What happens when you take Adderall with St. John's Wort?
Adderall is a mixed-salt amphetamine product (dextroamphetamine and levoamphetamine) prescribed primarily for attention deficit hyperactivity disorder (ADHD) and narcolepsy. Amphetamines increase synaptic levels of dopamine and norepinephrine by triggering their release from presynaptic neurons, blocking their reuptake, and weakly inhibiting monoamine oxidase. Amphetamines also produce a modest serotonergic effect, especially at higher doses.
St. John's Wort (Hypericum perforatum) is a herbal antidepressant whose active constituents (hyperforin, hypericin) inhibit reuptake of serotonin, norepinephrine, dopamine, GABA, and glutamate. It also has weak monoamine oxidase inhibition in vitro. Crucially for drug interactions, St. John's Wort is a powerful inducer of cytochrome P450 3A4 (CYP3A4) and the P-glycoprotein transporter, which affects metabolism of many co-prescribed drugs.
Combining the two stacks monoaminergic effects on multiple neurotransmitter systems simultaneously. The two main clinical risks are serotonin syndrome (from additive serotonergic load) and hypertensive or sympathomimetic toxicity (from additive norepinephrine and dopamine effects). A secondary, less acute concern is that CYP3A4 induction by St. John's Wort may shift amphetamine metabolism in unpredictable ways - amphetamine is metabolized primarily by CYP2D6 but with smaller CYP3A4 contributions.
Why is this important?
Drugs.com Professional classifies this interaction as significant and warns that 'coadministration of an amphetamine and another serotonergic agent may result in serotonin syndrome, because both drugs affect the serotonergic neurotransmitter system.' Serotonin syndrome symptoms include confusion, agitation, hallucinations, seizures, extreme blood pressure changes, increased heart rate, fever, sweating, shivering, tremor, muscle rigidity, and incoordination. Severe cases can result in coma and death. There is no antidote; management is supportive (cooling, benzodiazepines, sometimes cyproheptadine) and stopping the offending agents.
The risk is highest when:
- Doses of either agent are escalated
- Adderall is misused or abused at supratherapeutic doses
- Other serotonergic drugs are present (SSRIs, SNRIs, tramadol, fentanyl, triptans, lithium, MDMA, dextromethorphan, linezolid)
- The patient has a genetic CYP2D6 'poor metabolizer' phenotype, leading to higher than expected amphetamine levels
People with ADHD often struggle with comorbid depression or anxiety, which makes the temptation to add an over-the-counter 'mood support' supplement understandable. St. John's Wort is sold in this category and seems benign compared to a prescription antidepressant. It is not. Studies suggest St. John's Wort may also diminish methylphenidate efficacy in ADHD, and similar concerns apply to amphetamines. Patients sometimes report that their Adderall 'stops working' after they start St. John's Wort, partly because of CYP induction and partly because of receptor-level effects.
Finally, both substances raise heart rate and blood pressure. The combination has been associated with palpitations, chest pain, elevated blood pressure, and in rare cases hypertensive crisis. Anyone with pre-existing cardiovascular disease, a family history of sudden cardiac death, or structural heart abnormalities is at particularly elevated risk.
What should you do?
If you take Adderall (or any amphetamine-class stimulant), do not start St. John's Wort. If you are already taking both, do not stop abruptly without medical guidance, but contact your prescriber promptly. They may recommend discontinuing St. John's Wort, adjusting the Adderall dose, or substituting a prescription antidepressant that has been studied in combination with stimulants (such as bupropion, which is itself a stimulant-friendly antidepressant for ADHD-plus-depression patients).
Watch for early signs of serotonin syndrome: restlessness or agitation, sweating, shivering, dilated pupils, tremor, twitching, muscle rigidity, fever, racing heart, elevated blood pressure, or confusion. If you develop these symptoms, stop both substances and seek emergency care. Bring all bottles, including supplements, so clinicians can identify everything you have been taking.
If you are switching from St. John's Wort to Adderall, plan a brief washout period and discuss timing with your prescriber. CYP3A4 induction from St. John's Wort takes about two weeks to fully reverse, so any other CYP3A4-metabolized medications you take may need dose review during that window.
Which specific products are affected?
Amphetamine-class stimulants:
- Adderall and Adderall XR (mixed amphetamine salts)
- Dexedrine and Dextrostat (dextroamphetamine)
- Vyvanse (lisdexamfetamine)
- Mydayis (mixed amphetamine salts, extended release)
- Evekeo (amphetamine sulfate)
Methylphenidate-class stimulants carry similar concerns:
- Ritalin, Concerta, Daytrana patch, Quillivant, Cotempla, Jornay PM
- Focalin and Focalin XR (dexmethylphenidate)
St. John's Wort products to watch for:
- Single-ingredient capsules and tablets (standardized to 0.3% hypericin or 3-5% hyperforin)
- Tinctures, teas, and liquid extracts
- 'Mood,' 'calm,' 'positive,' or 'happy' combination supplements
- Products labeled Hypericum perforatum
The bottom line
Adderall plus St. John's Wort is a meaningful interaction with two real risks: serotonin syndrome and elevated cardiovascular load. The combination is not as immediately catastrophic as MAOI plus St. John's Wort, but it is on the avoid list for good reasons. If you are taking a stimulant for ADHD or narcolepsy and you are tempted to add an herbal mood supplement, talk to your prescriber first. There are safer evidence-based options for depression plus ADHD, and skipping the herbal aisle is the easy win here.