Hi dear , As per your query you have sore throat along with loss of voice . Yes sometimes there is loss of voice in strep throat . It happens usually when a person ignore sore throat and infection spread and infect the voice box or larynx also known as laryngitis . There is nothing to worry , your doctor has suggested you the right medicine . Do complete the course of the medicine with proper instructions given by your doctor . I would suggest you to :- Do warm saline gargles several times a day . it will be helpful with your sore throat as well as voice . Take proper rest and also give rest to your voice . Avoid eating or drinking clod and acidic . Hope your concern has been resolved. Dr. Harry Maheshwari