CNS Morphine Flashcards
Define analgesic
The drug which relieves pain of any origin is called analgesic
Classify analgesic
1)OpoidalNarcotic analgesic
2)Non opoidal ? Non narcotic analgesic
Opoidal? Narcotic analgesic
Morphine
Pethidine
Tramadol
Fentanyl
Pentazosine
Methadone
Nalbuphine
Non opoidal ? Non narcotic analgesic
Paracetamol
Aspirin
Diclofenac
Ketorolac
Aceclofenac
Ibuprofen
Indomethasin
Naproxen
Tenoxicam
Classification of opoidal analgesic
Acc to sources : natural , semi synthetic , synthetic
Acc to efficacy : low efficacy , high efficacy
ACC to source
NATURAL = morphine , codeine , endorphins , dynorphine , enkephaline
SEMI SYNTHETIC = Diamorphine , Dihydrocodeine , Hydrocodeine , Oxycodeine , Oxymorphine
SYNTHETIC = Pethidine , Fentanyl , pentazosine , Nalbuphine , Loperamide
ACC TO EFFICACY
HIGH EFFICACY = Morphine , Pethidine , Tramadol , Fentanyl , Diamorphine
LOW EFFICACY = Codeine , Dihydrocodeine , Pentazocine, Nalbuphine
Properties of narcotic / opoidal / morphine
They act in CNSS
Causes CNS depression (narcosis )- sedation
Active in visceral pain
Highly potent analgesic
No anti inflammatory and anti pyretic action
Can be used in labour pain
They have low TI
Chance of addiction , dependence
Pharmacological action of morphine
CNS EFFECTS
Analgesia , Sedation , Respiratory depression , Nausea and Vomitting , Cough suppression , Hyperthermia , Euphoria , Miosis
PERIPHERAL EFFECTS
Bradycardia , Constipation , increased biliary pressure , Urinary retention , Oliguria , Prolong labour , Warming and itching of skin , Galactorrhoea
Clinical uses of morphine
1)Diagnosed visceral pain = pancreatitis , pericarditis , pleurisy , cholecystitis , pyelonephritis
2) Post operative pain
3)Cancer pain
4) Burn pain
5) MI
6) Acute LVF
7) Cough suppression
8)Spinal anaesthesia (I/v0
A/ e of Morphine
Nausea
Vomitting
Respiratory depression
Cough suppression
Shivering
Warming
Itching
Sedation
Miosis
Constipation
Urinary retention
Oliguria
Orthostetis hypotension
Hypotension
Bradycardia
Euphoria
Dependence
Addiction liability
Contraindications of Morphine
1) Undiagnosed acute abdomen
2) Bronchial asthma
3)Pregnancy
4)Head. Injury
5)Convulsive disorder
6)Biliary colic
7) Acute renal failure
Why morphine contraindicated in undiagnosed visceral pain?
Morphine relieve visceral pain but proper diagnosis is not possible so complication may be developed ( rupture of viscera may occur ).
Morphine contraindicated in pregnancy
Morphine crosses blood placental barrier and may cause foetal respiratory depression and intrauterine foetal death may occur
Morphine is contraindicated in head injury
C/ F of head injury = vomitting, bradycardia , pin point pupil
Morphine also causes Vomitting , bradycardia , pin point pupil
So diagnosis and prognosis is difficult
Morphine is contraindicated on bronchial asthma
Morphine releases histamine from mast cell which causes bronchoconstriction and aggravation of bronchial asthma
Why Pethidine preferred in labour pain
Morphine crosses placenta and cannot metabolised so it has more duration of action and more chance of respiratory distress.
Pethidine rapidly metabolised in the placenta , less chance of foetal respiratory distress
M/A of morphine
Morphine/ Pethidine
1) Acts in presynaptic nerve terminal by bind with opoidal receptors ( meu , kappa , delta ) ==> Closing of Ca++ channel and NT release ( Glutamate ,Ach , NA, substance P) ==> Analgesic action
2) Acts in post synaptic terminal by bind with opoidal receptor ( meu) ==> opening of K+ channel ==.> Increase K+ conductance ==> hyperpolarization ==> blocking of pain pathway ==> Analgesic action
Diff between morphine & Pethidine
Morphine = natural / P= synthetic
M= more potent ( 10 times ) / P= less potent
Duration of action 4_ 6 hrs / / 2- 3 hrs
Effect on eye = Miosis // Mydriasis
Not use in pregnancy // used
Atropine like effect present // absent
Tolerance develops quickly // slowly
Addiction liability more // less
Opoidal receptors are
μ
δ
κ
