SSRI Side Effects: What to Expect
The common side effects of SSRI antidepressants, the serious ones to watch for, and what to do about each.
Clinically reviewed by Joseph Lavoie, MSN, APRN, PMHNP-BC · Last reviewed
The short answer
Common SSRI side effects include nausea, headache, upset stomach, trouble sleeping or drowsiness, sweating, feeling jittery, and sexual side effects such as lower desire or delayed orgasm. Many of the early ones fade within the first few weeks. SSRIs carry an FDA boxed warning about increased suicidal thoughts and behaviors in children, teens and young adults under 25, so anyone starting one should be watched closely at first.
What SSRIs are
Selective serotonin reuptake inhibitors (SSRIs) are the most widely prescribed antidepressants. They are used for depression, anxiety disorders, panic disorder, OCD, PTSD and other conditions. They work by increasing the amount of serotonin available between nerve cells in the brain. SSRIs available in the United States include citalopram, escitalopram, fluoxetine, fluvoxamine, paroxetine and sertraline.
Each SSRI has a slightly different side effect profile, and people respond differently to the same drug. A side effect that bothers one person may never show up for another. This page is general information. The patient information that comes with your prescription, and your prescriber, are the final word for your medication.
Side effects are one of the main reasons people stop antidepressants early, often before the medication has had a chance to help. Knowing what to expect, and having a prescriber who checks in, makes it much easier to stick with a plan or change it safely.
Common side effects
These are the side effects people report most often, based on MedlinePlus drug information and FDA labeling:
| Side effect | When it tends to show up | What often helps |
|---|---|---|
| Nausea, upset stomach, diarrhea | First 1 to 2 weeks | Taking it with food; usually eases on its own |
| Headache | Early | Often fades; ask before adding pain relievers |
| Trouble sleeping or vivid dreams | Early, sometimes ongoing | Ask whether morning dosing makes sense for your medication |
| Drowsiness or tiredness | Early, sometimes ongoing | Ask whether evening dosing makes sense; avoid driving until you know how it affects you |
| Jittery, restless or more anxious | First days to weeks | Tell your prescriber; plans often start low for this reason |
| Sweating | Can persist | Mention it; it is common and sometimes manageable |
| Sexual side effects | Can start any time and persist | Raise it; there are several options |
| Weight or appetite change | Over months | Track it and discuss at follow-ups |
Do not change when or how you take a medication without checking with your prescriber or pharmacist first.
The FDA boxed warning on suicidal thoughts
All antidepressants, including SSRIs, carry the FDA’s strongest warning, called a boxed warning. In short-term studies, antidepressants increased the risk of suicidal thinking and behavior in children, teenagers and young adults under age 25, compared with a placebo. This risk was not seen in adults over 24, and adults 65 and older had a lower risk.
That does not mean the medication should be avoided. Untreated depression also carries a serious risk of suicide. It means that anyone starting an antidepressant, or changing the dose, should be watched closely, especially in the first few months. Family members should watch for:
- New or worse depression, anxiety or panic attacks
- Talk of suicide or self-harm, or acting on those thoughts
- Agitation, restlessness, anger or aggression
- Trouble sleeping, or acting on dangerous impulses
- Extreme increase in energy, talking or activity (possible mania)
Report any of these to the prescriber right away. If someone is in danger, call or text 988, or call 911.
Serious side effects: call your prescriber or get help
These are uncommon, but you should know them:
- Serotonin syndrome. Agitation, confusion, fast heartbeat, high temperature, heavy sweating, shivering, muscle twitching or stiffness, and diarrhea. The risk goes up when SSRIs are combined with other drugs that raise serotonin, such as some migraine medications, tramadol or St. John’s wort. Get emergency care.
- Bleeding. SSRIs can increase the risk of bleeding, especially with aspirin, ibuprofen, naproxen or blood thinners. Watch for unusual bruising, nosebleeds or black stools.
- Low sodium. More likely in older adults. Signs include headache, confusion, weakness and unsteadiness.
- Mania. In people with bipolar disorder, an antidepressant alone can trigger a manic episode. Tell your prescriber about any family history of bipolar disorder.
- Eye pain or vision changes. SSRIs can trigger a type of glaucoma in people whose eyes are at risk.
- Allergic reaction. Rash, hives, or swelling of the face or throat needs emergency care.
Tell every prescriber, dentist and pharmacist you see that you take an SSRI, and mention all supplements and over-the-counter medicines.
Stopping an SSRI
Stopping an SSRI suddenly can cause discontinuation symptoms: dizziness, flu-like feelings, nausea, irritability, trouble sleeping, and brief electric-shock feelings some people call “brain zaps.” These are not the same as addiction, but they can be unpleasant. They are more likely with SSRIs that leave the body quickly.
If you want to stop, or side effects are getting in the way, talk with your prescriber. A gradual taper, a different SSRI or another kind of treatment may be options. SSRIs often take several weeks to work fully, so it can help to give early side effects some time unless they are severe; see how long antidepressants take to work.
At Journey Psychiatric Care, Joseph Lavoie, PMHNP-BC, a board-certified psychiatric nurse practitioner, talks through side effects before anything is started and checks on them at each follow-up. See medication management, and the pages on depression and anxiety treatment.
Frequently asked questions
How long do SSRI side effects last?
Many early side effects, such as nausea, headache and jitteriness, ease within the first one to two weeks as your body adjusts. Some, such as sexual side effects or sweating, can continue as long as you take the medication. If a side effect does not improve, tell your prescriber.
Do SSRIs cause weight gain?
Some people gain weight over months on an SSRI, while others do not, and it varies by medication. Changes in mood can also change appetite. Keep track and discuss it at your follow-up visits rather than stopping on your own.
Can SSRIs make anxiety worse at first?
Yes. Some people feel more jittery, restless or anxious in the first days to weeks. This is one reason prescribers often start low. Tell your prescriber if it happens, and get help right away if it comes with thoughts of self-harm.
What helps with sexual side effects from SSRIs?
Options include waiting to see if it improves, changing the dose, switching to a different medication, or adding a treatment for the side effect. Your prescriber can only help if you bring it up, and it is a very common conversation.
Can I drink alcohol on an SSRI?
Alcohol can worsen depression and anxiety and add to drowsiness. Many prescribers advise avoiding it or limiting it, especially early on. Ask your prescriber what is safe for you.
Do SSRIs change your personality?
SSRIs are not meant to change who you are. Some people notice feeling emotionally flat or less like themselves, which is a known side effect worth reporting. Often a dose change or a different medication helps.
Are SSRIs safe during pregnancy?
It depends on the person and the medication. Untreated depression in pregnancy also has risks. If you are pregnant, planning a pregnancy or breastfeeding, talk with your prescriber and obstetric provider before starting, stopping or changing an SSRI.
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