Analgesics are medications used to relieve pain without reducing consciousness. Opioid analgesics are very potent prescription medicines chemically related to morphine that are prescribed for moderate to severe pain. Morphine is the most important alkaloid of opium and produces analgesia through actions in the brain and spinal cord. It is readily absorbed from the GI tract, subcutaneous tissue, and muscle and is administered intravenously, epidurally, and intrathecally to relieve moderate to severe pain. Adverse reactions include confusion, anxiety, nausea, vomiting, constipation, urinary retention and respiratory depression.

1. ANALGESICS
By: Sathish Rajamani

2. INTRODUCTION
Analgesics are medications used to
relieve pain without reducing the
consciousness of the patient.
They work by reducing the amount of
pain felt and this is generally achieved
by interfering with the way the pain
message is transmitted by the nerves.
Analgesics will not treat the cause of
the pain but they will provide temporary
relief from pain symptoms.

3. TYPES OF ANALGESICS

4. OPIOID ANALGESICS
The opioid analgesics which are
prescription only medicines that are very
potent, being chemically related to
morphine.
Opioid analgesics are prescribed for
moderate to severe pain, particularly of
visceral origin, and are used in step two
and step three of the analgesic ladder.

5. Dependence and tolerance are well
known features with regular use
although this should not inhibit
prescribing in palliative care.
Some chronic non-malignant
conditions benefit from analgesic
control with opioids, but patients
should be reviewed regularly.

6. OPIUM, the greek name for poppy juice. Is
obtained from the juice of the papaver
somniferum.

7. ACTIONS OF OPIOID
ANALGESICS
Opioid analgesics interacts with four
major receptors in the CNS
Mu receptors
Kappa receptors
Sigma receptors and
Delta receptors

8. RECEPTORS EFFECTS
MU Analgesia, Respiratory
depression and euphoria
KAPPA Respiratory depression,
sedation
SEGMA Hallucination, Dysphoria,
Seizures
DELTA Analgesia

9. CLASSIFICATION OF OPIOID
ANALGESICS
Natural Alkaloids
 Morphine
 Codeine
Semi Synthetic Compounds
 Pethidine
 Methadone
 Tramadol

10. MORPHINE
Morphine is the most important alkaloid
of of opium.
Morphine produces analgesia through
actions in the brain and spinal cord.
Morphine is readily absorbed from the
GI tract and subcutaneous and muscle
tissue.
Morphine is administered
intravenously, epidurally, and
intrathecally.

11. PHARMACOTHERAPEUTICS
Morphine sulfate is primarily used to
relieve moderate to severe pain.
It is used pre operatively, its effect is
on reducing patients anxiety and in
assisting in induction of anesthesia.
It is the drug of choice for clients with
pain from MI, Pulmonary edema and
dyspnea from acute left ventricular
failure.

12. PHARMACOKINETICS
Absorption
• It depends on the route of administration,
• Morphine ingested orally is generally
absorbed in one and half to two hours.
• It reaches liver for metabolism before
reaching systemic circulation.
• Absorption after IM or SC injection
occurs in 30 to 60 minutes.

13. PHARMACOKINETICS
Distribution
• It occurs quickly.,
• After administration morphine leaves the
blood and directly enters the kidney, lungs,
liver and spleen.
• Its action on skeletal muscle is limited,
since the drug is not very lipid soluble, it
does not cross the BBB easily
• .

14. DURATION OF ACTION
METHOD OF ADMINISTRATION ONSET OF ACTION
Oral 4 to 12 hours
IM or SC 10 to 30 minutes
IV 15 to 30 minutes

15. PHARMACOKINETICS
BIOTRANSFORMATION
• It occurs in the liver.
• Excretion occurs in the kidney.
• Only traces of morphine is
founded in body after 48 hours.
.

16. PHARMACODYNAMICS
Morphine produces analgesia by
binding preferentially to the mu
and delta receptors.
Morphine targets the areas
involved with regulation of pain
perception, respiration and
affective behaviors.

17. THERAPEUTIC USES
Analgesia
Suppression of cough and dyspnea.
Sedation
In the treatment of diarrhea
As preanesthetic medication
In the treatment of the left ventricular
failure.

18. CONTRAINDICATIONS
Head Injury, because morphine can cause
increased intracranial tension, which can
leads to marked respirator depression.
Myxedema
Bronchial asthma – Morphine releases
histamine which can trigger
bronchoconstriction.
Elderly patients
In hypotensive states.

19. ADVERSE REACTIONS
CNS Side effects
Confusion, anxiety, lethargy, nausea and
vomiting.
GIT Side effects
Constipation
Other Side effects
Urinary retention, dry mouth, dysphoria,
hypotension, skin rash, itching and
urticaria.

20. MORPHINE POISONING
Acute poisoning with morphine and other
opioids occurs with overdoses.
Signs and Symptoms
Coma, Pinpoint pupils, and respiratory
depression which frequently called triad.
TREATMENT
Administration of antagonist Naloxone.
Support of Respiratory and Cardio Vascular
function.