Photo Courtesy of Kathea Pinto
Drug-Drug interactions remind me of Haiti. Specifically I think of the bokor (folk medicine healer vs. witch doctor) who used to sit under the flambeau trees at an outdoor market at Deschappelles, near the compound of Albert Schweitzer Hospital. He would set out a lazy susan swirl tray of capsules and tablets arranged by color. Patients would spin it like like a Vegas roulette wheel, picking a pink one and a turquoise one or some other mixture for malaria or hypertension. The hospital staff was persistent in telling patients that you couldn't take medicine that way. But the bokor always had supplies and customers, some of whom ended up admitted to the hospital.
I think about that roulette twirl these days as I’m learning more about Drug-Drug interactions in the US in a medical toxicology fellowship at the North Texas Poison Control Center in Dallas Parkland Hospital. Bad pharmaceutical consumption out of home medicine cabinets is a common history I hear. Every week or so I see patients who jiggered up their personal suicide attempts with a combination of benzodiazepines, street drugs, opioids and alcohol. Other patients are toddlers who went candy hunting in grandmother’s purse.
Another category of drug interactions –unintended and often undetected– occurs in US hospitals. Those Drug-Drug interactions are the focus of a study published in Pediatrics this month.
Dr. Feinstein et al. (doi: 10.1542/peds.20142015) investigated potential Drug-Drug interactions (PDDI) among almost half a million hospitalizations in 2011 in forty-three pediatric hospitals. They classified PDDI as contraindicated (shouldn’t be used together), major (life-threatening or medical intervention needed), moderate (may change the patient’s condition or require medical intervention) and minor (limited clinical effect). They used an administrative database to calculate the potential interactions in a retrospective cohort study.
The researchers from Colorado and Philadelphia founded that 49% of the admitted children (approximately 245,000) had one or more PDDI. A contradicted PDDI occurred in 1% of admissions. Opioids were were involved in 25% of of all PDDI, followed by anti-infective agents (17%), neurologic agents (15%), neurological agents (15%), gastrointestinal agents (13%) and cardiovascular agents (13%).
The likelihood of PDDI exposures increased with length of hospital stay. Among infants, 21.8% were exposed to a PDDI on the first day.
The authors have done a study showing potential PDDI, not actual data and have done it using an administrative database. But their work is important because it suggests how frequent Drug-Drug interactions might be. The numbers of reported adverse drug events are much lower. In 2003, 10% of pediatric hospitalizations were reported to have included an adverse drug effect.
In short, the work done by the Colorado and Philadelphia researchers suggests that actual prevalence of Drug-Drug interactions might be under reported. More work is needed to verify how often such Drug-Drug interactions happen. There’s a big gap between the potential 49% reported here and the actual reported 10%.