They may even worsen undiagnosed medical disorders that are further aggravated by the stress of travel. Most drugs used for this purpose are short acting, with a peak effect lasting only several hours. For longer trips, it may not be worthwhile to sedate your pet, though it may help it through the first part of the trip. Drugs should probably be reserved for pets that suffer from extreme fear or anxiety during travel and should be used only at your veterinarian's recommendation. The risk of tranquilizing your pet must be weighed against the benefits.
Some pets become more anxious when a tranquilizer begins to take effect.
An unusual reaction to tranquilizers can make a pet agitated and excitable. It may help to do a 'test run' by giving a dose of the medication a few days before travel so you can observe its effects on your pet. Take frequent short trips with your cat. Place your cat in a carrier with a soft blanket so it can feel more secure. Cats are more confident and comforted in a confined area.