Download Nebulized Drug Compatibility Table Legend

tips on practice
By Michael Hahn, RPFT, RRT-NPS
Consider Nebulized Drug Compatibility
A significant number of
common drugs are nebulized in the field of respiratory care. Like old diehard RTs, some of these
drugs have been around
for many years, if not decades. Although many
doctors routinely prescribe multiple nebulized drugs, there has been relatively little
research done to determine their physicochemical compatibility and aerodynamic
behavior when nebulized together.
Conversely, parenteral (intravenous) and
enteral (gut) drug admixture research has
been quite extensive. This discrepancy is
somewhat surprising because millions of
nebulized drug admixture treatments are
given throughout the world each year. Furthermore, some surveys have determined
many patients disregard medical advice to
not admix incompatible or potentially incompatible nebulized drugs.
Lacking research and recommendations
in this area, there is no clear consensus
even among clinicians about which drugs
are compatible or incompatible. For that
reason, compatible drugs that can be co-
nebulized are sometimes given separately
(or in a different nebulizer) whereas drugs
that are clearly incompatible may be nebulized together (or nebulized separately but
in the same nebulizer).
Incompatible drugs should not be nebulized in the same nebulizer because there is
always some residual drug left following a
treatment. That is why nebulizers should be
labeled accordingly.
Theoretically, any injectable drug can be
administered via inhalation if it is diluted
accordingly. In respiratory therapy, inhaled
drugs are usually diluted with 0.9 percent
saline to optimize their pH, reduce their
concentration and make them iso-osmolar.
Otherwise, the undiluted drug might irritate
the airway and cause cough or bronchoconstriction.
Aerodynamic Behavior Modification
Drug Incompatibility Lingo
As you know, drug incompatibilities
may result from inadequate solubility or
acid-base (chemical) reactions, oxidation
reactions, photolysis, hydrolysis and warm
temperatures. Visual evidence of drug instability or incompatibility that you might
readily see is foaming, cloudiness, crystallization, precipitation or discoloration.
Chemical incompatibility might cause irreversible degradation of drugs and render
them therapeutically inactive or otherwise
toxic. Drug admixture incompatibility may
not be visually evident, however. Just because drugs appear to mix together and produce an aerosol does not necessarily mean
they are compatible.
Besides needing more definitive information about which nebulized drugs are compatible, caregivers also need to determine
the aerodynamic behavior when nebulized
drugs are admixed. Long ago it was established that the optimal mass median aerodynamic diameter (MMAD) of an inhaled
drug particle size is 3 to 5 microns.
Inhaled particles larger than 5 microns
may become deposited too high in the airways, and particles smaller than 3 microns
may be exhaled or deposited too deeply.
This is why drug manufacturers tend to focus on developing inhaled drugs that have
aerodynamic characteristics that will help
facilitate optimal drug deposit and therastory continued on page 24
Table Legend
Y = Compatible (if preservative-free solutions like benzalkonium chloride are not used).
? = Insufficient studies or no information.
NR = Not recommended.
T = Theoretically possible because it is in the same drug family as a drug that was previously studied.
Nebulized Drug Compatibility
Drug
albuterol
Albuterol
Budesonide
Colistin
Cromolyn
Dornase
Ipratropium
Levalbuterol
Mucomyst
R. Epi
Y
Y
Y
NR
Y
T
Y
T
Y
?
Y
NR
Y
Y
Y
T
NR
?
NR
?
T
?
T
?
NR
Y
Y
?
Y
NR
NR
NR
NR
NR
NR
Y
?
T
Y
Y
T
T
T
?
Budesonide
Y
Colistin
Y
?
Cromolyn
Y
Y
?
Dornase
NR
NR
NR
NR
Ipratropium
Y
Y
?
Y
NR
Levalbuterol
T
Y
T
Y
NR
Y
Mucomyst
Y
Y
?
?
NR
?
Y
R. Epi
T
T
T
Y
NR
T
T
T
Y
NR
?
NR
NR
Y
T
T
Tobramycin
Tobramycin
T
T
Other common nebulized drugs that could also be included are atropine, lidocaine, morphine, pentamadine; also saline & sterile water.
­­www.advanceweb.com/rcp August 20, 2007 ❘ ADVANCE for Respiratory Care Practitioners­