herbal
7 interactions related to herbal
adderall + st. john's wort
Adderall (mixed amphetamine salts) raises synaptic norepinephrine, dopamine, and to a lesser extent serotonin. St. John's Wort inhibits reuptake of those same monoamines. Together they can push the serotonergic system far enough to risk serotonin syndrome and can add cardiovascular strain. Separately, St. John's Wort strongly induces the CYP3A4 enzyme and P-glycoprotein, which can blunt the effect of many co-taken medicines.
methylphenidate + st. john's wort
Methylphenidate treats ADHD by inhibiting reuptake of dopamine and norepinephrine. St. John's Wort adds its own monoamine reuptake activity and is a strong inducer of the CYP3A4 drug-metabolising enzyme. A small published observation suggests St. John's Wort can blunt methylphenidate's effect on ADHD symptoms. There is also a theoretical, additive serotonergic risk, mainly relevant if other serotonergic drugs are present, but no confirmed serotonin syndrome cases have been reported for this specific pair.
metoprolol + hawthorn
Hawthorn (Crataegus) has mild vasodilatory and heart-supporting effects that can add to the blood-pressure and heart-rate lowering of metoprolol, modestly increasing the chance of low blood pressure, a slow pulse, dizziness, or fainting. The interaction is pharmacodynamic (it happens at the receptor and tissue level), not metabolic, so taking the doses at different times does not prevent it.
lemon balm + valerian
Lemon balm (Melissa officinalis) and valerian (Valeriana officinalis) both act on the brain's GABA system but at different points — valerian's valerenic acid nudges the GABA-A receptor while lemon balm's rosmarinic acid slows the enzyme that breaks GABA down — and the combination has been used as a gentle aid for restlessness and sleep difficulty. The effect is mild rather than pharmaceutical.
maoi + st. john's wort
St. John's Wort raises brain serotonin, norepinephrine, and dopamine through reuptake inhibition and shows weak monoamine oxidase inhibition. Layered on a prescription MAOI, which blocks the breakdown of those same monoamines, the combination can push monoamine signaling to dangerous levels and is contraindicated because of the risk of serotonin syndrome and hypertensive crisis.
diphenhydramine + valerian
Diphenhydramine (a sedating antihistamine) and valerian root both depress the central nervous system, through histaminergic and GABAergic pathways respectively. Taken together their sedative effects add up, increasing drowsiness, next-day impairment, and fall risk.
passionflower + lemon balm
Passionflower (Passiflora incarnata) and lemon balm (Melissa officinalis) are both traditional calming herbs that act on the brain's GABA system - the main "slow down" signalling network. In laboratory studies, passionflower flavonoids appear to make GABA-A receptors more responsive, while lemon balm compounds appear to slow the breakdown of GABA. Because both lean in the same calming direction, taking them together is plausibly additive. There is, however, no human trial of this specific two-herb pair, so any combined benefit is theoretical and likely mild. The practical point is the shared sedative tendency: combining them with each other, or with other sedatives, can add up.