Induction agents iv anaesthesia

1. INTRAVENOUS
ANAESTHETIC
AGENTS
Dr. Med. Khaled Radaideh
Department of Anesthesiology - Jordan University of Science and
Technology Irbid-Jordan
March
23
1
Dr.
Med.
Khaled
Radaideh

2. INTRA VENOUS ANAESTHETIC AGENT
OBJECTIVES
1- Properties of the ideal intravenous anesthetic agent
2- Classification of the intravenous anesthetic agent
3- Sodium Thiopental
3.1. Definition
3.2. Classification
3.3. Physical chemical properties
3.4. Pharmacokinetics
3.5. Pharmacodynamics
3.6. Dose and Administration
3.7. Indication, contraindication and precautions
3.8. Side Effects
March
23
2
Dr.
Med.
Khaled
Radaideh

3. INTRA VENOUS ANAESTHETIC AGENT
OBJECTIVES
4- Propofol
4.1. Physical and chemical properties
4.2. Dosage
4.3. Effects on organ systems
4.4. Indication and contraindication
5. Ketamine
5.1. definition of dissociative anesthesia
5.2. Physical & chemical Properties
5.3. Pharmacokinetics (Route of administration and Dosage)
5.4. Metabolism
5.5. Mechanism of action
5.6. Pharmacodynamics (effect on organ systems)
5.7. Indications and contraindications
March
23
3
Dr.
Med.
Khaled
Radaideh

4. INTRA VENOUS ANAESTHETIC AGENT
OBJECTIVES
6- Benzodiazepines
6.1. Features
6.2. Mode of action
6.3. Midazolam and Diazepam (Uses, differences between
them)
6.4. Benzodiazepine antagonists (Flumazenil)
7. Narcotic Agonists
7.1. Origin, Site of action and Receptors
7.2. Pharmacokinetics
7.3. Pharmacodynamics (effect on organ systems)
5.4. Fentanyl And Morphine
8. Narcotic Antagonists (Naloxone)
March
23
4
Dr.
Med.
Khaled
Radaideh

5. PROPERTIES OF THE IDEAL INTRA
VENOUS ANAESTHETIC AGENT{1 OF 3}
1-rapid onset: achieved by an agent that is mainly :
A- un-ionized at blood ph(7.35 – 7.45)
B- highly lipid soluble
** these properties permit penetration of the BBB
2-rapid recovery:
-early recovery of consciousness is usually produced by rapid
redistribution of the drug from brain into other well-perfused tissues
particularly muscles
-plasma conc. Of drug decreases & drug diffuses out of the brain along a
conc. gradient
-quality of the recovery period is more related to the rate of metabolism
of the drug
* Drugs with slow metabolism are with a more prolonged hangover
effect (fatigue, weakness, pain, nuasea vomiting..etc )and accumulate
if used in repeated doses or by infusion for maintenance of anesthesia
March
23
5
Dr.
Med.
Khaled
Radaideh

6. 3- analgesia at sub anesthetic concentrations
*analgesia :an absence of the sense of pain without loss of consciousness
4- minimal cardiovascular and resp. depression
5- no emetic effects
6- no excitatory phenomena
e.g. coughing .hiccup ,involuntary movements
7-no emergence phenomena
e.g. nightmares
8-no interaction with neuromuscular blocking drugs(muscle relaxant)
*Neuromuscular blocking drugs relax skeletal muscles and induce paralysis.
PROPERTIES OF THE IDEAL INTRA
VENOUS ANAESTHETIC AGENT {2 of 3}
March
23
6
Dr.
Med.
Khaled
Radaideh

7. 9- no pain on injection
10- no venous sequelae(such as thrombosis)
11-no toxic effects on other organs
12- no release of histamine(bronchospasm
..itching)
13- no hypersensitivity reactions
14- water soluble formulation
15- long shelf life :
The length of time a product may be stored without becoming unsuitable
for use or consumption.
16-no stimulation of porphyria
PROPERTIES OF THE IDEAL INTRA VENOUS
ANAESTHETIC AGENT {3 of 3}
March
23
7
Dr.
Med.
Khaled
Radaideh

8. INTRAVENOUS ANAESTHETIC AGENTS
1- Barbiturate
1.1. sodium thiopental(used
for over 40 years)
2. Non barbiturate
2.1. propofol (newly
introduced)
2.2. ketamine (infrequently
used)
2.3. Etomidate
4. other adjuvant intravenous
anesthetic agents
(benzodiazepines,
midazolam, diazepam,…)
March
23
8
Dr.
Med.
Khaled
Radaideh

9. SODIUM THIOPENTAL (PENTOTHAL)
Definition:
ultra short acting barbiturate
Classification:
IV anesthetic-hypnotic
Physical chemical properties :
-It’s a Yellow powder with a sulphuric
smell and a bitter taste
-highly lipid soluble compound
-when combined with sodium
carbonate it becomes water soluble
March
23
9
Dr.
Med.
Khaled
Radaideh

10. SODIUM THIOPENTAL (PENTOTHAL)
-its bacteriostatic in water and has a
ph of 10.6 to10.8
-*when injected ,sodium bicarbonate
is neutralized and the thiopental is
converted to its lipid soluble non
ionazed form(40% ionized at
ph=7.4)
-its highly protien bound by
albumen(75%)
Which prevents precipition out of
solution in vivo
March
23
10
Dr.
Med.
Khaled
Radaideh

11. Supplied: thiopental(yellow powder) is
dissolved in water& sodium carbonate to
make a 2.5% solution (25mg/ml)
- -Its stable at room temp for 2 weeks
- Thiopental is a core medicine in the World
Health Organization's "Essential Drugs
List", which is a list of minimum medical
needs for a basic health care system
Sodium thiopental (pentothal)
March
23
11
Dr.
Med.
Khaled
Radaideh

12. SODIUM THIOPENTAL (PENTOTHAL)
Pharmacokinetics
-An IV dose of 3-5 mg/kg results in loss of
consciousness
-time required to render the patient unconscious
is generally
30-60 secs after administration .this is called the
“arm brain” circulation time
-arm brain circulation time
is the time required for the drug to pass from site of
injection to the brain as it passes through the right
heart ,pulmonary circ., and the left heart
March
23
12
Dr.
Med.
Khaled
Radaideh

13. Pharmacokinetics
-with no other drugs ,the anesthetic
state persists for 5-10 mins
Its concentration is low enough in
the brain such that
consciousness returns.
So is most commonly used in the
induction phase of general
anesthesia
As with all lipid soluble anesthetic
drugs, the short duration of action
of Sodium thiopental is almost
entirely due to its redistribution
away from central circulation
towards muscle and fat tissue.
Sodium thiopental (pentothal)
March
23
13
Dr.
Med.
Khaled
Radaideh

14. Pharmacokinetics
-sulphur containing drugs , acidosis, NSAIDS may displace
thiopental from albumen
-liver &renal disease may be associated with low albumin levels
so result in an increase in free thiopental which inc. the anesthetic
toxicity and potency
-metabolism occurs primarily in the liver with approximately 10 to
15%of the drug level metabolized per hour
-a desulfuration rxn in liver produces pentobarbital which under goes
oxidative metabolism yielding 2 compounds with no anesthetic
activity
-less than 1% of the drug is excreted unchanged in the urine
Sodium thiopental (pentothal)
March
23
14
Dr.
Med.
Khaled
Radaideh

15. SODIUM THIOPENTAL (PENTOTHAL)
pharmacodynamics
CNS:barbiturates interact with chloride ion channels by
altering the duration they spend in an open state
-this facilitates inhibitory neurotrasmitters such as gama amino
butyric acid(GABA)
As well as blocking excitatory NTM actions such as glutamic acid
-thiopental will decrease both cerebral electrical & metabolic activity
So it can be used to stop seizures activity in emergency
situations
-to maintain depression of cerebral electrical activity very high dose
are required
-But to maintian seizure control & avoid cv depression from high
dose of thiopental other drugs are used (e.g. benzodiazepines)
March
23
15
Dr.
Med.
Khaled
Radaideh

16. SODIUM THIOPENTAL (PENTOTHAL)
pharmacodynamics
CNS: Elevated ICP can quickly be reduced by
thiopental BUT The improvement of ICP requires high
dose of thiopental to be maintained
The reduction of ICP is due to cerebral vasoconstriction,
reduced cerb. Metabolism &oxygen requirments
associated with dec.cerebral blood volume
-theopental has an an anti-analgesic effect, since low
dose may decrease pain threshold
-Intraocular pressure decreases
up to 25% with 3-5mg/kg of thiopental and persists for
3 to 5 minutes
March
23
16
Dr.
Med.
Khaled
Radaideh

17. SODIUM THIOPENTAL (PENTOTHAL)
Pharmacodynamics
 CVS:-thiopental causes a dose related
depression of myocardial function as measured
by CO,SV, and blood pressure
-coronary blood flow, heart rate ,&myocardial oxygen
uptake all increase following thiopental
administration
-venous tone decreases (decreased preload)
And contributes to the increase in HR and decrease in
BP
-little change in total peripheral resistance
March
23
17
Dr.
Med.
Khaled
Radaideh

18. SODIUM THIOPENTAL (PENTOTHAL)
Pharmacodynamics
Respiratory:-induction of anesthesia with
thiopental may be associated with 2 or 3 large
breaths followed by apnea for less than 1min
-there is dose related depression of the
respiratory response to hypercarbia and
hypoxia
-laryngospasm and bronchoconstriction may
be associated with light levels of thiopental and
with airway manipulation or intubation
-FRC is reduced by 20% with induction of
anasthesia
>Functional Residual Capacity (FRC) is the volume of air
present in the lungs at the end of passive expiration.
March
23
18
Dr.
Med.
Khaled
Radaideh

19. SODIUM THIOPENTAL (PENTOTHAL)
Pharmacodynamics
 GI: enzyme induction may occur with
prolonged high dose therapy
- Hypoalbuminemia will result in an increase in
unbound (free) thiopental and an increase in
the potency of thiopental
 GU/pregnancy/fetus:
- Thiopental has little or no effect on the kidneys
or gravid uterus.
-although thiopental crosses the placenta
It has no significant effect on the fetus when
used for cesarean section (dose used is limited
to 4mg/kg)
March
23
19
Dr.
Med.
Khaled
Radaideh

20. SODIUM THIOPENTAL (PENTOTHAL)
Dose & administration
-the usual dose is 3-6 mg/kg
- Thiopental should be used with caution
for Patients suffering from shock status
because normal dose may lead to rapid
death
-for a short procedure (e.g.cardioversion) a
dose of 2 mg/kg is generally sufficient
-for frail elderly women with hip fracture .5-
1 mg/kg may induce anesthesia
March
23
20
Dr.
Med.
Khaled
Radaideh

21. SODIUM THIOPENTAL (PENTOTHAL)
INDICATIONS
1- induction of anesthesia
2- maintenance of anesthesia
for short procedures
3- control of convulsive states
4- for supplement of regional
anesthesia or low potency
anesthesia
March
23
21
Dr.
Med.
Khaled
Radaideh

22. SODIUM THIOPENTAL (PENTOTHAL)
Absolute contraindications
1- airway obstruction
2- porphyria
3- previous hypersensitivity
PRECUATIONS
1- CVS disease
2- severe hepatic disease
3- renal diseases
March
23
22
Dr.
Med.
Khaled
Radaideh

23. SODIUM THIOPENTAL (PENTOTHAL)
SIDE EFFECTS
1- hypotension :if thiopental is administered to
hypovolemic, shocked or previously hypertensive pt
2- respiratory depression :when excessive doses are
used
3- tissue necrosis : following venous infusion
4- laryngeal spasm
5- bronchospasm :unusual but may be precipitated in
asthmatics pts
6- allergic reaction : from cutanous rashes to severe
anaphylactic shock with cvs collapse
March
23
23
Dr.
Med.
Khaled
Radaideh

24. SODIUM THIOPENTAL (PENTOTHAL)
SIDE EFFECTS
7- Rarely, intra-arterial injection can occur.
The consequences of accidental arterial injection may be
severe.
The degree of injury is related to the concentration of the drug.
Treatment consists of
1. dilution of the drug by the administration of saline into the
artery,
2. heparinization to prevent thrombosis, and
3. brachial plexus block.
Overall, the proper administration of thiopental intravenously is
remarkably free of local toxicity.
March
23
24
Dr.
Med.
Khaled
Radaideh

25. March
23
25
Dr.
Med.
Khaled
Radaideh

26. PROPOFOL
 Intravenous
anaesthetic/hypnotic.
 Akylphenol.
 Propofol is a sweet drug
in the OR, but definitely
not for home use.
March
23
26
Dr.
Med.
Khaled
Radaideh

27. PROPOFOL
PHYSICAL AND CHEMICAL PROPERTIES
Emulsion consists of:
1% propofol 10mg/ml
10% soyabean oil.
2.25 %glycerol
1.2% purified egg phosphatide.
March
23
27
Dr.
Med.
Khaled
Radaideh

28. PROPOFOL
PHYSICAL AND CHEMICAL PROPERTIES
 so Propofol is a highly lipid soluble oil that’s combined
with glycerol, egg, and soya bean oil for IV
administration.
 It’s appearance is similar to that of a 2% milk.
 It has a pH of 7 and is supplied in 20 ml ampoules
with a concentration of 10 mg/ml.
 Neither precipitates histamine release nor triggers
malignant hyperthermia.
 Has no effects on muscle relaxants.
 Associated with low incidence of nausea & vomiting.
March
23
28
Dr.
Med.
Khaled
Radaideh

29. PROPOFOL
DOSAGE
 For healthy unpremedicated 2.5-3 mg/kg.
 For premedicated 1.5-2 mg/kg.
 Elderly patients <= 1 mg/kg.
 Maintenance of anesthesia (50-150 mcg/kg/min)
combined with N2O and Opioids (Continuous
Infusion: Total intravenous Anesthesia TIVA)
 For IV conscious sedation for operative procedures
with local anaesthesia 25-75 mcg/kg/min.
March
23
29
Dr.
Med.
Khaled
Radaideh

30. PROPOFOL
EFFECTS ON ORGAN SYSTEMS
Cerebral:
decreases cerebral blood flow and intracranial
pressure. Propofol has antiemetic, antipruritic,
and anticonvulsant properties.
Cardiovascular:
decrease in arterial blood pressure secondary to a
drop in systemic vascular resistance,
contractility, and preload. Hypotension is more
pronounced than with thiopental. Propofol
markedly impairs the normal arterial baroreflex
response to hypotension.
March
23
30
Dr.
Med.
Khaled
Radaideh

31. PROPOFOL
EFFECTS ON ORGAN SYSTEMS
Respiratory:
propofol causes profound respiratory depression.
Propofol induced depression of upper airway
reflexes exceeds that of thiopental.
Venous irritation:
 Pain on injection is more common than with thiopental
esp. if given in a small vein in the hand.
 To solve this problem:
1. small doze of lidocaine with propofol.
2. administering propofol through a fast flowing more proximal IV
catheter.
March
23
31
Dr.
Med.
Khaled
Radaideh

32. PROPOFOL
INDICATIONS
indication Approved Patient Population
Initiation and maintenance of
Monitored Anesthesia Care
sedation
Adults only
Combined sedation and regional
anesthesia
Adults only
(See PRECAUTIONS)
Induction of General Anesthesia Patients ≥ 3 years of age
Mainenance of General Anesthesia Patients ≥ 2 months of age
Intensive Care Unit (ICU) sedation
of intubated, mechanically
ventilated patients
Adults only
March
23
32
Dr.
Med.
Khaled
Radaideh

33. PROPOFOL
CONTRAINDICATIONS
1. Egg allergy.
2. Lack of resuscitation equipment or
knowledge of the drug.
3. Inability to maintain a patent airway.
4. Conditions in which reduction in blood
pressure can’t be tolerated. E.g. patients with
fixed cardiac output (severe aortic or mitral
stenosis, IHSS, pericardial tamponade) and
those in shock status.
March
23
33
Dr.
Med.
Khaled
Radaideh

34. KETAMINE
 It’s a dissociative anesthetic
agent.
 by dissociative we mean that
the patient is unconscious but
appears awake and doesn’t
feel pain.
 It has anesthetic and
analgesic effect
March
23
34
Dr.
Med.
Khaled
Radaideh

35. KETAMINE
PHYSICAL & CHEMICAL PROPERTIES
March
23
35
Dr.
Med.
Khaled
Radaideh
chemically related to the psychotropic
drug ( e.g. phencyclidine).
Water soluble, and 10x more lipid
soluble than thiopental.
pH=3.5 - 5.5

36. KETAMINE
PHARMACOKINETICS
ROUTE OF ADMINISTRATION
I.V. : 2mg/kg
IM.
Oral.
Rectal. Needs higher doze due to
extensive first pass metabolism and
decreased absorption.
March
23
36
Dr.
Med.
Khaled
Radaideh

37. KETAMINE
PHARMACOKINETICS
DOSAGE
 IM  5 – 10 mg/kg. peak plasma level
reach approx 15 minutes
 IV  1 – 2 mg/kg. dissociated stage is
noted in 15 seconds. intense analgesia,
amnesia & unconciousness occur within 45-
60 minutes
subsequent IV doses of 1/3 – ½ of the
initial dose maybe required
March
23
37
Dr.
Med.
Khaled
Radaideh

38. KETMINE
METABOLISM
 It has a rapid absorption and distribution to the
vessel rich groups like THIOPENTAL
 Hepatic metabolism is required for elimination
 <5% excreted unchanged in urine
March
23
38
Dr.
Med.
Khaled
Radaideh

39. KETMINE
MECHANISM OF ACTION
 There are 3 theories explains the MOA of ketamines :
1 – N-methyl aspartate receptor theory :
NMA receptors may represent a subgroup of the sigma opiate
receptors (the PCP site) that blocks spinal pain reflexes.
2 – Opiate receptor theory :
Ketamine may have some affinity for opiate receptors but it’s
effect can’t be reversed with naloxone.
3- Miscellaneous receptor theory :
It reacts with muscarinic, cholinergic and serotonergic receptors.
 Ketamine is a potent analgesic at subanesthetic plasma
concentrations.
 It has a wide margin of safety ( up to 10x the usual dose )
March
23
39
Dr.
Med.
Khaled
Radaideh

40. KETMINE
PHARMACODYNAMICS
 CNS :
1. ketamine increases cerebral oxygen
consumption, cerebral blood flow, and
intracranial pressure
2- generalized increase in the muscle tone and
purposful movements.
3- Unpleasant dreams, hallucinations or frank delirium
(esp. females & large doze of ketamine).
incidence of dilirium in 15-35 year old pts is approx.
20%
March
23
40
Dr.
Med.
Khaled
Radaideh

41. KETMINE
PHARMACODYNAMICS
Respiratory system:
It preserves laryngeal &pharyngeal airway reflexes.
• Ketamine is a potent bronchodilator.
• The CO2 response curve is shifted to the left with its
slope unchanged (similar to opiates).
 FRC  unchaged.
 Minute ventilation  unchanged.
 Tidal volume  unchanged.
 Hypoxic pulmonary vasoconstriction  unchanged.
 Ketamine causes increased secretions but this can be
limited by anti-cholinergic drugs.
March
23
41
Dr.
Med.
Khaled
Radaideh

42. KETMINE
PHARMACODYNAMICS
CVS:
• It produces central sympathetic stimulation,
which increases:
1. arterial blood pressure, heart rate, and cardiac
output.
2. Pulmonary artery pressure.
3. Coronary blood flow.
4. Myocardail oxygen uptake.
It may cause myocardial depression if the
sympathetic nervous sys is exhausted or
blocked.
March
23
42
Dr.
Med.
Khaled
Radaideh

43. KETMINE
PHARMACODYNAMICS
GI
 Minimal anorexia, nausea & vomiting.
GU
Placental transfer does occur, but neonatal depression hasn’t
been observed if the doze is limited to < 1 mg/kg.
Muscle system
 Generalized increase in skeletal muscle tone.
 Increases the effects of muscle relaxants.
Endocrine Sys.
 Increased sympathetic stimulation  increased blood
glucose, increased plasma cortisol, increased heart rate.
March
23
43
Dr.
Med.
Khaled
Radaideh

44. KETMINE
INDICATIONS
1- sole anesthetic for diagnosis and surgical
procedures
2- induction of anesthesia
3- to supplement regional or local anesthetic
techniques
4- for anesthetic induction in severe asthmatic pts. Or
patients with cardiovascular collapse requiring
emergency surgery
March
23
44
Dr.
Med.
Khaled
Radaideh

45. KETMINE
CONTRAINDICATIONS
1- lack of knowledge of the drug
2- lack of resuscitative equipment
3- inability to maintain a patent airways
4- allergy to ketamine
5- history of psychosis
6- cerebro-vascular disease
7- Patients. For whom hypertention is hazardous
March
23
45
Dr.
Med.
Khaled
Radaideh

46. BENZODIAZEPINES
Features which result in their
popularity as adjuvant IV anaesthetic
agents:
1 – amnesia
2 – minimal cardiarespiretory
depressant effect.
3 – anticonvulsant activity.
4 – low incidence of tolerance and
dependence.
March
23
46
Dr.
Med.
Khaled
Radaideh

47. BENZODIAZEPINES
MODE OF ACTION
1 – They inhibit the actions of glycine (by increasing
the conc. Of a glycine inhibitory neurotransmitter)
which will lead to antianxiety and skeletal muscle
relaxant effects.
2 – They facilitate the actions of the inhibitory
neurotransmitter GABA which results in the
sedative and anticonvulsant effects.
 Benzodiazepines are highly lipid soluble.
 They are highly protein bound (albumin).
 They are metabolized by the liver through conjugation with
glucoronic acid and excreted by the kidneys.
 Midazolam and Diazepam are the most commonly used
benzodiazepines during operative procedures.
March
23
47
Dr.
Med.
Khaled
Radaideh

48. BENZODIAZEPINES
MIDAZOLAM AND DIAZEPAM
 They are commonly used to provide:
1- IV sedation.
2- amnesia.
3- reducing anxiety.
March
23
48
Dr.
Med.
Khaled
Radaideh

49. BENZODIAZEPINES MIDAZOLAM AND DIAZEPAM
THE DIFFERENCES BETWEEN THEM
1- Midazolam is 2-3 times more potent than
diazepam:
2- The dose for IV conscious sedation: 0.5 – 3
mg up to 0.1 mg/kg for midazolam, and 1-10
mg for diazepam.
3- The dose for inducing anesthesia: 0.2 – 0.4
mg/kg for midazolam , and 0.15-1.5 mg/kg for
diazepam.
4- Midazolam has a more rapid onset, greater
amnestic effect, less postoperative sedative
effects than diazepam.
March
23
49
Dr.
Med.
Khaled
Radaideh

50. BENZODIAZEPINES MIDAZOLAM AND DIAZEPAM
THE DIFFERENCES BETWEEN THEM
5- Pain on injection and subsequent
thrombophlebitis is less likely with midazolam
(an emulsion of diazepam)
6- Midazolam is more costly than diazepam).
7- Midazolam’s duration of action is less than
diazepam but almost 3 times that of thiopental.
8- Elimination half time for midazolam range from
1-4 hours, and for diazepam from 21-37 hours.
9- Midazolam is supplied as a clear liquid in
concentrations of 1-5 mg/ml.
March
23
50
Dr.
Med.
Khaled
Radaideh

51. BENZODIAZEPINE ANTAGONISTS (FLUMAZENIL)
 It’s an imidazobenzodiazepine.
 It specifically antagonizes benzodiazepine’s central
effects by copetative inhibition.
 It’s elimination half-time is one hour, considerably less
than most benzodiazepines; therefore we will need
repeated administrations of flumazenil to antagonize a
benzodiazepine with a longer half-time.
March
23
51
Dr.
Med.
Khaled
Radaideh

52. BENZODIAZEPINE ANTAGONISTS (FLUMAZENIL)
 Flumazenil is supplied as a colourless liquid in a
concentration of 0.1 mg/ml.
 The usual initial dose is 0.2 mg over 15
seconds, if the desired level of consiousness is
not obtained within one minute of administration
we can give repeated doses of 0.1 mg every
minute up to the maximum of 2 mg, and if
sedation recurs we can use infusions of 0.1-0.4
mg/hour.
 Flumazenil is well tolerated.
 The most common side is nausea (4% of
patients).
March
23
52
Dr.
Med.
Khaled
Radaideh

53. NARCOTIC AGONISTS
Opium derived
from dried juice of
poppy plant which
contains over 20
plant alkaloids.
including morphine
& codiene.
March
23
53
Dr.
Med.
Khaled
Radaideh

54. NARCOTIC AGONISTS
SITE OF ACTION
 Opioid receptors are predominantly located in the:
1. Brain stem (amygdala, corpus striatum,
periaqueductal gray matter and medulla).
2. Spinal cord(substantia gelatinosa).
3. GIT.
 They act on 3 types of receptors:
1. Mu receptors (μ): analgesia, respiratory
depression, euphoria, & physical dependence.
2. Kappa receptors (K): analgesia, sedation,
respiratory depression, miosis.
3. Segma receptors(a): dysphoria, hallucination,
tachypnea, tachycardia.
March
23
54
Dr.
Med.
Khaled
Radaideh

55. NARCOTIC AGONISTS
PHARMACOKINETICS
Rapid distribution through the body
following IV injection.
It’s metabolized by the liver and the
majority of the inactive metabolites are
excreted unchanged in the urine.
March
23
55
Dr.
Med.
Khaled
Radaideh

56. NARCOTIC AGONISTS
PHARMACODYNAMICS
CNS:
Opioids sedate through interfering with
sensory perception of painful stimuli.
large doses produce unconsciousness but
they are generally incapable of producing
anesthesia and it can’t guarantee total
amnesia.
It may produce nausea & emesis through
stimulation of the chemoreceptor trigger
zone.
March
23
56
Dr.
Med.
Khaled
Radaideh

57. NARCOTIC AGONISTS
PHARMACODYNAMICS
Respiratory
They result in dose related depression
of respiratory rate and minute
ventilation and increase the tidal
volume which will lead to a slow deep
respiration. Reversed by naloxone
administration.
March
23
57
Dr.
Med.
Khaled
Radaideh

58. NARCOTIC AGONISTS
PHARMACODYNAMICS
CVS
 Opioids have little myocardial depressant effect even
when administered in high doses.
 Supplementation with either N2O or benzodiazepines
may depress cardiac output.
 They decrease systemic vascular resistance either by
decreasing sympathetic outflow or by releasing
histamine (as morphine) which produces vasodilation
& decrease SVR.
 Synthetic opioids are less likely to release histamine.
 They produce bradycardia by stimulation vagal
nucleus in the brain stem.
March
23
58
Dr.
Med.
Khaled
Radaideh

59. NARCOTIC AGONISTS
PHARMACODYNAMICS
GIT
 Narcotics slow GI mobility and may result in
constipation or post operative ileus.
 All narcotics increase biliary tract tone which
may lead to biliary colic with patients with bile
stones.
Others
 Increases the bladder sphincter’s tone  urine
retention.
 Anaphylactic reactions, bronchospasm, chest
wall rigidity and pruritis.
March
23
59
Dr.
Med.
Khaled
Radaideh

60. NARCOTIC AGONISTS
FENTANYL AND MORPHINE
Fentanyl is the most narcotic agent used
during induction of anaesthesia due to its
rapid onset (highly lipid soluble) and
predictable duration of action (30
minutes).
Morphine is used in the perioperative
period to provide long lasting analgesia.
And it should be administered slowly at a
rate < 5 mg/min to avoid excessive
histamine release.
March
23
60
Dr.
Med.
Khaled
Radaideh

61. NARCOTIC AGONISTS
FENTANYL AND MORPHINE
Low dose
Analgesic dose
Potency Ratio
0.05 - 0.2 mg/kg
10 mg
1
Morphine
0.5 – 3 mic g/kg
100 mcg
100
Fentanyl
March
23
61
Dr.
Med.
Khaled
Radaideh

62. NARCOTIC ANTAGONISTS (NALOXONE)
 Naloxone competes with opioids at the mu, delta,
kappa and sigma receptors.
 Ampules of 0.02, 0.4 and 1 mg/ml.
 Peak effect 1-2 min.
 Duration of action 30-60 min.
 Used in perioperative surgical patients with excessive
sedation or respiratory sedation secondary to
opioids.
March
23
62
Dr.
Med.
Khaled
Radaideh

63. NARCOTIC ANTAGONISTS (NALOXONE)
 Given in small incremental doses.
 High doses of naloxone will result in sudden
reversal of analgesic effects leading to abrupt
return of pain resulting in hypertension,
tachycardia, pulmonary edema, ventricular
dysrhythmias and cardiac arrests.
 If sedation or respiratory depression recurs,
continuous infusion of 3-10 micg/kg/hour of
naloxone is required.
March
23
63
Dr.
Med.
Khaled
Radaideh

64. ANAESTHESIA
THANK YOU
March
23
64
Dr.
Med.
Khaled
Radaideh

65. INTRAVENOUS
ANAESTHETIC
AGENTS
Thank you
Dr. Med. Khaled Radaideh
Department of Anesthesiology - Jordan University of Science and Technology Irbid-Jordan
March
23
65
Dr.
Med.
Khaled
Radaideh