Rafoxanide and Closantel Toxicity
By Dr Mackie Hobson BSc(Agric),BVSc

Tuesday, 18th April 2017

Roundworm treatments  containing Rafoxanide and Closantel (Group 4 and in combinations) can potentially cause blindness in Angora goats if overdosed.


Trials indicated that kids dose at 4x the therapeutic dose went blind.

Kids not affected too badly recovered over 3-4 weeks


Most frequent symptoms of closantel toxicity:

  • Loss of appetite
  • Ataxia (uncoordinated movements)
  • Weakness
  • Visual disturbance
  • Blindness

Other symptoms reported in sheep: depression,  colic,  opistothonus (severe hyperextension of head, neck and spine), nystagmus (uncontrolled eye movements), mydriasis (dilatation of the pupil), loss of pupillary reflex and blindness. Fatalities can also occur.

Once blindness appears it is usually irreversible.

How fast does the toxicity occur?

Peak plasma levels are reached 10 to 48 hours after administration, both after oral or intramuscular administration

Four days after treatment up to 60% of the injected and 30% of the drenched closantel is absorbed into the blood. In the blood, unchanged closantel binds strongly and almost completely (>99%) to plasma albumins.


Antidote and Treatment:

There is no specific antidote for closantel.

Treatment consists in supportive and symptomatic measures.


Which anthelmintics contain Closantel and Rafoxanide?

See our website for Halogenated salicyclanalides (Group 4) and Combinations containing these drugs



PARASITIPEDIA.net CLOSANTEL: SAFETY SUMMARY for VETERINARY use in CATTLE, SHEEP and GOATS. Poisoning, intoxication, overdose, antidote

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