Now the answers for your questions: First of all, the worm load between animals and human beings vary, so do the type of worms. Secondly deworming medicines are dosed depending upon the body weight of the patient. You may far outweigh your dog! Hence the dosage may turn inadequate to flush the worms from your body. Thirdly, the interval has to be spaced apart depending upon the worm load, type of infection, and the response of the body to the treatment; sometimes a body may respond with allergy rather than shedding the worms! Beware; any side effect arising out of lack of medical supervision may be life threatening. While deciding to administer a medicine, the benefits should far outweigh the risks, and that should be a decision taken by your doctor. Note that Praziquantel is not licensed for use in human beings in the UK! Lastly, the aforementioned ingredients are given to different types of worm infestations. Usually a human being may not have all those types of worms in his/her body and may not need all of those ingredients to treat only a particular type of worm.