INTRODUCTIONAnalgesics are medications used torelieve pain without reducing theconsciousness of the patient.They work by reducing the amount ofpain felt and this is generally achievedby interfering with the way the painmessage is transmitted by the nerves.Analgesics will not treat the cause ofthe pain but they will provide temporaryrelief from pain symptoms.
OPIOID ANALGESICSThe opioid analgesics which areprescription only medicines that are verypotent, being chemically related tomorphine.Opioid analgesics are prescribed formoderate to severe pain, particularly ofvisceral origin, and are used in step twoand step three of the analgesic ladder.
Dependence and tolerance are wellknown features with regular usealthough this should not inhibitprescribing in palliative care.Some chronic non-malignantconditions benefit from analgesiccontrol with opioids, but patientsshould be reviewed regularly.
OPIUM, the greek name for poppy juice. Isobtained from the juice of the papaversomniferum.
ACTIONS OF OPIOID ANALGESICSOpioid analgesics interacts with fourmajor receptors in the CNSMu receptorsKappa receptorsSigma receptors andDelta receptors
MORPHINEMorphine is the most important alkaloidof of opium.Morphine produces analgesia throughactions in the brain and spinal cord.Morphine is readily absorbed from theGI tract and subcutaneous and muscletissue.Morphine is administeredintravenously, epidurally, andintrathecally.
PHARMACOTHERAPEUTICSMorphine sulfate is primarily used torelieve moderate to severe pain.It is used pre operatively, its effect ison reducing patients anxiety and inassisting in induction of anesthesia.It is the drug of choice for clients withpain from MI, Pulmonary edema anddyspnea from acute left ventricularfailure.
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.
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• .
DURATION OF ACTIONMETHOD OF ADMINISTRATION ONSET OF ACTION Oral 4 to 12 hours IM or SC 10 to 30 minutes IV 15 to 30 minutes
PHARMACOKINETICS BIOTRANSFORMATION• It occurs in the liver.• Excretion occurs in the kidney.• Only traces of morphine is founded in body after 48 hours. .
PHARMACODYNAMICSMorphine produces analgesia bybinding preferentially to the muand delta receptors.Morphine targets the areasinvolved with regulation of painperception, respiration andaffective behaviors.
THERAPEUTIC USESAnalgesiaSuppression of cough and dyspnea.SedationIn the treatment of diarrheaAs preanesthetic medicationIn the treatment of the left ventricularfailure.
CONTRAINDICATIONSHead Injury, because morphine can causeincreased intracranial tension, which canleads to marked respirator depression.MyxedemaBronchial asthma – Morphine releaseshistamine which can triggerbronchoconstriction.Elderly patientsIn hypotensive states.
ADVERSE REACTIONS CNS Side effectsConfusion, anxiety, lethargy, nausea and vomiting. GIT Side effectsConstipation Other Side effectsUrinary retention, dry mouth, dysphoria, hypotension, skin rash, itching and urticaria.
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. TREATMENTAdministration of antagonist Naloxone.Support of Respiratory and Cardio Vascular function.