2010, Vol. 5 No. 1, Article 58

Ivermectin Toxicity in Pomeranian Pup – A Case Study

Rajneesh Pathania*¹ and Vinay Kant²

¹Veterinary Officer, Tihra, Himachal Pradesh
²Assistant Professor, Dept. of Vety. Pharmacology and Toxicology,
COVAS, Palampur (Himachal Pradesh)

*Corresponding Author; e-mail address: [email protected]

ABSTRACT

A Pomeranian pup aged one month developing symptoms of depression, hind limb ataxia, in -coordination, tremors, behavioral disturbances, weakness, recumbency and hypersalivation about 6 hours after subcutaneous administration of 0.6 ml ivermectin (Ivomec). Administration of neostigmine 0.2 ml intravenous and dexamethasone 1ml intramuscular twice a day with infusion of dextrose saline (5%) 200 ml i/v cured the pup completely.

KEY WORDS

Ivermectin, Pomerian, Toxicity.

CASE HISTORY and clinical signs

A Pomeranian pup aged one month was presented to Veterinary hospital at Tihra, Mandi (H.P.), with the complaint of developing symptoms of depression, hind limb ataxia, in-coordination, tremors, behavioral disturbances, weakness, recumbency and hypersalivation (drooling saliva). The animal had been injected 0.6 ml of ivermectin (Ivomec) subcutaneously about 6 hours earlier, to treat  ectoparasites.
The clinical examination revealed miosis, tachycardia (110 beats/minute), hypothermia (99.2ºF), difficulty in breathing with a respiration rate of 16 per minute. Haematological tests gave values of haemoglobin, packed cell volume, total erythrocytes count and total leucocytes count within normal range

DIAGNOSIS AND TREATMENT

On the basis of the history and clinical signs the case was diagnosed to be of ivermectin toxicity. There is no specific antidote for ivermectin toxicity and only managemental care, supportive and symptomatic treatments are effective. The pup was administered a 0.2 ml intravenous injection of neostigmine and 1ml intramuscular injection of dexamethasone twice in a day. Additionally, dextrose saline (5%) 200 ml i/v over a period of 1 hour was also administered. Within 8 hours of therapy, the hypersalivation disappeared and there was moderate improvement in the depression and tremors. The pup recovered fully after 2 days.

DISCUSSION

Collie breed of dogs are more susceptible to ivermectin and tolerate only up to 0.1 mg/kg dose rate of ivermectin (Paul 1987). The margin of safety for ivermectin in most breeds of dog is well over 100 times the recommended dose but in Collies it is about 16 times the usual dose. Clinical signs of toxicity were reported in two Australian shepherds receiving ivermectin at oral dosage of 0.17 mg/kg and 0.34 mg/kg respectively (Hadrick et al., 1995). Occurrence of toxicity in selective breeds, may be due to the reason that these breeds have comparatively more permeable blood brain barrier to the drug (Houston et al; 1987) or due to an autosomal recessive trait (MDR-1) gene that causes a defect in the p-glycoprotein, which is a multidrug transporter in the blood brain barrier and this leads to passage of ivermectin in to the brain at low dosages thus causing toxicity (Kant, 2007). In present case, the animal was young and the blood brain barrier might not have been fully developed leading to toxicity.

REFERENCES

1. Hadrick M, Bunch S and Kornegay J. Ivermectin toxicosis in two Australian shepherds. J Am Vet Med Assoc 1995; 206 (8): 1147.

2. Houston D, Parent J and Matushek K. Ivermectin toxicosis in dogs. J Am Vet Med Assoc1987; 191 (1) : 78.

3. Kant V. Ivermectin toxicity in Dogs and Cats. Pashudhan 2007; 33(11) : 5.

4. Paul A, Tranquilli W, Seward R, et al. Clinical observations in collies given ivermectin orally. Am J Vet Res (1987) ; 48(4) : 684.