The duration of the administration of any medication depends on the condition of the pets and the speed of the ailments. It is advisable that Iverhart Plus chewable tablets are given once in thirty days. You can note the fact that the initial dose after the exposure to the mosquitos for the first time should be given within a period of one month. The monthly administration of the chewable tablets ensures that the vectors or the mosquitos carrying the larvae of the infestations are treated at the source. As a pet parent, you should look out for signs which can let you know about any worm infestation in your pet. The symptoms that should keep an eye for can include weight loss which is accompanied by an increase or decrease in appetite, loss of hair or dulling of the coat with inflammations and skin irritations, distended or pot-bellied abdomen, chronic coughing, lethargy, diarrhea, vomiting, and soft stools. If you notice any of the above symptoms you should consult your pet's veterinarian to help you with the administration of the right medication and pursue the necessary steps to help your pet get rid of the worm infestations.