24-48 hours depends on whats wrong.
how long does it take to decrease fever after starting antibiotics. my husband was diagnosed with sinusitis and early pneumonia. he was given a shot of rocephin and then sent home with 7 days of levoquin once daily. he took his first dose of levoquin at about 7 pm last night. he is still running fevers of 100. 4-100. 8. how long should it take for his fever to go away? he is also having head aches and sore throat unrelieved by motrin 400 mg or tylonol 650 mg. how long will it take the antibiotics to relieve these symptoms as well?