Zoloft Side Effects First Week: What to Expect

By Irmanie Hemphill, MD, FAAFP
Medically reviewed
July 29, 2021

Anxiety and depression are the most common mental illnesses in the United States. Anxiety alone affects 40 million adults each year.

These disorders are highly treatable, but only 36.9% of those suffering with anxiety receive treatment. Medications like Zoloft can help treat anxiety and depression.

Though medications like these can be highly effective, some people may experience side effects.

In this article, I’ll describe what Zoloft is, the conditions it’s used to treat, how to start taking it, and how long the drug generally takes to work. I’ll also cover the possible short- and long-term side effects of taking the medication.

Finally, I’ll explain the risks of taking Zoloft, when it’s important to reach out to your provider about side effects, and how to safely stop taking the medication. 

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Starting Zoloft

Zoloft is an FDA-approved brand name of the generic antidepressant medication called sertraline. It belongs to a class of drugs called selective serotonin reuptake inhibitors, or SSRIs.

Other SSRI medications include fluoxetine (Prozac), paroxetine (Paxil), fluvoxamine (Luvox), citalopram (Celexa), and escitalopram (Lexapro).

These types of medications work by increasing the amount of the chemical serotonin available in the brain and body. They are only available with your doctor’s prescription.

Zoloft is most commonly prescribed in the treatment of the following health conditions:

If your doctor prescribes Zoloft, be sure to take the medication only as directed by your doctor. Don’t take more or less of it than prescribed and don’t take it for a longer or shorter period of time than recommended by your doctor.

The standard dose of Zoloft will range between 25-100mg daily, depending on your condition, health, symptom severity, and other personal health factors. As with most medications, be sure to follow the exact dosage prescribed by your doctor.

Once you’ve been prescribed Zoloft, it may take four to eight weeks for the medication to start taking effect. But according to the National Alliance on Mental Illness, your sleep, energy, or appetite may start to show signs of improvement in the first one to two weeks of taking Zoloft.

If this happens, it may be a sign that the medication is working for you. 

What Are the Possible Side Effects for the First Week?

Like most antidepressant medications, Zoloft can produce side effects. The most common side effects to expect within the first week of starting the medication are:

In most cases, these early side effects will clear up within the first one to two weeks of starting the medication.

However, it is possible to experience some of these side effects intermittently as you continue to take the medication, especially if your healthcare provider increases your dose. 

Serious Side Effects

Though rare, Zoloft can cause more serious side effects, including: 

  • Low sodium blood levels: Symptoms of low sodium levels can include headache, weakness, or difficulty concentrating or remembering.
  • Serotonin syndrome: Signs of serotonin syndrome can include shivering, diarrhea, confusion, severe muscle tightness, fever, and seizures.
  • Eye pain or angle-closure glaucoma: Symptoms of this condition include changes in vision, swelling or redness in or around the eye, and general eye pain.
  • Increased risk of bleeding: Combining Zoloft or another SSRI with aspirin, nonsteroidal anti-inflammatory drugs, NSAIDs (like ibuprofen), or blood thinners like warfarin can increase the risk of bleeding, including gum bleeding, nose bleeding, and gastrointestinal bleeding.
  • Manic episodes: For people with undiagnosed bipolar disorder, Zoloft may cause an increase in manic episodes.
  • Sexual side effects: Zoloft can cause some sexual side effects, including delayed ejaculation.
  • Suicidal thoughts: Zoloft may increase the risk of suicidality, especially in children, adolescents, and young adults.

If you experience any of the above symptoms, reach out to your doctor as soon as possible. 

What If You Miss a Dose on Zoloft?

If you miss a dose while taking Zoloft, take it as soon as you can. However, if it’s almost time for your next dose, skip the missed dose and stick to your regular dosing schedule. Never take a double dose of Zoloft.

Safety and Risks

When used as directed, there are no known problems associated with long term use of Zoloft.

However, Zoloft may not be right for everyone. Talk with your doctor if you’re pregnant or plan to become pregnant, if you’ve been diagnosed with bipolar disorder, or if you take monoamine oxidase inhibitors (MAOIs) or anticoagulants (like warfarin).

Before starting this or any other medication, it’s a good idea to let your doctor know of all the prescription and over-the-counter (OTC) medications you’re taking—as well as any supplements or herbal remedies—to avoid any adverse drug interactions.

Overdose Information

Overdosing on Zoloft can cause serious health concerns. Call your provider or 911 to seek immediate medical care if you think you may have overdosed on the medication.

Taking two or more doses of Zoloft can cause serious side effects, including:

  • Nausea
  • Vomiting
  • Dizziness
  • Agitation
  • Confusion
  • Fever
  • Fainting
  • Hallucinations
  • Changes in blood pressure
  • Rapid heartbeat
  • Tremors 
  • Seizures
  • Serotonin syndrome 

When to Talk to a Doctor About Side Effects

When starting any medication, it’s helpful to know what to expect. If you’re starting Zoloft, experiencing some side effects within the first two weeks of starting the medication is completely normal. 

However, the rare but more serious side effects mentioned throughout this article should warrant medical attention.

If you experience any of the serious side effects mentioned, including suicidal thoughts, worsening depression and anxiety, manic episodes, hallucinations, and more, reach out to your doctor immediately. 

When taken as directed, Zoloft can be effective in treating both depression and anxiety. But if Zoloft doesn’t work for you, there are other SSRIs or medications that may be more effective.

If you’re still experiencing mild side effects after two weeks of starting the medication, or if you’re not experiencing an improvement in your condition, talk with your doctor to learn about popular alternatives to Zoloft and your other treatment options.

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Stopping Zoloft

Making the decision to stop taking Zoloft should be considered thoughtfully and with the support of your doctor and/or therapist.

If you decide to stop taking the medication, talk with your doctor about the steps you can take to minimize or avoid symptoms that can occur when you stop taking the medication abruptly.

In many cases, withdrawal symptoms can mimic the symptoms of major depressive disorder. Other symptoms can include:

  • Nausea
  • Vomiting
  • Cramps
  • Diarrhea
  • Loss of appetite
  • Lightheadedness
  • Sleep changes (including insomnia and nightmares)
  • Tremors
  • Restless legs
  • Difficulty coordinating speech and chewing movements
  • Hypersensitivity to sounds or sensations

Tapering your dosage at the guidance of your physician can help minimize or eliminate the symptoms of discontinuation.

Follow your doctor’s medical advice on the recommended approach if and when you decide to stop taking Zoloft.

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K Health articles are all written and reviewed by MDs, PhDs, NPs, or PharmDs and are for informational purposes only. This information does not constitute and should not be relied on for professional medical advice. Always talk to your doctor about the risks and benefits of any treatment.

Irmanie Hemphill, MD, FAAFP

Dr. Hemphill is an award winning primary care physician with an MD from Florida State University College of Medicine. She completed her residency at Halifax Medical Center.