WHO Acute Hazard classification: Not listed

Mechanism of Action of Dicyclanil

The mechanism of action of dicyclanil has not been elucidated. It is certainly not a Chitin Synthesis Inhibitor like other insect growth regulators such as the benzoylureas. It seems to acts upon the molting process in a similar way as cyromazine, probably interfering with the process of chitin deposition.

Toxicity and Tolerance of Dicyclanil

  • LD50 acute, rats, p.o. 520 mg/kg
  • LD50 acute, rats, dermal, > 2000 mg/kg
  • Sheep tolerate topically applied dicyclanil very well. At 3x the recommended dose o 42 mg/kg no toxic symptoms were recorded. At 10x the recommended dose no external symptoms were observed, but significant weight increases in liver and spleen were recorded.

Toxic Symptoms caused by Dicyclanil Poisoning

  • In toxicity studies in rats the following symptoms were observed after heavy oral overdosing: piloerection (bristling of hairs), hunched posture and dyspnea (difficult breathing), ataxia (uncoordinated movements), reduced activity.
  • In toxicity studies in dogs several symptoms were observed after heavy oral overdosing: tremor, vomit, dyspnea, slight apathy and ataxia (uncoordinated movements), weight loss, reduced food consumption, unusula raised tails and frequent shaking.

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

  • As a general rule, ADRs following topical administration of dicyclanil at the recommended dose are very rare due to its low toxicity, the high safety margin and the excellent tolerance of sheep and goats.

Antidote and Treatment of Dicyclanil Intoxication

  • There is no antidote for dicyclanil poisoning.
  • Treatment consists in supportive and symptomatic measures.

Pharmacokinetics of Dicyclanil

  • Topically administered dicyclanil is poorly absorbed through the skin of sheep (2% to 4%). The absorbed dicyclanil is partly metabolized and excreted through both urine (mainly metabolites) and feces (mainly unchanged dicyclanil).
  • About 95% of the administered dose is excreted in the 7 days following treatment.

Environmental Toxicity of Dicyclanil

  • Dicyclanil is slightly toxic to fish and moderately toxic to birds.
  • Dicyclanil is highly toxic to Diptera and Siphonaptera, but only slightly hazardous for other arthropods.
  • Dicyclanil is poorly photodegradable in aqueous environment, but it degrades rapidly (half-life ~20 days) in moist soil under aerobic conditions.
  • Dicyclanil does not accumulate in soil or in the chain food.
  • Correct use on sheep dicyclanil is unlikely to be directly detrimental for the environment.
  • In Australia, it was concluded that dicyclanil scour residues from the wool industry were unlikely to be harmful for the environment.

Additional Information

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

  • Dicyclanil is an insect growth regulators (IGR) that belongs to the chemical class of the cyano-pyrimidines.
  • Dicyclanil is not used in dogs or cats.
  • Dicyclanil is not used in human medicines.
  • Dicyclanil is not used in crop pesticides.
  • Dicyclanil is not used in biocides for public or domestic hygiene.
  • 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 dicyclanil.


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.