Defenza 400 mg is an oral antiparasitic medication indicated for dogs weighing between 20 and 40 kg. Its active ingredient is fluralaner, which offers protection against fleas, ticks, mange (demodectic and otodectic) and chigoe (Tunga penetrans), lasting up to 37 days, and is one of the longest-acting monthly treatments available on the market. The medication comes in a chewable tablet with a pork liver flavor, making it easy to administer, as it is well accepted by most dogs. Its action is systemic, ensuring uniform efficacy throughout the animal's body and is not affected by bathing. How to use and dosage: Single monthly dose. The tablet should not be divided. For dogs weighing between 20 and 40 kg, one 400 mg fluralaner tablet is used. Precautions and contraindications: Do not use in dogs under 8 weeks of age or weighing less than 2 kg. Not recommended for Collie dogs, as safety has not been evaluated. Do not use in pregnant or lactating females without veterinary guidance. A minimum interval of 1 month should be observed between administrations. It may cause rare and mild side effects, such as diarrhea, vomiting, loss of appetite, salivation, and in very rare cases, tremors, ataxia and seizures, especially in dogs with a neurological history. Storage and care: Store in a cool, dry place, protected from light and out of reach of children and pets. Keep in the original packaging until use. Wash hands after handling and dispose of empty containers correctly. In summary, Defenza 400 mg is an effective and practical option for parasite control in medium to large dogs, with prolonged protection and ease of administration. It should always be used under veterinary guidance to ensure safety and efficacy.