herbal
7 interactions related to herbal
adderall + st. john's wort
Adderall (amphetamine/dextroamphetamine) raises synaptic norepinephrine, dopamine, and serotonin. St. John's Wort inhibits serotonin, dopamine, and norepinephrine reuptake. Combined, the serotonergic load can produce serotonin syndrome and a hypertensive response, while St. John's Wort's CYP3A4 induction may also alter amphetamine metabolism.
methylphenidate + st. john's wort
Methylphenidate inhibits dopamine and norepinephrine reuptake and modestly affects serotonin signaling. St. John's Wort adds reuptake inhibition of serotonin, dopamine, and norepinephrine, plus weak MAO inhibition. Combination risks serotonin syndrome and a published case series suggests reduced methylphenidate efficacy for ADHD.
metoprolol + hawthorn
Hawthorn (Crataegus) has mild vasodilatory and positive inotropic effects that can additively lower blood pressure and slow heart rate when combined with metoprolol, increasing the risk of hypotension, bradycardia, dizziness, or syncope. The interaction is pharmacodynamic, not metabolic, so spacing the doses does not prevent it.
lemon balm + valerian
Lemon balm (Melissa officinalis) and valerian (Valeriana officinalis) both modulate the GABAergic system but through different mechanisms — valerian's valerenic acid acts directly on GABA-A receptors while lemon balm's rosmarinic acid inhibits GABA transaminase to preserve GABA in the synapse — and the combination has been studied for restlessness, dyssomnia, and sleep quality.
maoi + st. john's wort
St. John's Wort inhibits serotonin, dopamine, and norepinephrine reuptake and has weak MAOI activity in vitro. Combined with a prescription MAOI, monoamine clearance is blocked at multiple levels, producing serotonin syndrome and/or hypertensive crisis.
diphenhydramine + valerian
Diphenhydramine (a sedating antihistamine) and valerian root both produce CNS depression through GABAergic and histaminergic pathways. Used together, sedation, psychomotor impairment, and respiratory depression risks are additive.
passionflower + lemon balm
Passionflower (Passiflora incarnata) contains flavonoids that act as positive modulators at the GABA-A receptor benzodiazepine site, while lemon balm (Melissa officinalis) inhibits GABA transaminase, the enzyme that breaks down GABA. The two herbs raise GABAergic tone through complementary mechanisms - one boosts receptor activity, the other extends GABA's half-life - which is the basis for several traditional anxiolytic and sleep formulas.