Over the years veterinarians have been treating itchy dogs with allergies with an increasing number of drugs that are aimed at decreasing the dog’s constant itching and licking. These drugs usually worked when you gave them, but of course stopped working once you stopped them, they simply treated the symptom not the cause. There are four generations of these drugs. The first of these drugs were the corticosteroids(cortisone) usually, prednisone pills. This was and is still used because it’s effective at stopping the itch and was very inexpensive. Unfortunately this drug has lots of side effects.

The second generation of anti itch drug was Atopica (cyclosporine). This drug was effective but was very expensive for long term use, but did have fewer side effects then prednisone.

The third generation of anti -itch drugs and the most widely used are Apoquel and Zenrelia. These drugs are very targeted to inhibit the enzyme, JAK1 which produces Interleukin 31, which turns out to be the molecule responsible for causing most of the itch sensation. Because these drugs are very targeted there are very few side effects, making them very safe for long term use. Although cheaper than Atopica they are not inexpensive.

The fourth generation and the newest one, is not a pill but a monthly injection. The drug is Cytopoint, a monoclonal antibody that when injected into the body attaches to Interleukin 31, the itch molecule and inactivates it for a month. This drug is so very targeted that there are virtually no side effects. This drug is expensive.

Although these drugs are very effective at reducing itching and licking, they work best when the itch is due to environmental allergies like pollen, mold spores and house dust mites. They may work less effectively when the itch is due to food allergies or infections. This is why it is very important to rule out these other causes of itch first before using these anti itch medications. Environmental allergies can respond well to allergy immunotherapy (allergy shots), but allergy testing is required to determine what allergens to put into the allergy shots. This is best done by a veterinary dermatologist.