contraindication
12 interactions related to contraindication
sertraline + st. john's wort
Sertraline is an SSRI that blocks serotonin reuptake, and St. John's wort independently raises central serotonin through constituents such as hyperforin and hypericin. Combining them can trigger serotonin syndrome, a potentially life-threatening reaction marked by altered mental status, autonomic instability, and neuromuscular hyperactivity. St. John's wort also induces CYP3A4 and CYP2C19, which can lower sertraline levels and undermine treatment.
duloxetine + st. john's wort
Duloxetine and St. John's wort both increase serotonergic activity, and combining them can raise serotonin to levels associated with serotonin syndrome.
fluoxetine + st. john's wort
Fluoxetine and St. John's wort both increase serotonin activity, and combining them can add to the same effect and contribute to serotonin syndrome.
metronidazole + alcohol
Metronidazole is traditionally said to cause a disulfiram-like reaction with alcohol — flushing, nausea, and headache. Controlled human studies have not reproduced a true disulfiram reaction, so the effect appears real but uncommon and usually mild. Most product labels still advise avoiding alcohol during treatment and for a short period afterward as a precaution.
azathioprine + allopurinol
Allopurinol blocks one of the two enzymes that normally clear azathioprine from the body, so the same azathioprine dose becomes far more potent. The result is a well-documented and potentially fatal interaction.
maoi + 5-htp
5-HTP is the direct precursor to serotonin and bypasses the rate-limiting step of serotonin synthesis. Combined with an MAOI, which blocks serotonin breakdown, serotonin can rise to dangerous levels and trigger serotonin syndrome, a potentially life-threatening reaction.
smoking + oral contraceptives
Combining cigarette smoking with combined (estrogen-containing) oral contraceptives raises the risk of heart attack, stroke, and blood clots more than either exposure alone, especially after age 35 and with heavier smoking.
spironolactone + potassium
Spironolactone makes your body hold on to potassium instead of flushing it out. Adding a potassium supplement, salt substitute, or potassium-loaded diet on top of that can push blood potassium to a dangerous level.
paroxetine + st. john's wort
Paroxetine is an SSRI that raises serotonin by blocking its reuptake. St. John's wort independently raises serotonin and also induces drug-metabolizing enzymes and P-glycoprotein. Taken together, the additive serotonin effect can precipitate serotonin syndrome, and paroxetine is among the most frequently implicated SSRIs in published St. John's wort case reports.
venlafaxine + st. john's wort
Venlafaxine is a serotonin-norepinephrine reuptake inhibitor (SNRI). St. John's wort independently inhibits serotonin (and to a lesser extent norepinephrine and dopamine) reuptake. Combining them can drive synaptic serotonin higher and trigger serotonin syndrome, and St. John's wort can also reduce venlafaxine exposure by inducing drug-metabolizing enzymes such as CYP3A4.
probiotics + immunosuppressants
In people whose immune systems are pharmacologically suppressed (for example by calcineurin inhibitors, mTOR inhibitors, corticosteroids, or mycophenolate), live probiotic organisms can occasionally cross the gut wall and enter the bloodstream, causing bacteremia, endocarditis, or sepsis. Case reports and a matched case-control study document Lactobacillus and Bifidobacterium bloodstream infections in transplant and oncology patients, with some strains naturally resistant to first-line antibiotics. The event is uncommon but serious.
escitalopram + st. john's wort
Escitalopram is a selective SSRI cleared mainly by CYP2C19 and CYP3A4. St. John's wort independently raises serotonin tone and is a strong inducer of those same enzymes and P-glycoprotein. Taken together, the combination can add to serotonergic effects and, through enzyme induction, lower escitalopram levels and blunt its antidepressant effect. Documented serotonin syndrome cases with St. John's wort involve other SSRIs rather than escitalopram specifically, so the combination is best avoided rather than treated as a guaranteed emergency.