, feline acne

Apply to affected areas q 12 h, prevent animal from licking area for 10 minutes (D, C)