Citalopram interacts with a surprisingly long list of medications, supplements, and common substances. The most dangerous combinations involve anything that raises serotonin levels alongside citalopram, which can trigger a potentially life-threatening condition called serotonin syndrome. But the risks don’t stop there: certain painkillers increase your bleeding risk, some drugs can cause dangerous heart rhythm changes, and even everyday choices like alcohol and herbal supplements can cause problems.
MAO Inhibitors: The Most Dangerous Combination
The single most critical interaction is between citalopram and a class of antidepressants called MAO inhibitors (MAOIs), which include phenelzine, isocarboxazid, and tranylcypromine. Combining these two types of medication dramatically increases the likelihood of serotonin syndrome, a condition where excess serotonin floods the brain and body. Symptoms include dangerously high body temperature, rapid heart rate, muscle rigidity, agitation, and seizures. This combination should never be used.
Even switching between the two requires careful timing. If you’re stopping citalopram before starting an MAOI, you need a minimum two-week washout period. If you’re going the other direction, stopping an irreversible MAOI before starting citalopram, a 14-day drug-free period is necessary to let the MAOI fully clear your system. These waiting periods exist because the drugs linger in your body long after you stop taking them.
Other Medications That Raise Serotonin
MAOIs aren’t the only drugs that can push serotonin to dangerous levels when paired with citalopram. Tramadol, a commonly prescribed painkiller, carries a dual risk. It both raises serotonin and lowers the seizure threshold, so combining it with citalopram increases the chance of both serotonin syndrome and seizures. If you take tramadol for pain, this is a combination that typically requires a therapy change.
Triptans, the go-to medications for treating migraines (such as sumatriptan and rizatriptan), also act on serotonin pathways. The FDA issued an alert in 2006 warning that combining triptans with SSRIs like citalopram could cause serotonin syndrome. In practice, the risk appears to be quite low. A review of reported cases found that triptans “might rarely precipitate serotonin syndrome” when used with SSRIs, and the authors concluded the evidence didn’t support changing how the two are prescribed together. Still, the risk is highest when you first start citalopram or increase your dose, so it’s worth being aware of the symptoms: confusion, rapid heartbeat, sweating, muscle twitching, and high fever.
St. John’s Wort
St. John’s Wort is an herbal supplement widely used for mild depression, and it’s one of the most important things to avoid while taking citalopram. It works in a strikingly similar way, blocking the reabsorption of serotonin in the brain. Combining the two can dangerously elevate serotonin levels.
The interaction is actually worse for citalopram than for some other antidepressants. St. John’s Wort affects the same liver enzyme (CYP2C19) that breaks down citalopram, meaning it can alter how much citalopram stays active in your bloodstream on top of the serotonin-boosting effect. This double interaction makes the combination particularly risky. Because St. John’s Wort is sold over the counter, people sometimes don’t think of it as a “real” medication, but in this case it absolutely is one.
Common Pain Relievers and NSAIDs
Ibuprofen, aspirin, naproxen, and other nonsteroidal anti-inflammatory drugs (NSAIDs) are worth paying attention to if you take citalopram. SSRIs on their own modestly increase the risk of upper gastrointestinal bleeding, roughly doubling it compared to people not taking an SSRI. But when you add an NSAID on top, the risk jumps significantly. A large meta-analysis covering more than a million people found that combining SSRIs with NSAIDs increased the risk of upper GI bleeding by roughly four to ten times, depending on the study.
This doesn’t mean you can never take ibuprofen for a headache, but regular or heavy use of NSAIDs alongside citalopram is a real concern. The risk is highest in people who already have risk factors for GI bleeding, such as a history of ulcers or older age. If you need frequent pain relief, acetaminophen (Tylenol) is generally a safer option, though it’s worth confirming with your pharmacist.
Drugs That Affect Heart Rhythm
Citalopram has a unique concern among antidepressants: at higher doses, it can cause a heart rhythm abnormality called QT prolongation, which in rare cases leads to a dangerous irregular heartbeat. This is why the FDA capped the maximum dose at 40 mg per day in 2011, and lowered it further to 20 mg per day for people over 60, those with liver problems, and those taking certain other medications.
One specific medication to watch is cimetidine (sold as Tagamet), an older heartburn drug. Cimetidine inhibits the liver enzyme that processes citalopram, causing citalopram levels to build up in your blood. Higher blood levels mean a greater effect on heart rhythm. Other drugs that independently prolong the QT interval, including certain antiarrhythmics, some antibiotics, and some antipsychotics, compound this risk when taken alongside citalopram. If you’re on any heart medication or have been told you have a long QT interval, this is especially relevant.
Alcohol
Alcohol amplifies citalopram’s effects on the nervous system. You can expect increased dizziness, drowsiness, and difficulty concentrating if you drink while taking it. Beyond those immediate effects, alcohol can impair your thinking and judgment more than either substance would alone. This is particularly relevant for driving or any activity that requires you to be alert. The general recommendation is to avoid or significantly limit alcohol while on citalopram.
There’s also a less obvious concern. Alcohol is a depressant, and since citalopram is prescribed to treat depression and anxiety, regular drinking can work against the medication’s purpose. People who drink heavily while on citalopram often find the medication less effective.
Recognizing Serotonin Syndrome
Because so many of these interactions involve the risk of serotonin syndrome, knowing the warning signs matters. Symptoms typically develop within hours of taking a new serotonin-boosting substance or increasing a dose. Early signs include agitation, restlessness, and diarrhea. More severe cases involve rapid heart rate, high blood pressure, muscle twitching or rigidity, heavy sweating, and a high fever. In its most extreme form, serotonin syndrome can cause seizures and be life-threatening. If you develop these symptoms after starting a new medication or supplement alongside citalopram, it requires immediate medical attention.