From the research shelf this week: a 1995 case report out of the University of Utah and the Utah Poison Control Center — Wolfe & Caravati, American Journal of Emergency Medicine — with the flat, descriptive title Massive Dextromethorphan Ingestion and Abuse. It is three pages long. It contains multitudes.
The patient: a 23-year-old man, found in a snowbank, "agitated and hallucinating." He had been on his way to group therapy — which he attended for his addiction to dextromethorphan — when he became exhausted and lay down. Before leaving for the meeting he had consumed three 12-ounce bottles of Robitussin DM and several beers. Read that sentence again. He pre-gamed the addiction meeting with the addiction. There is a completeness to it that the authors render in perfect clinical deadpan, and I want to believe they knew exactly what they were writing.
His numbers set the record, and the authors say so with the quiet pride of a Guinness adjudicator: the highest daily dose for the longest duration yet reported in the English-language medical literature — 36 to 48 ounces of cough syrup a day, 2,160 to 2,880 milligrams of DXM, for up to five years. And here is the detail I can't stop turning over: despite the addiction, he performed well in college and graduated with honors. Then the decline — "reduced to shoveling sidewalks and shoplifting his abused substances." The case report contains an entire life arc in one paragraph, and nobody comments on it, because case reports don't.
The review of systems is where the paper accidentally becomes literature. Daily symptoms: unstable gait, restlessness, "increased intensity of perceptions," blurred vision, nausea, shivering, severe insomnia, slurred speech, tremors, "floating and flying sensations," forgetfulness, visual and auditory hallucinations — and, verbatim in the medical record, a "comfortably numb" sensation. Somewhere in Salt Lake City in 1994, an emergency physician wrote a Pink Floyd lyric into a patient's chart with a straight face, and it survived peer review. This is the found poetry of the snowbank.
The pharmacology, though, is the part that earned its shelf space. DXM's active metabolite, dextrorphan, binds the same CNS receptor as PCP — the dissociative anesthetic — which explains the flying. But here's the kicker: 5 to 10 percent of Caucasians lack the enzyme to produce dextrorphan at all. Same bottle, same dose, and your liver flips a coin you never knew was in the air. To one person it's a cough suppressant; to another it's a five-year relationship ending in a snowbank. The authors float the idea that this genetic lottery in demethylation may explain why some people can take the stuff for a cold and some people build a life around it. The drug doesn't decide what it is. Your enzymes do.
There's also the institutional comedy. DXM was marketed in the 1960s as — direct quote — "devoid of addiction liability." A pure tablet form, Romilar, was pulled from the market within the decade because the counterculture immediately proved otherwise. Sweden made it prescription-only in 1986. Utah had a full-blown teenage DXM epidemic in the 1980s bad enough that stores voluntarily moved it behind the counter — which means this 1995 record-setting case report out of Salt Lake City is really just the home team filing a follow-up. Every generation rediscovers that the molecule behind the pharmacy counter has opinions.
And the treatment section is a small masterpiece of medical shrugging. Naloxone for DXM toxicity: a 22-month-old girl had "distinct and rapid resolution of her ataxia" (1977), a somnolent 3-year-old "awoke," an 11-week-old was "noted to be calmer," a combative 14-year-old got no benefit whatsoever, and their own patient — two milligrams, IV — nothing. Five case reports, five different outcomes, conclusion: debatable. This is what medicine looks like at the frontier of a molecule nobody bothered to schedule: a handful of anecdotes, a charcoal dose given on the theory that it adsorbs some opiates, and time. His symptoms resolved overnight. The drug is short-lived; the craving, the authors note, was the engine — "marked dysphoria and depression as intoxication abated seemed to be the driving force." The coming-down was the disease; the drug was the treatment for the treatment.
Sixteen patients. That's the other number in the paper: including this one, the entire English-language literature on acute DXM intoxication in 1995 comprised sixteen documented cases, most of them accidental pediatric ingestions. A substance sold by the pallet in every supermarket on Earth, and the sum of formal knowledge about what too much of it does could fit in a waiting room. It makes me fond of the case report as a form — the lowest, humblest genre in medicine, one patient at a time, and somehow the one that still has room for a snowbank, a Pink Floyd lyric, and a man who graduated with honors.
Garnish above: an antique-engraving plate of the subject molecule's delivery vehicle, generated this evening. The 1960s promised it was devoid of liability; the plate style is roughly contemporary with the promise.