
Side effects generally do not occur with any anti-mange doses of ivermectin except in collies, Shetland sheepdogs, Australian shepherds, and Old English sheepdogs, though
some individual animals that are not members of these sensitive breeds may also be prone to side effects. Test doses are often recommended to identify these individuals.
Side effects of concern are: dilated pupils and drunken gait which can progress to respiratory paralysis and death.
Ivermectin should not be used in combination with valium or related tranquilizers (the infinitesimal doses used in Heartgard excepted). It should not be used in conjunction with Amitraz (Mitaban) dips nor with Amitraz tick prevention collars (Preventic collars). These medications are all members of the monoamine oxidase inhibitor group and when they used together their effects add together creating sedation and adverse neurologic effects.
Ivermectin use in pregnancy and lactation is not felt to be a problem