What Are the Side Effects of Capstar Flea Medicine?

Capstar quickly provides most dogs and cats with relief from fleas. This oral medication begins working within 30 minutes upon administration to kill the pests on canines and felines. Many pet owners are pleased with the results that Capstar provides and use it regularly to control fleas in their animals. While Capstar is generally safe, it has the potential for certain side effects.

  1. Scratching

    • According to the Pet Place website, Capstar can cause a pet to scratch itself excessively. This type of behavior typically occurs as the medication begins to work and the fleas start to die. The dog or cat will scratch as a result of the dying fleas, not the medication. The excessive scratching is typically temporary and will likely resolve on its own. If the pet causes injury to itself as a result of the scratching, such as irritation or wounds, consult your veterinarian for further treatment.

    Excessive Grooming

    • Some cats may excessively groom themselves after receiving Capstar treatment, states the Drugs website. The grooming behavior is likely a result of the fleas dying, which can cause the cat to feel rather itchy. The cat may also groom itself in an effort to remove the dead fleas from its body. To assist the cat, you can give it a bath to wash off the fleas. Watch your cat for signs of tapeworms after it has fleas, as tapeworms are often caused by ingesting fleas. Signs of tapeworms include seeing rice-like segments around your cat's anus or its bedding areas. These are actually tapeworm segments that have broken away from the tapeworm in the cat's intestine and have crawled out through its anus. Your cat's veterinarian can provide treatment for the elimination of the tapeworms.

    Abnormal Behavior

    • Some cats will exhibit abnormal behavior as a result of Capstar. Although it is rare, some cats will pant excessively, become hyper or start to vocalize more than usual. This abnormal behavior is potentially a cause for concern. If your cat begins to show either of these behaviors, contact its veterinarian immediately.