The antibiotic intravenous infusion therapy is a common therapy in hospitals and it has become more popular in recent years, parallel to the increase in bacterial resistance to many common antibiotics that are administered orally. In these cases, antibiotic intravenous infusion therapy is the last line of defence against this type of bacteria, which already posed one of the greatest challenges to people’s health in the 21st century.

Choosing the right antibiotic to use depends on many factors related to the patient’s own state of health, their compatibility with other concomitant treatments and the pathogen’s sensitivity to that specific antibiotic.

Taking a culture (be it blood, urine, sweat or any other type of fluid or sample where the pathogen is present) is the best way to clearly identify which germ we are treating and which antibiotic is more sensitive, because normally an antibiogram is made along with the culture.

However, the patient’s state of health doesn’t often allow us to wait for the results of this culture, so the implementation of an empirical treatment is decided upon with a wide spectrum antibiotic, a treatment that can be confirmed or corrected depending on the pathogen that is identified in the culture and the resulting sensitivity from the antibiogram.

It is important to identify the patient’s possible allergies or intolerances before beginning an intravenous infusion of antibiotics, because there could be anaphylactic reactions.  

Intermittent infusion or continuous infusion?

There is wide scientific discussion concerning the advantages and disadvantages of the continuous infusion of antibiotics against the most common infusion, which is the  administration of a drug through boluses (generally several times per day, although it does depend on the type of antibiotic). A Cochrane review of different clinical trials published in 2013 didn’t uncover significant differences between the results of each type of antibiotic intravenous infusion therapy. However, trials are continuously being carried out in this respect, looking to increase the level of efficiency of available antibiotics against infections, without compromising their safety profile.

Factors to consider in antibiotic intravenous infusion therapy

The pharmacokinetics of the chosen antibiotic agent conditions dose and infusion time. In any case, the aim is to reach the Minimal Inhibitory Concentration (MIC) which allows it to act as effectively as possible.

In this sense, the antibiotics can be placed into two categories:

  • Time-dependent (those where the aim of the antibiotic is to be as much time as possible above the MIC). Beta-lactams and glucopeptides, for example, are placed in this group. For them to be efficient, its serum concentration must be above the MIC, 40-50% of the interval between doses, for intermittent infusions. For continuous infusion, a loading dose is established before starting the infusion in order to immediately reach the therapeutic dose.
  • Concentration-dependent. In these cases, priority is given to the maximum concentration (Cmax) being well above the MIC (generally 10 times), without being so dependent on time.  Aminoglycosides and fluoroquinolones, for example, are placed in this group.

The pharmacokinetics is also influenced by the patient’s health (for example, their ability to eliminate the drug through the kidneys), so the decision on the dose to be used must take these factors into account.

Furthermore, there are other considerations related to each type of antibiotic:

  • Stability time: Once dissolved, each type of antibiotic has a certain stability type, which conditions the infusion time.
  • Sensitivity to light.
  • Combinations of antibiotics: For serious infections or those caused by highly resistant germs, several antibiotics can be used in conjunction.  It is important to know if they can be administered at the same time or separately, as well as the interactions amongst themselves.
  • Dilution: Not all the antibiotics can use the same diluter, so attention must be paid to this point.
  • Effects in the area of catheter insertion: Some antibiotics, like ciprofloxacin, can cause phlebitis in the area where the catheter is inserted, so the latter must be closely monitored and changing it must be assessed if these symptoms occur.

The Chroma infusion pumps by arcomed can incorporate personalised libraries of drugs according to the needs of each hospital, which hugely facilitates the handling and intravenous infusion of antibiotics, both for medical professionals and nurses.