SSRIs (selective serotonin reuptake inhibitors) are among the most commonly prescribed medications in the world, used to treat depression, anxiety, OCD, PTSD, and more. Despite being generally well-tolerated, SSRIs interact with a surprisingly wide range of other medications — including many people buy over the counter without a second thought.
This guide covers the most important SSRI interactions, why they occur, and what to do about them.
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Check interactions now →The interactions in this guide apply to the entire SSRI class, though some are more pronounced with specific drugs:
Never take an SSRI with a monoamine oxidase inhibitor (MAOI). This combination can cause serotonin syndrome — a potentially life-threatening condition from excessive serotonin activity in the body.
MAOIs include phenelzine (Nardil), tranylcypromine (Parnate), isocarboxazid (Marplan), and selegiline (Emsam). Even the antibiotic linezolid has MAOI properties. You must wait at least 14 days after stopping an MAOI before starting an SSRI — and vice versa (with fluoxetine specifically, wait 5 weeks after stopping it before taking an MAOI, due to its long half-life).
SSRIs inhibit platelet function by reducing the serotonin that platelets normally use to help form clots. Combined with anticoagulants like warfarin, this significantly increases bleeding risk. People on warfarin who start an SSRI need more frequent INR monitoring. The interaction is also relevant with newer blood thinners like apixaban (Eliquis) and rivaroxaban (Xarelto).
NSAIDs combined with SSRIs is one of the most commonly overlooked drug interactions. Both reduce platelet function through different mechanisms, making gastrointestinal bleeding significantly more likely. Studies suggest the combination increases GI bleeding risk by 3–15 times compared to either drug alone. If you need pain relief while on an SSRI, acetaminophen (Tylenol) is a much safer choice.
Triptans such as sumatriptan (Imitrex), rizatriptan (Maxalt), and others are used for migraines. The FDA has warned about combining them with SSRIs due to a theoretical risk of serotonin syndrome. In practice, the interaction is considered relatively low risk by many migraine specialists, but it should be discussed with your doctor — particularly at higher doses.
St. John's Wort is a popular herbal supplement used for mild depression. Combining it with an SSRI can cause serotonin syndrome. Despite being "natural," St. John's Wort has real pharmacological effects and is a meaningful drug interaction risk. It also affects liver enzymes in ways that can alter the blood levels of many other medications.
Tramadol (a pain medication) increases serotonin activity. Combined with an SSRI, this raises the risk of serotonin syndrome. SSRIs (particularly fluoxetine and paroxetine) also reduce the body's ability to convert tramadol to its active form, potentially reducing pain relief. This is a complex interaction — always disclose SSRI use to any doctor prescribing tramadol.
| Medication / Substance | Risk | What Happens |
|---|---|---|
| Lithium | Moderate–High | Increased serotonin syndrome risk; requires monitoring |
| Alcohol | Moderate | Worsens depression, increases sedation, reduces SSRI effectiveness |
| Certain antifungals (fluconazole) | Moderate | Can raise SSRI blood levels by blocking metabolism |
| Antipsychotics | Moderate | Some SSRIs raise antipsychotic blood levels; QT interval concerns |
| Certain heart medications | Moderate | QT prolongation risk with some combinations |
| Dextromethorphan (DXM in cough syrup) | Low–Moderate | Can increase serotonin activity; avoid large amounts |
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Try MedCheck free →It's best to avoid regular ibuprofen use with sertraline (Zoloft) or any SSRI. The combination significantly increases gastrointestinal bleeding risk. For occasional pain relief, acetaminophen (Tylenol) at normal doses is a much safer choice. If you need anti-inflammatory medication regularly, talk to your doctor about alternatives.
Alcohol and SSRIs are generally not recommended together. Alcohol is a depressant that can worsen the very symptoms SSRIs treat, and it increases sedation and impaired judgment. Occasional light drinking may be acceptable for some people, but regular drinking significantly undermines antidepressant treatment. Discuss this honestly with your doctor.
Low-dose melatonin (0.5–3mg) is generally considered relatively safe with SSRIs for most people. However, high-dose melatonin and some SSRIs may interact at the serotonin level. It's worth mentioning to your doctor. See our detailed guide on melatonin and antidepressants.
It depends on the specific SSRI. Most SSRIs clear your system within a few days to two weeks. Fluoxetine (Prozac) is the exception — its active metabolite has a half-life of up to 6 days, meaning it takes 4–6 weeks to fully clear. This is why you must wait 5 weeks after stopping Prozac before starting an MAOI.