1. Hyperbaric oxygen therapy can interact with many prescription drugs through several pharmacological mechanisms, as it affects various body systems like circulation and respiration. 2. Specifically, HBOT can alter drug absorption, distribution, metabolism and excretion by changing cardiac output, blood glucose levels, and generating oxygen free radicals that impact biological membranes and enzyme activity. 3. The document provides examples of drug classes like anesthetics, narcotics, beta blockers, and stimulants that could have their effects decreased or increased when combined with HBOT, and recommends close monitoring of medications when administering HBOT.

1. HBOT and Possible Drug interactions
Fact:
1. 40% of olderAmericanstake 5 or more therapeuticagentspermonth
2. 50% of the populationtakesone ormore prescriptiondrugspermonth
Oxygenpossessesbothbiochemicalandphysiologicactionstothe body. Oxygenwhenusedin
concentrationsabove atmosphericquantitiesitisconsideredadrugandneedsprescribed.
Pharmacology Principles
1. Pharmacokineticsisthe science thatdescribesthe body’sactiononamedicinal agent.
2. Pharmacodynamicsisthe science thatdescribesthe agentsactiononthe body’ssystems.
Pharmacokineticsinvolvesfourmajorbodyfunctions;
1. Absorption
2. Distribution
3. Metabolism
4. Excretion
Once absorbedmostdrugs bind toplasmaproteinsthatare specificforsome aspectorstructural
feature of the drug taken.
Drug distributionisthe processbywhichadrug reversiblyleavesthe bloodstreamandenters
extracellularfluidorthe cellsof the tissues.Drugscan be distributedintodifferentcompartmentsof the
bodyby blood,plasma,fator bone.
Drug Metabolism
Drug metabolismisabiochemical enzyme mediatedreactionresultinginstructural modificationtothe
drug that changesitsbiological activityandorwater solubility.Drugmetabolismoccursas a resultof
enzymaticreactiononthe the medicationsresultinginmetabolitesthatmaybe active or rendered
inactive.Bodyorganssuchas the gastrointestinal wall,lungs,andliveraswell asthe bloodpossess
enzymesthatmetabolize drugs. Metabolismviathe endoplasmicreticulumof the liveristhe firststepin
the eliminationof manydrugs.Drugmetabolismbythe liveroccursthroughone or bothbiotransf
ormationreactionsclassifiedaseitherPhase 1or Phase 2 reactions. Phase 1 reactionsmodifythe drug
by usingoxidation,hydrolysis andreduction.Oxidationinvolvesthe enzymaticadditionof oxygenor
removal of hydrogen,carriedoutbymixedfunctionoxidases,ofteninthe liver.Oxidative reactions
typicallyinvolve acytochrome P450 monooxygenase,NADPH,andoxygen.These modifyingreactions
create a more polarand highlywatersoluabledrugmolecule foreliminationbythe kidney.Phase 2
reactionsmodifythe drugpharmacologicallytoaninactive formusingconjugationresultingin
glucoronides,acetates,andsulfates.Thisisaccomplishedbythe formationof acovalentlinkage
betweenafunctional groupappearingonthe parentdrugas a resultof Phase 1 Metabolismand
endogenouslyderivedglucoronicacid,sulfate glutathione,aminoacids,oracetate.Thisnew drug
metabolite maynowbe excretedbythe kidneys.
Hyperbaric Oxygenationand Pressure on Human Physiology
The hyperbaricenvironmentisassociatedwithphysiologicchangesinthe central nervoussystem,
endocrine system, respiration,andbodyhemodynamics.Bloodglucoselevelshave proventobe
affectedbyHBOT andresultindrops of bloodglucose levels.Diabeticptsmustbe monitoredcloselyand

2. usuallyinsulindosagesmayneedtobe change toaccount for these drops.Hyperoxiasuppressesthe
respiratoryreactivitytoCO2. Hyperbaricoxygenreversiblydepressesthe hypoxicventilatorydrive bya
directeffectonthe CarotidCO2 chemoreceptors.Hyperbaricoxygenalsoresultsinadecrease of cardiac
outputby 10-20% due to heartrate reductionratherthana reductioninstroke volume.Hyperbaricand
hyperoxicconditionscause changesincardiacoutputdistribution.Arterial liverperfusionwas
significantlyincreasedwhilekidneyandspleenperfusionwere significantlyreduced. Increasesinpartial
pressure of oxygeninthe blooddisturbsthe reductionof oxyhemoglobincausinganincrease in
solubility of CO2,thusthere isa retentionof CO2leadingtoa slightrise of H+ ionsin the tissues.
It is plausible to make the assertion that hyperbaric and hyperoxicenvironments may affectdrug
absorption due to reduced cardiac output!
Drugs that act on cellularmembranesinclude anesthetics,narcotics,and tranquilizers.These
medicinesare all affectedby an increase in atmosphericpressure changes that resultin observed
decreasedeffectiveness.
The generationof oxygenfree radicals relatedto high PO2 valuesaffect the permeabilityofbiological
membranes.Oxygenfree radicals are highlyreactive, toxicentitiesthat induce lipidperoxidationand
may alter both proteinsand nucleicacids!
Drugs displayinga highprotein bindingrate shouldbe affecteddemonstratingan alteredvolume of
distributionand altereddrug clearance because of the generationofoxygenfree radicals.
Combiningthe observedrespiratory depressingeffectsofhyperbaricoxygenand the drug induced
depressionobservedwithnarcotic analgesics,the clinicianmust considerthat a potential for an
elevationinphysiological paCO2 causing vasodilationand the potential for oxygentoxicity doesexist
whenusing narcotics and HBOT.
Central nervous systemstimulants such as methylphenidate mayinteract unfavorablywith HBOT and
may predispose the patient to oxygentoxicity.
Hypertensivessuchas beta blockers shouldbe avoidedduringHBOT as the results showed that in
patientsusing beta blockersas well as beingdiabeticcaused a significantelevationofblood pressure
while reducingheart rate!
Research has producedfindingssuggestingthat the effectivenessofcardiac glycosides(Digoxin) was
decreasedinHBOT. Initial animal results also showthat heparintreated animals exposedtoHBOT
developpulmonaryhemorrhage.
See associated chart with article and observationsand recommendationsof certain drugs and HBOT.