Sertraline Side Effects: What to Expect and When to Call Your Doctor

Starting a new antidepressant can feel uncertain. Sertraline (Zoloft) is well-studied and used by millions of people — but it does cause side effects in many patients, especially in the first few weeks. Knowing what to expect, what usually goes away on its own, and what warrants a call to your doctor can make the difference between a successful treatment and an unnecessary discontinuation.

Boxed Warning: Suicidal Thoughts in Young Patients

The FDA requires all antidepressants, including sertraline, to carry a boxed warning (the strongest FDA warning). The warning states that antidepressants increase the risk of suicidal thinking and behavior in children, adolescents, and young adults ages 18–24 with major depressive disorder and other psychiatric disorders.

Short-term studies have not shown an increase in suicidality with antidepressants in patients older than 24 years, and there was a reduction in suicidality in patients over 65. If you or someone in your care is under 25, discuss this risk with your prescriber and ensure close monitoring during the first few weeks of treatment.

Common Side Effects (Usually Temporary)

Most sertraline side effects are most pronounced in the first 1–4 weeks of treatment and improve as your body adjusts. Common side effects occurring in 5% or more of patients include:

• Nausea: The most common early side effect. Takes 1–4 weeks to typically resolve. Taking sertraline with food can reduce nausea.
• Diarrhea: Often occurs early in treatment; tends to improve. Stay well hydrated.
• Headache: Common in the first few weeks. Usually responds to OTC pain relievers (check with your doctor about using NSAIDs with sertraline).
• Insomnia or sleep changes: Some patients experience difficulty sleeping, particularly if they take sertraline at night. Switching to morning dosing may help.
• Dry mouth: Drinking water frequently and chewing sugar-free gum can help.
• Increased sweating: Night sweats and daytime sweating are reported by some patients. Usually mild.
• Tremor: Mild shakiness, especially of the hands. More common at higher doses.
• Decreased appetite: Some patients notice reduced appetite. Sertraline is notably less likely to cause weight gain than many other antidepressants.

Sexual Side Effects

Sexual side effects are among the most common reasons patients discontinue sertraline. These include:

• Decreased libido (reduced sex drive)
• Delayed orgasm or difficulty achieving orgasm
• Inability to ejaculate in males (ejaculatory dysfunction)

These effects are dose-dependent — higher doses are more likely to cause them. In rare cases, sexual dysfunction can persist even after sertraline is discontinued (post-SSRI sexual dysfunction, or PSSD). Talk to your doctor about this risk and management strategies if sexual side effects occur.

Serious Side Effects: When to Call Your Doctor Immediately

Seek immediate medical attention or call 911 if you experience any of these:

• Signs of serotonin syndrome: Agitation, confusion, rapid heart rate, high fever, muscle twitching/rigidity, sweating, diarrhea, loss of coordination. This is a medical emergency. Risk is highest when sertraline is combined with other serotonergic drugs.
• Unusual bleeding: Sertraline can increase bleeding risk, especially when combined with NSAIDs or blood thinners. Watch for unusual bruising, blood in stool, or prolonged bleeding from cuts.
• Hyponatremia (low sodium): Symptoms include headache, difficulty concentrating, memory impairment, weakness, and in severe cases seizures. More common in elderly patients on diuretics.
• Manic episode: Sudden euphoria, decreased need for sleep, racing thoughts, impulsive behavior. Sertraline can trigger mania in patients with undiagnosed bipolar disorder.
• Severe allergic reaction: Rash, hives, swelling of face/lips/throat, difficulty breathing.
• New or worsening suicidal thoughts (especially in patients under 25).

Discontinuation Syndrome: What Happens If You Stop Suddenly

Do not stop sertraline abruptly. Stopping without a taper can cause discontinuation syndrome — a collection of withdrawal-like symptoms including dizziness, nausea, flu-like symptoms, irritability, agitation, and electric shock sensations ("brain zaps"). These symptoms typically appear within 1–3 days of stopping and can last 1–2 weeks or longer in some patients.

Always taper sertraline gradually under your doctor's guidance — typically over 2–4 weeks or longer, depending on your dose and duration of treatment.

See also: Sertraline Drug Interactions: What to Avoid and What to Tell Your Doctor.

Also: What Is Sertraline? Uses, Dosage, and What You Need to Know in 2026.