nyquil contains Doxylamine which is a first generation h1 blocker that causes delirium and sedation (the hat man) via its anticholinergic properties, very similarly to diphenhydramine (which is the main ingredient in American Benadryl). both of them, and hydroxyzine which is the prescription member of this drug class, cause cognitive decline and dementia when used regularly.
there is no ingredient in any of these medications that is "a precursor to meth",
you're thinking of ephedrine/pseudoephedrine, 2 drugs which were largely banned (theyre technically legal just much harder to get) several years ago and replaced with phenylephrine, which does not work:
Two studies published in 2009 examined the effects of phenylephrine on symptoms of allergic rhinitis by exposing people to pollen in a controlled, indoor environment. Neither study was able to distinguish between the effects of phenylephrine and a placebo.
the FDA hired an advisory council in 2023 and came to an official conclusion and published a statement that phenylephrine does not work, does nothing, is at best a placebo etc etc but because this is america you can keep putting it in your drug store medications and claiming it works.
In September 2023, an independent advisory committee to the U.S. Food and Drug Administration (FDA) unanimously agreed that there is insufficient evidence showing that "orally administered phenylephrine is effective as a nasal decongestant".[33] The committee also unanimously believes that this does not need further study. The FDA responded to the committee, stating it would take its advice under advisement.[23][34] In November 2024, the FDA proposed to remove oral phenylephrine as an active ingredient that can be used in over-the-counter (OTC) monograph drug products for the temporary relief of nasal congestion.[24]
thanks to the ongoing drug war, the entire american drug class of "cold medicine" is essentially now just over-the-counter delirients that "work" by knocking your ass out so you can just get some much needed sleep. and sleeping is a good way to recover from infection so whatever, but the dementia effects are real and not good. aside from that and the antihistamine activity, which IS effective dont get me wrong, they do nothing to address the actual symptoms of the virus. you get better cough suppression from straight alcohol probably
it's been weird watching the popular understanding of what drugs do which things drift farther and farther away from reality as successive generations of people use fewer and fewer drugs. methamphetamine is very famously a stimulant, it has no similarity in subjective effects to anything you could observe from Benadryl or NyQuil, and even when American cold medicine contained ephedrines, barely so.
