Propofol cdhcvhgdgcfhfd bcsdvcsdgvgsfj bdvcvdcvdsjhgcvjsd bhcsdhbvj

8/9/2019 Propofol cdhcvhgdgcfhfd bcsdvcsdgvgsfj bdvcvdcvdsjhgcvjsd bhcsdhbvj

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PROPOFOL

TRI WIDHIYONO PAMUNGKAS

Pharmacokinetics

ASORPTION

Propofol is available only for intravenous administration for the

induction of general anesthesia and for moderate to deep sedation (see Table

87).

DISTRIUTION

The high lipid solubility of propofol results in an onset of action that is

almost as rapid as that of thiopental (one-arm-to-brain circulation time).

Awakening from a single bolus dose is also rapid due to a very short

initial distribution half-life (28 min).

Most investigators believe that recovery from propofol is more rapid and is

accompanied by less hangover than recovery from methoheital! thiopental!

or etomidate.

This ma"es it a good agent for outpatient anesthesia.

# lo$er induction dose is recommended in elderly patients because of their

smaller Vd.

%omen may re&uire a higher dose of propofol than men and appear to

a$a"en faster.

IOTRANSFORMATION

The clearance of propofol eceeds hepatic blood 'o$! implying the

eistence of etrahepatic metabolism.

This eceptionally high clearance rate ( times that of thiopental) probably

contributes to relatively rapid recovery after a continuous infusion.

*on+ugation in the liver results in inactive metabolites that are eliminated by

renal clearance. The pharmaco"inetics of propofol do not appear to be

a,ected by moderate cirrhosis.

se of propofol infusion for long-term sedation of children $ho are critically ill

or young adult neurosurgical patients has been associated $ith cases of

. lipemia!

. metabolic acidosis!


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/. and death.

!"#R!TION

#lthough metabolites of propofol are primarily ecreted in the urine!

chronic renal failure does not a,ect clearance of the parent drug.

!$ects on Or%an S&stems

#ARDIO'AS#ULAR

The ma+or cardiovascular e,ect of propofol is a decrease in arterial

blood pressure due to

. a drop in systemic vascular resistance (inhibition of sympathetic

vasoconstrictor activity)!

. cardiac contractility!

/. and preload

0ypotension is more pronounced than $ith thiopental but is usually reversed

by the stimulation accompanying laryngoscopy and intubation.

1actors eacerbating the hypotension include

. large doses!

. rapid in+ection!

/. and old age.

Pro(o)o* marke+*& im(airs the norma* arteria* ,arore-e. res(onse

to h&(otension/ (artic0*ar*& in con+itions o) normocar,ia orh&(ocar,ia1

2arely! a mar"ed drop in preload may lead to a vagally mediated re'e

bradycardia.

#han%es in heart rate an+ car+iac o0t(0t are 0s0a**& transient an+

insi%ni2cant in hea*th& (atients ,0t ma& ,e se3ere eno0%h to *ea+

to as&sto*e/ (artic0*ar*& in (atients at the e.tremes o) a%e/ on

ne%ati3e chronotro(ic me+ications/ or 0n+er%oin% s0r%ica*

(roce+0res associate+ 4ith the oc0*ocar+iac re-e. 5see #ha(ter 6781

Patients 4ith im(aire+ 3entric0*ar )0nction ma& e.(erience a

si%ni2cant +ro( in car+iac o0t(0t as a res0*t o) +ecreases in

3entric0*ar 2**in% (ress0res an+ contracti*it&1

A*tho0%h m&ocar+ia* o.&%en cons0m(tion an+ coronar& ,*oo+ -o4

+ecrease to a simi*ar e.tent/ coronar& sin0s *actate (ro+0ction

increases in some (atients1


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This in+icates a re%iona* mismatch ,et4een m&ocar+ia* o.&%en

s0((*& an+ +eman+1

R!SPIRATORY

3i"e the barbiturates! propofol is a profound respiratory depressant

that usually causes apnea follo$ing an induction dose.

4ven $hen used for conscious sedation in subanesthetic doses! propofol

infusion inhibits hypoic ventilatory drive and depresses the normal response

to hypercarbia.

#s a result! only properly trained personnel should use this techni&ue.

Propofol-induced depression of upper air$ay re'ees eceeds that of

thiopental and can prove helpful during intubation or laryngeal mas"

placement in the absence of paralysis.

A*tho0%h (ro(o)o* can ca0se histamine re*ease/ in+0ction 4ith(ro(o)o* is accom(anie+ 9 +isertai ,& a *o4er inci+ence o) 4hee:in%

in asthmatic an+ nonasthmatic (atients com(are+ 4ith ,ar,it0rates

or etomi+ate an+ is not contrain+icate+ in asthmatic (atients1

#!R!RAL

Propofol decreases cerebral blood 'o$ and intracranial pressure.

In (atients 4ith e*e3ate+ intracrania* (ress0re/ (ro(o)o* can ca0se a

critica* re+0ction in #PP 5; 0irin% a ,*oo+ (ro(o)o* concentration o)

?== n%9mL8 make it a (re)erre+ +r0% )or o0t(atient anesthesia1

5nduction is occasionally accompanied by ecitatory phenomena such as

muscle t$itching! spontaneous movement! opisthotonus! or hiccupping

possibly due to subcortical glycine antagonism.

#lthough these reactions may occasionally mimic tonicclonic sei6ures!

propofol appears to have predominantly anticonvulsant properties (ie! burst

suppression)! has been successfully used to terminate status epilepticus! and

may be safely administered to epileptic patients.

Propofol decreases intraocular pressure. Tolerance does not develop after

long-term propofol infusions.


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Dr0% Interactions

ondepolari6ing neuromuscular bloc"ing agents may be potentiated by

previous formulations of propofol! $hich contained *remophor. e$er

formulations do not share this interaction.

Fentan&* an+ a*)entani* concentrations may be increased byconcomitant administration of propofol.

ome clinicians administer a small amount of mi+a:o*am 5e%/ 6= @%9k%8

prior to induction $ith propofol9

they believe the combination produces synergistic e,ects (eg! faster onset

and lo$er total dose re&uirements). 0o$ever! this techni&ue of

:coin+0ction: has &uestionable e;cacy.

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