Levamizole toxicity
By Dr Mackie Hobson BSc(Agric),BVSc

1. Poisoning
2. Drugs

Levamizole  toxity has been seen in Angora goats  due to overdosing.

The symptoms appear very quickly and it has been known for an Angora goat farmer to see symptoms while still dosing a flock of Angoras.

Symptoms may appear 5-15 minutes after dosing but usually peak after 30 minutes.

The general off label dose of anthelmintic advised in goats is 1.5-2X that of the sheep dose.

Levamizole has a narrow toxic range compared to most anthelmintics and so should be used with care in Angora goats. Toxic levels may be reached at 4x (some authors suggest 2x) the therapeutic dose. In Angora goats, oral doses of 35 mg/kg (usual therapeutic dose ~8 mg/kg) may cause toxicity. A 10X dose will cause death. The cases where deaths have occurred in Angora goats have been associated with those doses that are reconstituted from powder form and the farmer has made a decimal point dilution error resulting in 10x overdose.

Toxic Symptoms caused by Levamisole Poisoning:

• Restlessness, hyperactivity
• hypersalivation (drooling),
• abdominal pain, colic,
• diarrhea, hiccups
• bradycardia (low heart rate), collapse.
• dyspnea (difficult breathing), tachypnea (rapid breathing).
• Nervous symptoms: miosis (contraction of the pupil), spasms, cramps, trembling,
• Depression
• In extreme cases death can follow within 1 hour after administration due to respiratory failure.

The symptoms can appear after 5-15 minutes and also resolve fast (1- 6 hours).

Antidote and Treatment of Levamisole Intoxication

There is no specific antidote for levamisole.

• Activated charcoal should be tubed/dosed (2mg/kg)
• Atropine can be useful against CNS symptoms. But atropine alone does not reduce mortality after levamisole intoxications.
• Where suspected ‘allergic’ reaction anti-histamines can be given.

Which doses contain Levamisole?

See our website GROUP 3 (Imidazoles) and Combinations

https://www.angoras.co.za/page/anthelmintic_drug_list#38