 [ Symptoms ] how long does a sinus infection last  have had it since first of march   taken 10 days of strong antibiotic and then 10 days of strong musinex   getting better   will it eventually go away on it is own [ Disease ] the response to treatment is very individualized depending on the severity of the sinusitis the accuracy of the diagnosis the choicedosage of antibiotic and thepatient is response to those antibiotics one could remain symptomatic for a week or more since most sinus infections are viral the will eventually go away on their own the one is that require antibiotics may last a week or more