Home Analysis Making the move from IV to PO antibiotics

Making the move from IV to PO antibiotics

While evidence is scarce, a pediatric hospitalist shares his strategies for making the switch

April 2010

Published in the April 2010 issue of Today’s Hospitalist

A pediatric hospitalist in New Haven, Conn., has a hard time convincing other physicians at his hospital that patients with osteomyelitis can be switched from IV to oral antibiotics.

Read how the University
 of Michigan embarked 
on an antibiotic stewardship program. February 2017: Prescribing too many antibiotics?

Another pediatric hospitalist wonders whether moving to oral antibiotics is a good idea for children with head and neck infections.

And a Salt Lake City-based physician asks if her hospital’s aggressive practice of sending patients home with PICC lines to treat complicated pneumonia is the best option.

“If you have one go-to antibiotic from each class, it will simplify switching decisions.”

~ Samir S. Shah, MD, MSCE
Children’s Hospital of Philadelphia

These were just a few of the issues raised during a pediatric hospital medicine conference session held last summer in Tampa, Fla. Samir S. Shah, MD, MSCE, a hospitalist and infectious diseases physician with Children’s Hospital of Philadelphia and research director of the University of Pennsylvania’s department of global health, reviewed strategies for switching from IV to oral therapy for common childhood infections.

While there are many good reasons to make that switch, the decision to shift to oral antibiotics is “usually based on empirical observations rather than controlled studies of outcomes,” Dr. Shah admitted. That lack of evidence is “one of the big limitations in this issue,” he pointed out, and makes it even more important for hospitalists to become comfortable thinking about IV-to-PO conversions.

Why make the switch?
One of the forces driving the shift to oral therapy, said Dr. Shah, is the economic pressure to reduce costs and resource utilization.

But making the switch is also better for patient safety. Patients moved to oral therapies have less chance, he pointed out, of developing hospital-acquired infections, and they spend less time in the hospital. And hospitalists switching to PO antibiotics may see fewer adverse events.

“Errors in drug preparation,” he said, “are much more likely when you’re trying to use an IV antibiotic as opposed to an oral formulation.”

When determining when “or if “to switch to oral antibiotics, Dr. Shah encouraged pediatric hospitalists to use a mnemonic they can all remember: COLIC.

C: Clinical improvement is observed. “Ideally, you would like to see the patient getting better, and you’d like to know your antibiotic is working before you even think about making the switch,” he said.

O: Oral route is not compromised. Make sure that patients aren’t suffering from conditions that impair absorption and prevent them from maintaining ideal serum concentrations. Possible deal-breakers include vomiting, severe diarrhea, inflammatory bowel disease and colitis.

Another barrier to switching: patients who refuse to take oral medications. “It ends up being challenging in that two- to four-year-old age group, where they’re strong enough to actually fight you and stubborn enough to not know what’s good for them,” Dr. Shah said.

L: Laboratory or other markers is improving. Seeing such improvement isn’t necessary for pneumonia or UTI patients, said Dr. Shah. But there are conditions, including osteomyelitis, where you want to see an improvement in C-reactive protein (CRP) levels before switching patients to oral antibiotics. “We check CRP daily for the first couple of days,” said Dr. Shah. “You want to see what the peak is and be clear about the magnitude of CRP decrease that constitutes clinical improvement.”

I: Indication for oral therapy. “For most diseases,” Dr. Shah explained, “and certainly the ones that you commonly see “pneumonia, complicated pneumonia, UTI, and skin and soft tissue infections ” you can be fairly aggressive about switching from IV to oral therapy.” For some diseases, however, such as meningitis, endocarditis and necrotizing fasciitis, it’s not a good idea to make the switch.

C: Comparable oral antibiotic option. “This becomes a little bit difficult as you start using broader spectrum antibiotics,” noted Dr. Shah. The easiest scenario is switching to the same drug in oral form. Fortunately, he added, several antibiotics have “good oral bioavailability,” meaning that much of the drug taken in oral form is absorbed.

Those include levofloxacin, clindamycin, ciprofloxacin, metronidazole and TMP-SMX. “When you give IV vs. oral, you actually achieve comparable serum concentrations,” Dr. Shah pointed out. “The doses may be a little bit different, so just use the doses recommended in your formulary.”

Exceptions to that formulary rule, he said, occur in the “handful of situations” where you know in advance that penetration is going to be an issue, such as osteomyelitis. In those situations, “you might want to use the elevated doses that are commonly described in textbooks,” said Dr. Shah.

Other switching options
With other antibiotics, however, doctors may be switching to the same drug that, in its oral form, has limited bioavailability. In that case, Dr. Shah said, hospitalists need to prescribe higher doses. Examples include cefotaxime and azithromycin, he said, and an oral form of ampicillin that isn’t often used in the U.S.

Then there are situations where doctors will want to switch to an oral form of a different drug that has good bioavailability. The trick, Dr. Shah pointed out, is deciding whether you need to cover the same spectrum of bacteria as the IV medication you’re switching from. (See “Making the switch” below.)

That concern commonly comes up when patients are on a broad spectrum IV antibiotic like ceftriaxone. “What do you send this child home on?” Dr. Shah asked. Are you comfortable that a patient doesn’t have some highly-resistant bug? If the answer is yes, it’s OK to opt for more narrow therapy.

“I’m not sure how you actually determine that if you don’t have an organism isolated from a sterile site,” said Dr. Shah. That’s often the case when switching therapies for pneumonia, complicated pneumonia and, occasionally, cellulitis. With UTIs, on the other hand, “You virtually always know both the bacteria and the antibiotic susceptibility patterns.”

Then there are situations where physicians may choose to go with a different drug that has limited bioavailability. When making such a choice, it’s helpful to remember which drugs are in the same class as the therapy used in IV form.

“Most antibiotics within a particular category,” Dr. Shah noted, “have a similar spectrum of activity,” even though drugs in a class do exhibit clear differences.

Within the second-generation cephalosporins, for instance, cefprozil and cefuroxime have different rates of absorption and achieve different serum concentrations. While you may need to consult with infectious disease specialists on subtle differences within each class of drugs, “If you have one go-to antibiotic from each class,” Dr. Shah said, “it will simplify these switching decisions.”

Putting theory into action
Doctors at the conference also raised key concerns, including what to do when hospitals are in the habit of discharging patients home with PICC lines for complicated pneumonia and osteomyelitis and are reluctant to switch to orals.

According to Dr. Shah, there are situations when hospitalists should keep a PICC line post-discharge. Some children, for example, tend to be allergic to a host of different oral antibiotics. Or long-term PICC line use may be needed because of a child’s or family’s inability or unwillingness to comply with an oral regimen.

Otherwise, “if you meet the COLIC criteria, there’s no reason to use IV antibiotics,” Dr. Shah explained, “because the absorption rate for most of these antibiotics is good.”

At his hospital, for instance, patients with complicated pneumonia are first treated empirically with clindamycin and cefotaxime. A reasonable oral therapy would be clindamycin plus high-dose amoxicillin clavulanate ES, he said, “so you have less frequent dosing and probably fewer side effects.”

As for convincing other physicians in your hospital ” particularly ID doctors “to switch osteomyelitis patients to PO antibiotics, “people generally respond to data,” said Dr. Shah. Fortunately, a study that showed benefits to moving acute osteomyelitis patients to oral therapies was published in the Feb. 2, 2009, issue of Pediatrics. He suggested convening a meeting with hospitalists, infectious disease and ED doctors, and orthopedists to discuss how to manage these patients. “If you get one group on board,” Dr. Shah said, “it may help change the thinking of the others.”

Sending children home
To determine how well patients can tolerate PO antibiotics, Dr. Shah said he starts by not interrupting IV therapy, but just substituting an oral dose.

“That way, if the child spits it out, it doesn’t matter,” he explained. The point of giving patients an oral dose is to make sure they can keep it down. For PO clindamycin, he said, he and his colleagues have had success breaking open capsules and mixing the drug with chocolate or cherry-flavored syrup.

“You like them to take at least two doses by mouth before they go home,” he said. He also insists that the family fill any antibiotic prescription at the hospital before they leave. “The worst thing is if they go to a community pharmacy that can’t give them the preparation,” he pointed out. “That child may miss a dose or two.”

As for sending osteomyelitis or complicated pneumonia patients home on PO antibiotics, Dr. Shah said the hard part is “emphasizing to the family that this is a serious infection, and they need to take every dose of every antibiotic prescribed.” That’s one reason why, he said, he never refers to switching to oral therapy as “step-down” treatment: “You need to stress that this is a serious infection and a big deal.”

It is also important, Dr. Shah said, to tell parents to call immediately if the child develops diarrhea or vomiting, or misses more than one dose of the medication. “It’s not just saying, ‘Alright, here are your prescriptions. Go on home,’ ” Dr. Shah told audience members. “It’s ensuring that they understand the consequences of not being compliant with these medications.”

Finally, Dr. Shah urged hospitalists to touch base with a patient’s pediatrician, just to fill the outpatient physician in on the patient’s oral therapy.

Ingrid Palmer is a freelance health care writer based in West Chester, Ohio.

Making the switch? Expect these barriers

WHILE THERE ARE MANY GOOD REASONS to switch patients from IV to oral antibiotics as soon as possible, hospitalists often run into clinical or cultural barriers to making that transition.

At a session on IV to PO antibiotics held during a pediatric hospital medicine conference last summer, Samir S. Shah, MD, MSCE, a hospitalist with Children’s Hospital of Philadelphia, discussed many of those issues, including the following:

Unnecessary testing? One audience member mentioned that when it comes to patients with complicated pneumonia, her hospital tends to do a lot of indirect testing such as ASL and pneumococcal antibody titers and nasopharyngeal swabs to look for MRSA. The goal is to try to narrow antibiotics to monotherapy, but she wondered if all that testing is worthwhile.

“One of the problems is that indirect testing tells you nothing about your susceptibility patterns, and it doesn’t actually prove what’s the causative pathogen,” explained Dr. Shah. “Unless you’re doing testing on something from a sterile site, I’m not sure I would believe the results.”

Head and neck infections. When considering switching patients to oral antibiotics for head and neck infections like lymphadenitis, Dr. Shah said that doctors need to consider the cause of infection, which could be bartonella, atypical mycobacteria or actinomyces. “We still use clindamycin empirically for those infections,” he said, and then wait 48 hours to see if it’s working.

What to do next “probably depends on a lot of different factors, including the regional prevalence of not just MRSA, but staph aureus susceptibilities to other antibiotics,” Dr. Shah said. “This is a situation where we may slowly be moving toward combination empiric therapy for these infections.” That means, he added, that hospitalists will have to think about moving to combination oral therapy for these patients as well.

Antibiotic costs. An attendee pointed out that the infectious disease service at her hospital was increasingly using linezolid for complicated pneumonias. While oral linezolid tastes better than clindamycin, she pointed out, patients and families have a hard time affording linezolid after discharge.

Dr. Shah agreed that when you start with such broad therapy in IV form and don’t isolate a bug, you don’t have many options other than continuing patients on oral linezolid. The drug’s manufacturer does, he said, have a program called “RSVP” that helps provide that company’s drugs, including linezolid, to patients for several days “while you grapple with the insurance company to get this approved.”

Skin and soft tissue infections. Another hospitalist said that she’s repeatedly seeing treatment failure with oral TMP-SMX (Bactrim) with skin and soft tissue infections.

One problem with Bactrim, Dr. Shah responded, was that “it does not cover Group A strep very well, and Group A strep is still an important player in cellulitis.” A study in the June 6, 2009, issue of Pediatrics looked at treatment failure for different oral outpatient monotherapies for non-drained, non-cultured skin and soft tissue infections. The study found that when the odds of treatment failure were adjusted for several variables, including fever and abscess, “the failure rate was much higher for Bactrim than for beta-lactams,” Dr. Shah explained.

Now, if patients have only a few risk factors, “your probability of treatment failure with a beta-lactam alone is certainly lower than with just Bactrim,” he said. As the number of those risk factors rises, however, he urged hospitalists to consider combination oral therapy.