Drug interactions
These are the specific drug combinations patients and clinicians search for most. Each page covers the mechanism, the actual risk, and what to do about it. All the general CYP450 pharmacology sits in the clinician CYP450 guide; these pages are the interaction-specific deep dives.
Alcohol plus psychiatric medications
Alcohol interacts with most psychiatric medications: additive sedation with benzodiazepines and sleep aids, hepatotoxicity with acetaminophen and some drugs, dangerous with disulfiram and metronidazole, worsening depression regardless. What is actually safe.
Clozapine plus smoking (and quitting smoking)
Smoking induces CYP1A2 and speeds clozapine metabolism, meaning smokers need higher doses. When a clozapine patient quits smoking, levels can rise 50 to 100 percent over weeks, sometimes causing toxicity. What to do.
Grapefruit plus psychiatric medications
Grapefruit inhibits intestinal CYP3A4 for 24 to 72 hours per exposure. Which psychiatric medications are affected (buspirone, quetiapine, lurasidone, ziprasidone, carbamazepine, some benzodiazepines) and by how much.
Lithium plus NSAIDs: toxicity from reduced renal clearance
NSAIDs reduce lithium clearance by inhibiting renal prostaglandin synthesis, raising lithium levels 20 to 60 percent. Regular NSAID use in lithium patients can precipitate toxicity. What to do.
MAOI plus tyramine: the hypertensive crisis (cheese effect)
MAOIs plus tyramine-rich foods (aged cheese, cured meats, tap beer, fermented foods) can trigger acute hypertensive crisis. The full foods list, drug interactions, patch vs pill difference, and what to do.
SSRI plus tramadol: serotonin syndrome and seizure risk
Combining SSRIs or SNRIs with tramadol carries real risk of serotonin syndrome and seizures. Which combinations, what the actual incidence is, when it's still acceptable, and what to use instead.
SSRIs plus NSAIDs: bleeding risk (GI, brain, surgical)
SSRIs and SNRIs impair platelet function, and combining them with NSAIDs meaningfully increases GI bleeding, intracranial hemorrhage, and perioperative bleeding risk. Which patients are highest-risk and what to do.