Aloha! You're speaking with Dr. Michael Salkin
Here's a synopsis on the efficacy of imidacloprid (Advocate) when addressing lice:
"In a clinical field study, imidacloprid (Advocate/Advantage) was tested in dogs with natural infestation of both sucking and chewing lice 1
. Dogs that tested positive with lice were treated using 10% imidacloprid spot-on at a dosage of 10 mg/ kg b. w.
The study included 27 dogs from a large variety of breeds, with light (13 dogs), moderate (8 dogs) or high (6 dogs) louse infestations. In addition to the parasitological examinations, dermatological lesions were examined at 24 hours and 2, 4 and 6 weeks after treatment. Imidacloprid provided a very high level of efficacy, with a 24-hour post treatment knock-down effect. All dogs were free of lice for up to 6 weeks following treatment.
A registered claim for the treatment of both biting and sucking lice exists in Australia for Advantage. The performance of Advocate against sucking lice would be expected to be identical, as there is no variation in the concentration or dosage of imidacloprid between these two formulations.
European studies demonstrate that Advocate offers a high level of lice control. A marked reduction of 89.9% one day after treatment and an overall efficacy of 99.7% at day 28 has been proven.
The success of a single treatment in the strong indication in slowly developing biting lice shows the plausibility of long-term efficacy of Advocate.
To answer you directly, then, 100% of control isn't expected by tomorrow but is expected within a month. Please respond with further questions or concerns if you wish. Be sure to clean any bedding, grooming tools, and your environment at least once. Most any commercial detergent cleanser will suffic.