Analgesics are drugs that relieve pain without causing unconsciousness. Opiates are obtained from the opium poppy and act on opioid receptors in the central nervous system and tissues. There are three main types of opioid receptors that are involved in analgesia, respiratory depression, and euphoria. Opioid analgesics include natural, semisynthetic, and synthetic drugs and can be classified as agonists, antagonists, or mixed agonist-antagonists. Morphine is a potent agonist that binds to opioid receptors, decreasing substances involved in pain transmission and producing analgesia, euphoria, respiratory depression, constipation and other effects. It is metabolized in the liver and excreted in urine.

1. ANALGESICS
Analgesics are the drugs which relieve pain withoutCausing
loss of Consciousness.
Opiates:
Opiates means product obtained from theOpium poppy.
Opioid Analgesics:
Opioid Analgesics are the naturally.Occuring, semi-synthetic
and synthetic drugs a morphine like action.
Eg: relief of pain and depression of CNS.

2. Norcotic Analgesics:
It is an old term for opioid Analgesics
Opioid Receptors:
Morphine and Other Opioids act through
specific receptors present in the CNS and
peripheral tissues.

3. The following 1M (mu). are the Opioid Receptors analgesia (supraspinal).
Respiratory depression, euphoria. Sedation and physkal
dependence as a fie 2) k (kappa): analgesia (spinal), dysphoria Sedation
3) S (delta): analgesia (spinal and a effective Component of supraspinal) and em
and emotional behaviour.

4. classification
Agonist
a) Natural - Morphine Coolere
b) Synthetic- Antagonist Pethidine, Methadone
Naloxone, Naltrexone
MixedAgonist Antagonist
Nalorphine Buprenorphine.Pentazocine, Butorphanol, Morphine

5. MOA:
Morphine
↙↓↘
Binds to Opiate Receptors ↑ k channelCachannel
(m,k,s)
↓ ↓ ↓
adenylaticyclasHyperpolarisationintracellular ca
↓ ↓↙
CAMPDecrease the release.of Substance that are involved in pain

6. Pharmacological Actions:
1. Analgesia
Morphine reliever severe pain like Visceral pain and pain of trauma. It produces sleep
which also elevates the threshold.
CNS
Morphine produces euphoria in presenceof pain with increased dose, it produce sleep
3) Respiration:
Morphine produces depression of Respiration
4) Pupil
It Produce Constriction of pupil. This effect is blocked by atropine. morphine addicts
have constricted pupil (pin pant pupil)
Emitic ActionIn Small doses, morphine produces Vomiting due to stimulation of
(CTZ).
6) Antitussing
Morphine suppresses cough by depressing the cough Center.
Adhsecreation :
morphine produces release of ADH Thisresult is decrease of Urinary output.
8) GIT
It decreases peristalicpropulsivemovementsAll these leads to constipation
9) CVS
Normal dose of morphine produces no effect on heart • But hypotension may be
produced at toxic dose

7. pharamacokinetic
A - Absorption of morphine from GIT IS slow and in complete. quick effect is produced on subcutaneous injection.
D - It is partly bound to plasma proteins
M-metabolised by conjugation with glucuronic acid.
E-excreted in wine within 24 hours.
Preparation and dose
1. Tincture opium-0.3 to 2 ml by mouth.
2. morphinesulphate 2-8 to 20mg by mouth.
3 Morphine hydrochloride) or by injection.
Adr:
1) Central effect like dysphoria and mental clouding.
2) GIT symptoms like nausea, vomiting Constipation
3) Intolerance like tremor, delirium, and skin rashes
4) Acute morphine poisoning characterised by respiratory depression. pin point pupil, cyanosis, reduced body temperature,
hypotension shock and coma.
5) Depression of foetal respiration. b) Tolerance and drug dependence.
Uses
As an analgesic for the relief of severePain
2) For producing sedation and sleep
3) As pre- anaesthetic medication
4) In the treatment of acute leftVertricular failure.As the treatment an Antitussive.ofdiarrhoea.