Finding Alternate Routes
Although oral delivery is generally the easiest option, the enteral route, which runs from mouth to anus, isn’t always an accessible or feasible pathway. Factors such as the hostile environment of the stomach, which can break down a medication too quickly, or issues with the gastrointestinal tract’s function—or lack thereof—can make this route a poor option.
“When I was an intern at Los Angeles County Hospital, I had a patient with fairly significant tuberculosis,” Beninger said. “The upper gastrointestinal tract was not working at all, so giving oral drugs—which make up about 90% of TB medications—wasn’t possible. So I asked a senior resident physician about administering the drugs per rectum.”
The resident’s response? “Great idea, figure it out.”
So, Beninger worked with the hospital’s pharmacist who created a formulation of the medication that could be delivered via suppository. “There are a small number of drugs routinely given that way, but for those that aren’t, they require a special preparation, which isn’t commercial,” he said.
“Pharmacists have the authority to prepare what they call compounded drugs,” Beninger said. “When they go to pharmacy school, they learn specific skills —which have taken hundreds of years to develop in the field—to be able to create and deliver drugs for specific scenarios, and in many cases that don’t have preservatives in them.”
In prescription medications, preservatives work much like they do in foods. They extend the shelf life of drugs by preventing oxidation of active ingredients, which can diminish potency. They also maintain colors, keep drugs shelf stable, and prevent the growth of bacterial or fungal contaminants in water-based solutions, such as nasal sprays.
But for some patients, these preservatives can cause irritation, inflammation, or allergic reactions, which is why for some treatments a clinician may seek to use a drug formulation that is preservative-free.