Zoloft Side Effects. Common side effects of Zoloft include: insomnia, loose stools, dizziness, drowsiness, tremor, fatigue, diarrhea, dyspepsia, nausea, headache, paresthesia, diaphoresis, decreased libido, delayed ejaculation, ejaculation failure, xerostomia, and anorexia. Other side effects include: abdominal pain, agitation, pain, vomiting, hypouricemia, anxiety, and malaise. See below for a comprehensive list of adverse effects.