Chapter 15 Marini Pharmacotherapy

329

CHAPTER 15 • Pharmacotherapy

(short acting, but more expensive) or lorazepam (longer acting, but similar cost). For each patient, the clinician must decide if the safety advantages between the two equally effective options justify the cost. When two courses of therapy are equally safe and effective, cost should definitely be considered. For example, a urinary tract infection with Escherichia coli could be treated with generic enteral amoxicil- lin for pennies or with much more expensive (and broader coverage) intravenous extended spectrum penicillin for hundreds of dollars. Generic equiva- lents are almost always less expensive. Sometimes the choice is between two expensive drug therapies, as is the case with inhaled nitric oxide and nebu- lized prostacyclin for treatment of ARDS. Neither compound has proven outcome benefits, but both lower pulmonary artery pressures and may, at least temporarily, improve oxygenation in life-threatening hypoxemia. A protocol detailing who might qualify to receive these treatments and who has authority to prescribe them can save a large hospital hundreds of thousands of dollars annually with little compro- mise in treatment quality. Establishing an automatic substitution program in which the least expensive therapeutically equiva- lent compound is substituted for a brand named medication also saves money. Hospitals may bundle medications together with a manufacturer to secure lower costs for all medications in that bundle. For example, the hospital may decided to buy a proton pump inhibitor, a cephalosporin antibiotic, and an antifungal together to get a better pricing on all three than they could get individually. This may mean that a hospital will specify a preferred proton pump inhibitor or histamine blocker on formulary for use in preventing stress ulcers. Often, patients are changed to the preferred agent on admission to lower costs to deliver hospital care. Other saving opportunities include allowing for automatic substitution of oral agents for intravenous agents when the gut works and bioavailability is favorable. For example, oral flu- oroquinolones offer almost 100% bioavailability with significant cost savings over the parenteral route. The process of therapeutic substitution requires a proac- tive pharmacy committee and consensus, though not necessarily universal agreement, among local experts that the substitutions are reasonably equivalent. Reducing the number of like medications stocked by the pharmacy can also produce benefits. Pharmacy size is reduced, fewer personnel are necessary to

track and manage inventory, and waste is reduced as fewer expired drugs are discarded. In the case of restriction or substitution, however, a multidisci- plinary pharmacy committee must remain open to well-reasoned arguments for formulary additions or exceptions, and a process for formulary waiver must exist for emergency situations. Modifying Frequency and Route of Administration Surprisingly, the cost of a course of therapy often depends more on the route and frequency of admin- istration than it does on the drug acquisition cost. A patient is typically charged on average $20 to $40 for preparation of any intravenous medication. If the acquisition cost of that drug is $1, but is given four times a day, the preparation cost will far exceed the acquisition cost. In that situation, it may make more fiscal sense to choose an equivalent drug with higher acquisition cost that only needs to be given once daily. One example of this strategy is choos- ing ertapenem (given once daily) over piperacillin– tazobactam (given four times daily) for treatment of intra-abdominal infections. Even though ertapenem is more expensive to acquire, its overall daily cost is less. Other examples include substitution of once- daily tiotropium for ipratropium, which must be administered four times daily, or use of once daily low molecular weight heparin (LMWH) instead of unfractionated heparin (UFH) every 8 hours for venous thrombosis prophylaxis. Reducing the number of scheduled administrations each day has also been shown to be associated with fewer missed doses and thereby fewer treatment failures. As already mentioned, the route of therapy can impact costs. In general, the cost of an equivalent dose of an oral medication is one tenth to one hun- dredth that of the same drug given intravenously. This vast discrepancy exists because intravenous preparations are usually more expensive to purchase, some drug is frequently wasted (in single-use only vials), and there are substantial labor costs associ- ated with stocking, retrieving, mixing, transport- ing, and administering an intravenous preparation. Essentially, all patients eating or tolerating enteral nutrition can receive oral/enteral medications. In fact, many medications, including benzodiazepines, histamine blockers, proton pump inhibitors, narcot- ics, and some antibiotics, have equal bioavailability when given orally and intravenously. Hence, almost any time an intravenous preparation is changed to an oral route, substantial savings can be achieved.