This is the message that I've been taking to get out regarding heartworm medication and medications in general. Always monitor your dogs when starting any new medication.
All heartworm medications are on the MDR1 list at high doses. All of them not just Ivermectin. All of them are considered safe at low doses even ivermectin. But indivdual sensitives do occur regardless of breed and mutant status as shown by Sharon7's normal MDR1 dog.
From the WSU website:I only listed the heartworm meds.
Drugs that have been documented to cause problems in dogs with the MDR1 mutation include
Ivermectin (antiparasitic agent). While the dose of ivermectin used to prevent heartworm infection is SAFE in dogs with the mutation (6 micrograms per kilogram), higher doses, such as those used for treating mange (300-600 micrograms per kilogram) will cause neurological toxicity in dogs that are homozygous for the MDR1 mutation (mutant/mutant) and can cause toxicity in dogs that are heterozygous for the mutation (mutant/normal).
Selamectin, milbemycin, and moxidectin (antaparasitic agents). Similar to ivermectin, these drugs are safe in dogs with the mutation if used for heartworm prevention at the manufacturer's recommended dose. Higher doses (generally 10-20 times higher than the heartworm prevention dose) have been documented to cause neurological toxicity in dogs with the MDR1 mutation.
Selamectin is Relovution, Milbemycin is Interceptor, Moxidectin is Advantage Multi or Proheart
