A Standby Prescription for a Month of Solo Cycling Through Southeast Asia
A newly retired cyclist wants a standby antibiotic prescription before a month alone on rural roads in Vietnam and Cambodia. The disagreement isn't about whether traveler's diarrhea is a real risk for him — it's about whether handing him an antibiotic at all is the right answer, given how the resistance and colonization data have shifted.
P.H., a 58-year-old man, retired from teaching high school biology this spring after thirty-one years, and is using the first real block of unscheduled time in his adult life to do something he's wanted since he was twenty-two: cycle solo across Vietnam and into Cambodia, a month on rural roads with a tent, a bike he rebuilt himself over the winter, and long stretches between towns big enough to have a real pharmacy. His only chronic condition is type 2 diabetes, controlled on metformin alone at an A1c of 6.4%; because metformin does not drive glucose down the way a sulfonylurea or insulin would, a day of not eating on the road carries far less hypoglycemia risk for him than the same day would for most diabetic travelers, which quietly removes the reason his diagnosis would otherwise dominate this visit. He has never needed antibiotics for anything more than a sinus infection in his life, and the travel clinic visit is mostly about one specific question: does he need a "just in case" antibiotic for traveler's diarrhea, and if so, which one.
The honest answer has gotten more complicated in the years since fluoroquinolones were the reflexive standby prescription. Campylobacter, one of the more common bacterial causes of traveler's diarrhea across South and Southeast Asia, now carries fluoroquinolone resistance at a level high enough that the ISTM travelers' diarrhea guidance published by Riddle and colleagues moved away from that class entirely for this itinerary, toward azithromycin instead. But the bigger question sitting underneath the drug choice isn't which antibiotic he should carry — it's whether a month of mostly self-limited illness in an otherwise healthy, motivated traveler is the kind of exposure that should come with an antibiotic in his kit at all, given the COMBAT cohort's finding that travelers who take one for ordinary TD return home colonized with ESBL-producing Enterobacteriaceae at markedly higher rates than travelers who don't. The travel clinic's own intake note flags what the visit keeps circling back to and cannot resolve: he has no prior episode of traveler's diarrhea anywhere in his chart, so there is nothing in his own history to say whether he is someone whose gut shrugs this off in two days or someone who spends a week off the bike, and that is the one fact that would decide it.
What goes in the pannier, and what doesn't
I'd send him with a standby antibiotic. This isn't a week in a resort town with a pharmacy on every corner — it's a month alone on rural roads where the nearest reliable care could be a full day's ride away. Azithromycin, not a fluoroquinolone; Campylobacter resistance to fluoroquinolones across South and Southeast Asia is common enough now that Riddle and colleagues' ISTM guidance already moved past that class for exactly this itinerary.
He's not a high-risk traveler medically — his diabetes is well controlled and that's not really what's driving this. It's the itinerary itself: distance from care, physical demands of cycling while dehydrated, and a month-long window where any single bad week matters more than it would on a two-week beach trip.
I want to name a cost that gets skipped when this conversation stays focused only on his own trip: travelers who take an antibiotic for ordinary traveler's diarrhea come home colonized with resistant gut organisms — ESBL-producing Enterobacteriaceae, specifically — at meaningfully higher rates than travelers who manage the same illness with hydration and loperamide alone. That's not a hypothetical stewardship talking point — the COMBAT cohort followed travelers prospectively and found exactly that, with antibiotic use during travel an independent risk factor for coming home carrying resistant organisms.
I'm not disputing that access to care is genuinely limited on his route. I'm disputing that access limitation, on its own, justifies handing an antibiotic to every healthy traveler on every remote itinerary, when most TD in a patient with no prior history resolves in three or four days without one.
You are both arguing about whether he should be handed a bottle, and that is the wrong object. The prescription is not the intervention; the threshold he applies to it is, and neither of you has said a word about the threshold. Send him with the azithromycin, but give him a clear threshold: illness that stops him from riding, or that comes with fever or blood, not ordinary loose stools he can manage with loperamide and oral rehydration salts.
A standby prescription with real criteria attached isn't the same decision as an automatic one. If he's disciplined enough to rebuild his own bike over a winter, he can follow a three-line rule about when to open the pill bottle.
Agreed: azithromycin dispensed as a standby prescription, paired with an explicit written threshold — illness severe enough to stop him from riding, or accompanied by fever or blood, not ordinary loose stools manageable with loperamide and oral rehydration salts, which he leaves with regardless.
Not fully agreed: the stewardship physician still would have preferred no standing antibiotic prescription at all for a traveler this healthy, and said so directly at the end of the visit — his concession was to the compromise, specifically the written-threshold framing, not a change of mind about the underlying colonization risk. The travel medicine physician's own view, equally undisputed by the end, was that the access gap on this specific itinerary made the standby prescription the right call on its own, threshold or not. Both left comfortable with what P.H. is actually carrying; neither left agreeing on the general question the specific decision was built to sidestep.