These are the pharmacological agent which when administered externally relieves mild or moderate pains without degree of consciousness called as Analgesics are worked against the pain so firstly introduced the Pain sensation.
2. • These are the pharmacological agent which when
administered externally relieves mild or moderate pains
without degree of consciousness called as Analgesics are
worked against the pain so firstly introduced the Pain
Define PAIN :
Pain is an unpleasant sensation which
inform about structural and functional changes
in body and act as warning signals against
3. 1. Superficial / cutaneous pain :
Arising from skin , superficial mucous membrane and nerve.
2. Deep , non-visceral Pain :
From muscle , joint ligaments
3. Visceral Pain :
It is diffused , not easily localized , is associated with sweating ,
nausea fall in B.P.
4. 1) Severe pain :
malignancy , burn
2) Mild Pain :
headache , Bodyach , arthralgia
, myalgia , neuralgia .
4. Referred Pain :
deep pain which may sometimes misinterpreted as if
it is coming from some part of the body other than actual site of
5. Psychogenic / Functional pain :
Vegue pain and not related to anatomical part of the body
5. Neurophysiology of Pain :
• Physiologically, pain occurs when
sensory nerve endings
called nociceptors (also referred
to as pain receptors) come into
contact with a painful or noxious
• The resulting nerve impulse
travels from the sensory nerve
ending to the spinal cord, where
the impulse is rapidly shunted to
the brain via nerve tracts in the
spinal cord and brainstem.
• The brain processes the pain
sensation and quickly responds
with a motor response in an
attempt to cease the action causing
6. (a) Naturally occurring opium alkaloid
e.g. Morphine , codeine
(b) semisynthetic derivatives :
e.g. Heroine , Dihydromorphine
(c) Synthetic Derivatives :
e.g. Pethidine and methadone
8. Phenanthreen Derivatives
Pharmacological action of drug :
• It is used as sulphate or hydrochoride , most important alkaloid in
• Morphine and It’s serrogates produced their major effect on CNS
1. On CNS :
(a) Analgesia :
• Morphine produced analgesia ,drowsiness , changes in mood and
mental clouding .
• Morphine , when administered , externally rilieves severe pain
associated with trauma , fracture , malignancy , burn , parturition,
acute pericardities , pleurisy .by the mechanism of
# To elevate the threshold for Painful stimulus.
# To alter the emotional reaction to pain .
Opioid (Narcotic ) analgesics
9. (b) Euphoria , Sedation , Hypnosis :
• morphine Produced sensation of well being called Euphoria .
If the drug is continuous to compelled it leads to addiction .
• Particularly in pain-free individual , it may produced sence of
anxiety and fear known as dysphoria.
• Sedation induced by morphine is charecterised by drowsiness ,
Decreased Physical activity ,difficult to concentration .
2) Respiration : Morphine Produced depression of
respiration by ,
• By direct depression action on brain steam respiratory centre.
• By reducing sensitivity of the medullary respiratory centre to
increase plasma CO2 concentration .
e.g. a man death from morphine , by due to respiratory attack .
10. 3) Pupil :
• Morphine and it’s surrogates cause constriction of pupil
( Miosis ) in man with characteristics pin point pupils .
• The MAO is due to action on Edlinger Westphal nucleus of
• Morphin produced pin point miosis.
• Miosis or myosis a medical term referring to excessive constriction
of the pupils, as a result of drugs or diseases.
11. 4) Nausea and Vomiting :
• It produced vomiting by stimulation of chemoreceptor trigger
zone (CTZ)in area of postrema medulla.
• Large dose , morphine depress the vomiting Centre . Thus in case
of morphine poisoning , vomiting is absent .
5) Cough :
• Morphine depress the cough reflex by directly depressinig
medullary cough center.
6) On GIT :
• Morphine reduces tone , motility , peristalsis of smooth
muscles of GIT , reduced all digestive enzymes and leads to constipation
Absorption, fate, Excretion of Morphine :
• When administered orally , absorption is slow and
• Morphine exist in Plasma , partly bound to plasma proteins
and partly free .
• It is conjugated with glucouronic acid and excreted through
Side Effect :
• Euphoria followed dysphoria .
• Mental clouding
• Nausea, vomiting
• Headache, Fatigue.
13. Therapeutic Uses / Applications :
1. For relief Pain
2. It is good analgesics to relieve severe types of pain associated
in Myocardial infarction, fracture of long bone , burns,
terrminal stage of malignancy , pulmonary embolism ,acute
3. Preanaesthetic agent
4. Valuable agent in acute left ventricular failure
5. Tincture of opium used for constipation .
• Tincture of Opium I.P. 0.3 to 2.0 ml orally
• Morphine sulphate injection , I.P. 10 mg ampoule
10 to 20 mg subcutaneously
14. Morphine should not be used in following condition ;
Head ach / brain injury
Undignosed abdominal pain
With phenothiazine mono amino oxidase inhibitors
In old patient and infant
15. Causes :
• Clinically overdoses
• Accidental or intentional overdosing
addiction by addict .
• Pin point miosis
• Respiratory depression
• Nausea and Vomiting
• Clammy , Pale skin
• If intoxication by mouth , gastric lavage is advised
• If respiration is badly hampered , artificially respiration is
(b) Drug treatment :
• Pure antagonist Naloxone
Trade name Narcan
Dose 0.4 mg I/V
• Partial antagonist Nalophine
Trade name Lethidrone
Dose 10 mg I/V
17. Codeine :
• Much less potent analgesic than morphine .
• No depression of respiration and less addiction liability .
• It is most commonly used as an antitussive .
• Devoid of Narcotics and analgesic activity .
• Has relaxant action on smooth muscle.
• Has significant anti-tussive action.
• It has wide application in therapy of cough .
Other Phenanthrene Alkaloid of Opium :
Benzyl Isoquinoline Alkaloids of Opium
18. Non-narcotic / Non opioid / NSAID/
Non narcotics analgesics are Non narcotics analgesics are drug which produced
relief from pain and lower elevated body temperature , the also possess anti-
1. Salicylic acid derivatives : e.g. Acetyl Salicylic
2. Para amimo phenol derivatives : e.g.
3. Pyrozole derivatives : e.g. Oxyphenbutazone
4. Indole derivatives : e.g. Indomethacin
19. Pharmacology of NSAID
Non-steroidal anti-inflammatory drugs (NSAIDs) such as aspirin and
diclofanac are the most commonly prescribed drugs for arthritis,
inflammation, and cardiovascular protection. However, they cause
gastrointestinal complications such as ulcers and erosions. The
pathophysiology of these complications has mostly been ascribed to NSAID’s
action on the cyclooxygenase (COX) inhibition and the subsequent
prostaglandin (PG) deficiency. Here’s some Pharmacology mnemonics.
Beneficial effects of inhibition of prostaglandin synthesis by NSAIDs (remember of
Arteriosus (NSAIDs for closure of patent ductus arteriosus)
20. 1. On respiration
Direct action on medullary respiratory Centre.
Indirect action by increasing plasma carbon-dioxide concentration.
2. On GIT :
Salicylates ingestion causes dyspepsia high incidence o nausea ,
vomiting , epigastric distress , belching , frank gastric bleeding and
3. On blood system :
Salicylates reduce platelets aggregation , promotes fibrinolysis
,prolongs bleeding time , interfere with the formation of endoperoxide
thromboxane, the chemical mediators essential for Platelets
Other Pharmacological action
21. 4. Uricosuric effect :
Salicylates in small dose 1 – 2 gm./day increase plasma urate level by
interfering urate secretion by distal tubules
Salicylates in large doses 5 mg/day inhibit reabsorption of urate by
proximal tubule .
This result urcosuria.
5. Hepatic and renal effect :
Increase secretion of bile
Large dose Acute hepatic necrosis
High dose Increase urine cell count , Tracess of albumin .
6 Metabolic effect :
Hyperpyrexia due to large dose .
22. Side effects of NSAIDs (remember of NSAID):
Damage of Stomach Wall (ulcer)
Impaired renal function