Antidepressants Side Effects: What’s Common, What’s Serious, and What to Do
Estimated reading time: 7 minutes
Key takeaways
- Antidepressants can cause side effects such as nausea, sleep changes, dizziness, dry mouth, sweating, weight changes, or sexual difficulties.
- Some side effects may ease as your body adjusts, while others can persist. Contact your prescriber if a symptom is troubling, severe, or interfering with daily life.
- New or worsening thoughts of suicide or self-harm and possible serotonin syndrome call for prompt attention.
- Stopping suddenly or missing doses can cause withdrawal symptoms. Don’t reduce your dose or stop without professional guidance.
Antidepressants can cause side effects such as nausea, sleep changes, dizziness, dry mouth, sweating, weight changes, or sexual difficulties. Which effects occur—and how strongly—depends on the medicine and the person taking it. Some may ease as your body adjusts, while others can persist. If a symptom is troubling, severe, or interfering with daily life, contact your prescriber rather than changing the dose or stopping the medication on your own. NHS: Antidepressants
That advice can be hard to follow when a medicine makes you feel worse before you feel better. Knowing which effects are possible, what needs urgent attention, and how side effects differ from withdrawal can help you decide what to do next.
Common antidepressant side effects
Side effects vary by medicine. Some people have none; others find that one or more symptoms affect their routine. Commonly reported effects include:
- Nausea or other stomach problems
- Headache
- Dry mouth
- Dizziness or drowsiness
- Sleep problems
- Sweating
- Weight changes
- Sexual difficulties
- Changes in mood or anxiety
These are possibilities, not a checklist that everyone will experience. Nor are they equally likely with every antidepressant. For example, selective serotonin reuptake inhibitors (SSRIs) may cause nausea, headache, dry mouth, tiredness, sleep problems, or sexual difficulties. Tricyclic antidepressants may cause dry mouth, blurred vision, constipation, difficulty urinating, lightheadedness, or drowsiness. NHS: Depression in adults—treatment
An SSRI is a type of antidepressant that affects serotonin signaling in the brain. A tricyclic antidepressant is another class of medicine, with a different profile of possible effects. The examples above don’t predict how an individual will respond, and a side effect associated with one medicine may not occur with another.
Sexual difficulties and weight changes deserve a conversation
Sexual problems can include changes in desire or difficulty reaching orgasm. Some people also notice weight changes. These effects can be sensitive to discuss, but they’re valid reasons to contact your prescriber. You don’t have to wait until a follow-up appointment if the problem is distressing or affecting your relationship or quality of life.
Sexual difficulties may continue for some people even after stopping an antidepressant, according to NHS guidance. If symptoms persist, raise them with a clinician rather than assuming they’re something you must tolerate. NHS: Antidepressants
How long do antidepressant side effects last?
There isn’t one timeline that applies to every medicine or person. Some side effects may lessen as your body adjusts, while others can persist. A symptom’s duration can also depend on the specific medicine, dose, and individual circumstances. Don’t assume that a difficult effect will definitely disappear—or that you have to endure it without support.
If you’ve recently started treatment or had a dose change, keep a short record of what you notice: when it began, how severe it is, and whether it affects sleep, work, driving, or everyday activities. That information can help your prescriber assess the problem. Contact them if an effect is persistent, distressing, or getting in the way of your usual activities. NHS: Antidepressants NHS: Fluoxetine
If you feel dizzy, drowsy, or have blurred vision, don’t drive, cycle, or operate machinery while you’re affected. NHS guidance gives this safety advice for fluoxetine; follow the information for your own medicine and ask a pharmacist or prescriber if you’re unsure. NHS: Fluoxetine
When to seek urgent help
Most side effects aren’t emergencies, but some changes call for prompt attention.
- New or worsening thoughts of suicide or self-harm: Contact a clinician promptly. If there’s immediate danger or you can’t stay safe, use emergency services. NHS: Antidepressants NHS: Depression in adults—treatment
- Possible serotonin syndrome: This is a potentially life-threatening reaction associated with medicines that affect serotonin. Warning signs can include a fast heartbeat, sweating, shaking, muscle twitching, confusion, or agitation. If you suspect a serious reaction, seek urgent medical assessment. The risk can increase when certain medicines are taken together, so ask a clinician or pharmacist to check combinations rather than trying to judge them yourself. NHS: Fluoxetine FDA prescribing information
When contacting a healthcare professional, explain which medicine you take, when you started it or changed the dose, what symptoms you’re experiencing, and whether you’ve added or stopped any other medicine or supplement. For urgent or severe symptoms, don’t wait for a routine appointment.
Side effects, withdrawal, or depression returning?
Symptoms after starting or changing an antidepressant may be side effects. Symptoms after a missed dose, dose reduction, or stopping may instead be withdrawal effects—or, in some cases, signs that depression is returning. These can be difficult to tell apart based on symptoms alone, because withdrawal can include emotional changes as well as physical ones.
Withdrawal symptoms may include dizziness, unusual sensations, irritability, anxiety, sleep problems, nausea, sweating, or palpitations. NICE says they can begin within days of reducing or stopping a medicine. They often resolve within one to two weeks, but can last longer—sometimes weeks or, occasionally, months—and can be severe, particularly after sudden stopping. NICE: Depression in adults—recommendations
Timing offers a clue, but it doesn’t prove what’s causing a symptom. NICE notes that withdrawal may resemble symptoms of depression, so a clinician may need to consider when symptoms began, the medicine and dose involved, and how they change over time. Don’t assume that every emotional change is a relapse, or that it is definitely withdrawal.
Don’t stop suddenly without advice
If side effects make you want to stop, contact your prescriber and explain what’s happening. Stopping suddenly or missing doses can cause withdrawal symptoms. If stopping is appropriate, NICE recommends a gradual, planned reduction tailored to the medicine, how long it has been taken, and the person’s symptoms. The plan should include monitoring for withdrawal and for returning depression symptoms. NICE: Depression in adults—recommendations
There’s no single tapering schedule that suits everyone. Don’t reduce your dose or follow someone else’s plan without professional guidance. If you’ve already missed doses or stopped, tell your prescriber what happened and when; they can advise you on the next step.
How to make a side-effect conversation more useful
A brief, specific report is often more helpful than saying only that the medicine “feels wrong.” Before contacting your prescriber or pharmacist, note:
- The symptom: For example, nausea, difficulty sleeping, or dizziness.
- The timing: When it started and whether it followed a new prescription or dose change.
- The impact: Whether it affects eating, sleep, work, driving, or other daily activities.
- Other changes: Any missed doses, new medicines, or supplements.
Ask which side effects are expected with your specific medicine, what to do if you miss a dose, which interactions to check, and when follow-up is planned. Review prescription and over-the-counter medicines and supplements with a professional. Some combinations can raise the risk of serious interactions, including serotonin syndrome. NHS: Depression in adults—treatment FDA prescribing information
Avoid making a change based only on a general list of side effects online. A symptom may have more than one cause, and a medicine that causes a problem for one person may be manageable—or have a different effect—for someone else. Your clinician can discuss options based on your symptoms and treatment.
Before starting an antidepressant
A short conversation before the first dose can help you know what to watch for. Ask the prescriber or pharmacist:
- Which side effects are most relevant to this medicine?
- What should I do if I miss a dose?
- Could it interact with my other medicines or supplements?
- When should I check in about how I’m responding?
Keep the medicine’s patient information available, and use a planned follow-up to discuss both benefits and unwanted effects. If a symptom becomes concerning before then, contact your care team sooner.
Antidepressants can have unwanted effects, but the experience is individual and different medicines have different profiles. If a symptom is hard to manage, write down when it began and how it affects you, then contact your prescriber or pharmacist before changing the dose. This article is for general education and doesn’t replace advice from a healthcare professional.
FAQ
What are common antidepressant side effects?
Commonly reported effects include nausea or other stomach problems, headache, dry mouth, dizziness or drowsiness, sleep problems, sweating, weight changes, sexual difficulties, and changes in mood or anxiety. Side effects vary by medicine, and some people have none.
How long can side effects last?
There isn’t one timeline that applies to every medicine or person. Some side effects may lessen as your body adjusts, while others can persist. Contact your prescriber if an effect is persistent, distressing, or getting in the way of your usual activities.
When should I seek urgent help?
New or worsening thoughts of suicide or self-harm and possible serotonin syndrome call for prompt attention. If there’s immediate danger or you can’t stay safe, use emergency services. For urgent or severe symptoms, don’t wait for a routine appointment.
Should I stop taking my antidepressant?
If side effects make you want to stop, contact your prescriber and explain what’s happening. Stopping suddenly or missing doses can cause withdrawal symptoms. Don’t reduce your dose or follow someone else’s plan without professional guidance.
