In the Health Light blog, we will learn about Definition, Classification, Pharmacologic Actions, Therapeutic uses, Precautions with Morphine Therapy and Untoward Effects of Morphine . All you have to do, dear reader, is to follow to the end
Definition of Opioid
The term opiate refers to drugs derived from opium . Opium is the milky exudate obtained by incising the unripe seed capsules of the poppy plant , Papaver Somniferum . On drying in air , the exudate forms a gummy brownish mass . This is further dried and powdered to make the powdered opium which contains morphine, codeine , thebaine papaverine and noscapine . The predominant pharmacological characteristics of opium are due to morphine which constitutes about 10 % of its weight. The term opioid refers to all drugs that have opium or morphine-like properties .Classification of Opioid
1_ Morphine and related opioids : Morphine , Codeine , Heroin , Levorphanol
2_ Meperidine and congeners : Meperidine , Fentanyl , Diphenoxylate , Loperamide
3 _ Methadone and congeners : Methadone , Propoxyphene .
4_ Mixed Agonist Antagonists and Partial Agonists : Pentazocine , Butorphanol , Nalbuphine , Buprenorphine
5 _ Opioid antagonists : Naloxone , Naltrexone
Pharmacologic Actions of opioid (Morphine)
The actions of morphine on CNS ( Central Nervous System )a _ Analgesia : selectively relieves both visceral and somatic pain ; dull continuous pain is relieved more effectively than sharp intermittent one
b _ Euphoria , Mental Clouding and hypnosis : With therapeutic doses morphine produces a false sense of emotional shell being termed euphoria . Euphoria eliminates the normal fear and tension and aids the analgesic
c _ Pupil :
Morphine causes constriction of the pupil (miosis) due to stimulation of the oculomotor nucleu
d _ Respiration : Therapeutic doses of morphine in man depress all phases of respiratory activity
e _ Cough :
The cough center is more sensitive to morphine than the respiratory center.
f _ Nausea and Vomiting :
Morphine depresses the cough center Morphine produces nausea (40%) and vomiting (15%)
Also the morphine actions on the Gastrointestinal tract and Cardiovascular system
Therapeutic uses of Morphine
1 _ Relief of Pain :
The main therapeutic use of morphine is to relieve severe pain as that encountered in acute myocardial infarction , acute pericarditis , bone fractures , burns , pulmonary embolism , pleural effusion , spontaneous pneumothorax and terminal stage of malignancy.
2 _ Cardiac Asthma with Pulmonary Edema :
Morphine is valuable in the treatment of acute left ventricular failure . The dyspnea is dramatically relieved in response to intravenous morphine
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3 _ In Preanesthetic Medication and as supplement :
during general anesthesia with inhalational or I.V. agents. In high doses opioids are used as primary anesthetic agents
4 _ Antitussive :
Morphine is useful in dry non productive cough only in cases that have failed to respond to the non narcotic non addictive antitussives .
5 _ To Check Diarrhea :
Opium preparations ( opium tincture , 0.5-1 ml ; paregoric , 4 ml ) are sometimes used for relief of diarrhea
Precautions with Morphine Therapy
1 _ The use of morphine in asthmatic patients is hazardous as it depresses the respiratory centre and cough reflex , releases histamine and tends to dry secretions .
2 _ When morphine is administered to the mother during labor, it crosses the placental barrier and the newborn infant may exhibit manifestations of respiratory depression " asphyxia neonatorum "
3 _ Old people and infants are more susceptible to the respiratory depressant effect of morphine .
4 _ In acute abdomen, pain is a chief diagnostic symptom and its total abolition may interfere with the diagnosis . Morphine should not be given until the diagnosis is made.
5 _ Patients with myxedema are more sensitive to morphine while hyperthyroid individuals seem more tolerant . An ordinary dose of morphine given to myxedematous patients may cause coma for about 3 days .
6 _ Patients with reduced blood volume are more susceptible to the hypotensive effect of morphine and therefore should be used with caution in any type of hemorrhage .
Untoward Effects to the Use of Morphine
The important untoward effects are :
1 _ Physical Dependence (Addiction) Morphine addiction mainly results from its euphoriant effect . When given I.V. it produces a warm flushing of the skin and sensations in the lower abdomen described by addicts as similar in intensity and quality to sexual orgasm and known as a " rush , " kick " or " thrill ". Morphine addicts are usually , but not always , malnourished and debilitated . Even though they are capable of performing complex motor and intellectual tasks , the productivity and the utility of the individual to the society usually suffers . Due to depression of sexual desire, marital conflicts are common. Economic distress may often lead to suicidal tendency .
2 _ The Abstinence Syndrome :
The signs and symptoms of Abstinence Syndrome can be organized as follows :
a _ Autonomic hyperactivity as lacrimation , rhinorrhea , sweating , dilated pupils , increased blood pressure and heart rate, hyperpyrexia, vomiting , abdominal pain and diarrhea .
b _ Behavioral hyperexcitability as anxiety , restlessness , yawning , tremors and insomnia.
c _ Muscle and joint pains: most of the gross signs and symptoms of abstinence syndrome disappear in 7-10 days but the patient may complain of restlessness, insomnia, weakness , back and leg pains for several weeks .
3 _ The Abstinence Syndrome results not only from drug withdrawal but also when it is displaced from its site of action by an antagonist such as naloxone . The intensity of naloxone
precipitated withdrawal is usually nature severe than that seen after abrupt withdrawal of the drug . It develops within few minutes , reaches its peak intensity within 1/2 an hour and continues until the antagonist is eliminated
Thus, we have finished reviewing the most important points about Definition, Classification, Pharmacologic Actions, Therapeutic uses, Precautions with Morphine Therapy and Untoward Effects of Morphine . Don't forget to share the topic on social media
resources and references
The Dentist’s Drug and Prescription GuideMea Weinberg and Stuart J. Froum
Stuart L. Segelnick, Consulting Editor
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