Weight gain is a side effect of many antidepressants, including (Sildenafil Fluoxetine). A study published in 2014 in the journal JAMA Psychiatry found that people taking fluoxetine and other SSRIs gained one to two pounds over the course of a year; weight gain varied, depending on the SSRI used. If you’re concerned about weight gain while taking Sildenafil Fluoxetine, talk with your doctor.