WHO Acute Hazard classification of pesticides: Not listed.

Mechanism of action of Metaflumizone

Metaflumizone's molecular mode of action consists in blocking the sodium channels in the nerve cells of the target insects. This causes paralysis and death of the affected insects.

Acute Toxicity and Tolerance of Metaflumizone

  • LD50 acute, rats, p.o. >5000 mg/kg
  • LD50 acute, rats, dermal >5000 mg/kg
  • Cats treated a total of 7 times every two weeks at 3x and 5x the recommended didn't show toxic effects.
  • Tolerance studies suggest that both dogs and cats tolerate metaflumizone quite well.

Toxic Symptoms caused by Metaflumizone Poisoning

  • Transient hypersalivation (drooling) has been reported immediately after administration due to licking of the application site.
  • A few cases of skin irritation and hair loss at the application site have also been reported.

Metaflumizone Side Effects, Adverse Drug Reactions (ADRs) and Warnings

  • At therapeutic doses hypersalivation, sin irritation and hair loss have been reported.
  • Due to its recent introduction experience on use on dogs and cats is still scarce.
  • Never use spot-ons for dogs in cats; never use spot-ons for large dogs in small dogs. It happens that some users want to save money buying large spot-ons for treating smaller dogs (or even cats!) twice or more times. The risk of overdosing is considerable, either due to erroneous calculations or to unskilled manipulation. In addition, dog medicines may sometimes contain other ingredients that are toxic to cats.

Antidote and Treatment of Metaflumizone Intoxication

  • There is no antidote for metaflumizone poisoning.
  • Treatment consists in preventing further exposure together with supportive and symptomatic measures.
  • In case of heavy poisoning the liver is the most affected organ.

Pharmacokinetics of Metaflumizone

  • Following oral administration to rats, absorption into the bloodstream was rather low. Most of the administered dose was excreted through feces.
  • Absorbed metaflumizone is extensively metabolized, and several metabolites can be detected in blood, bile and urine.
  • After topical administration to dogs absorption through the skin is very low. However, treated animals may ingest metaflumizone through licking or grooming.

Environmental Toxicity of Metaflumizone

  • Metaflumizone is slightly toxic to birds and moderately toxic to fish and aquatic crustaceans. 
  • Extensive studies on its environmental fate and impact have been carried out for its use in crop pesticides.
  • Correct use on dogs and cats is unlikely to have a negative environmental impact.

Additional information

Click here for a list and overview of all safety summaries of antiparasitic active ingredients in this site.

  • Metaflumizone belongs to the chemical class of the semicarbazones.
  • Metaflumizone is not used in human medicines.
  • Metaflumizone is used in crop pesticides.
  • Metaflumizone is used in public and domestic hygiene as a biocide.
  • Click here for General safety of antiparasitics for domestic animals.
  • Click here for General safety of antiparasitics for humans.
  • Click here for General safety of antiparasitics for the environment.
  • Click here for technical and commercial information on metaflumizone.

PFIZER (now ZOETIS) discontinued marketing of PROMERIS and PROMERIS DUO in 2011, the two major products containing metaflumizone for dogs and cats, respectively. The official reason was that these products did not fit into the product portfolio of the company. But the reason may have been related ro some studies that associate both products with cases of "pemphigus foliaceus", a skin disease of pets related with immune disorders.


If you intend to use a veterinary drug containing this active ingredient you must carefully read and follow the safety instructions in the product label.  Always ask your veterinary doctor, or pharmacist, or contact the manufacturer. Be aware that the safety instructions for the same veterinary medicine may vary from country to country.

The information in this page must not be confused with the Materials and Safety Datasheets (MSDS) officially issued by manufacturers for active ingredients and many other chemicals. MSDSs target safety during manufacturing, transport, storage and handling of such materials. This safety summary is a complement to the information on product labels and MSDS.

The toxicity of an active ingredient must not be confused with the toxicity of finished products, in this case parasiticidal drugs or pesticides. Finished products contain one or more active ingredients, but also other ingredients that can be relevant from the safety point of view.

All information in this site is made available in good faith and following a reasonable effort to ensure its correctness and actuality. Nevertheless, no this regarding guarantee is given, and any liability on its accuracy, integrity, sufficiency, actuality and opportunity is denied. Liability is also denied for any possible damage or harm to persons, animals or any other goods that could follow the transmission or use of the information, data or recommendations in this site by any site visitor or third parties.