This document discusses various opioid analgesic drugs, including both natural and synthetic opioids. It describes how opioids act through mu, kappa, and delta opioid receptors in the central nervous system and peripheral tissues to produce analgesia, respiratory depression, and other effects. The document categorizes common opioids like morphine, codeine, heroin, pethidine, fentanyl, methadone, and tramadol. For each opioid, it provides details on pharmacological effects, metabolism, excretion, preparations, doses, uses, and adverse drug reactions.

1. OPIOID ANALGESIC
DR.NADIRA SULTANA
PHARM.D

2. Analgesic
 Are drugs which relieve pain without causing
loss of consciousness
 OPIATES: product obtained from the opium
poppy.
 OPIOID ANALGESIC: naturally occurring
semi synthetic or synthetic drugs which have
action of relief of pain and depression of CNS.
 NARCOTICS ANALGESIC: old term for
opioid analgesic

3. Opioid receptors
 These opioid acts through receptors
present in CNS and pheripheral tissue.
 Following and there functions
1) µ(mu) : analgesia (supraspinal) ,
respiratory depression, euphoria ,sedation
and physical dependence
2) k(kappa) : analgesia (spinal),
dysphoria , sedation
3) δ delta : analgesia( supraspinal and
spinal )and emotional behaviour

4. CLASSIFICATION OF
OPIOID
NATURAL OPIUM
ALKALIODS
a) phenanthrene derivatives
b) benzylisoquinoline derivatives
Morphine , Codeine
Thebaine
Papaverine
Noscapine
Semisynthetic derivative Heroin
dihydromorphine
apomorphine
Synthetic substitutes Pethidine
methadone
fentanyl
tramadol

5. MORPHINE
Natural opium alkaloid
Opium is the milky exudate of unripe capsules of
the poppy plant (Papaver somniferum)
Classified into
Phenanthrene group : morphine , codeine,
thebaine
Benzylisoquinoline group : papaverine,
noscapine and narcine

6. Pharmacological action
 ANALGESIC : relieves severe pain like visceral
pain and pain of trauma
mechanism
1) it elevates the pain stimulus
2) alters emotional reaction to pain
3) produce sleep
 CNS : in presence of pain it produces euphoria , absence
of pain produces dysphoria. Increased dose produce
sleep
 Respiration: depression of respiration by
a) directly depressing the respiratory centre
b) decreasing the sensitivity of respiratory centre to CO2

7.  Pupil : constriction of pupil. This effect will block by
atropine. ..addicts have constricted pupil
 Emetic action : in small doses produce vomiting due to
stimulation chemoreceptor trigger zone . In large doses
morphine inhibits vomiting.
 Antitussive effect: suppresses cough by depressing
cough center
 ADH secretion: release of ADH which results in
decrease in urine output
 GIT: decreases peristaltic movements .
It produces spasm of intestinal smooth muscles and
spincters .It increases the absorbtion of water leads to
constipation
 CVS : normal dose – no effect
toxic dose produces hypotension

8. Absorption, fate and excretion
 Absorption from GIT is slow and incomplete.
 Quick effect on subcutaneous inj
 Metabolised by conjugation with glucuronic acid
 Excreted in urine within 24hours

9. preparation and dose
 1) Tincture opium – 0.3 to 2ml by
mouth
 2) Morphine sulphate - 8 to 20mg by
mouth or injection
 3) Morphine hydrochloride - 8 to 20mg
by mouth or injection

10. ADR
 CNS: dysphoria and mental clouding
 GIT: nausea, vomit, constipation
 Tremor, delirium, skin rshes
 Acute morphine poisoning- respiratory
depression, miosis, cynosis, reduced body
tempertaure, hypotension,shock and coma
 Depression of foetal respirtion
 Drug dependence

11. uses
 Analgesic
 Treat diarrhoeas
 Sedation
 Pre aneasthetic medication
 Acute left ventricular failure
 antitussive

12. Codeine
 It is phenanthrene alkaloid.
 It has antitussive effect..used to treat
cough, nausea, vomiting, miosis,
addiction are less with codeine.
 Less potent analgesic when compared
to morphine

13. PETHIDINE
 Synthetic compound
It produces same as morphine
1) analgesic effects
2)spasmogenic effect on smooth muscles and
spincters
3) nausea and vomtting
4)sedation and euphoria
5)respiratory depression
But pethidine does not produce miosis and anti
tussive effect

14.  Absorption : well on oral and parenteral.
 Metabolised : liver
 Excrete : urine
 ADR: local irritation on parentral administration
dry mouth, nausea, vomiting
euphoria, dysphoria, coma, convulsions
weakness, palpitation, respitaory depression
depression of foetal respiration
addiction and tolerance
 Preparation and dose:
1) pethidine hydrochloride tablets: 25 to 100mg
2) pethidine hydrochloride inj : 25 to 100mg by
subcutaneous or i.m inj and 25 to 50mg by i.v
inj

15. Fentanyl
 Pethidine congener
 It is 80 to 100 times more potent than morphine.
 Highly lipid soluble. So it enters brain easily.
 Peak analgesic effect produced in 5 min after
inj.
 Duration of action slow.
 Used as neuroleptanalgesia

16. Methadone
 Synthetic opioid
 It has analgesic effect, depressant, emetic
similar to morphine
 Used in opioid dependence
 Mechasim : it acts in tissues
 On discontinuation it is slowly released from
tissues. Mid withdrawal symptoms are mild

17. Tramadol
 It is centrally acting analgesic.
 Use for post operative pain, chronic pain, labour
pain
 Addiction is low