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lec 7b Use of Opioids in Pain Management.pptx
1. THE USE OF OPIOIDS IN PAIN MANAGEMENT
Dr. Antony L. Yiaile
Consultant Pharmacist and Lecturer of Clinical
Pharmacology & Toxicology
Department of Clinical Medicine University of
Kabianga
Kericho County Kenya
2. Introduction
Pain is one of the oldest medical challenges facing humankind.
It has long history in medicine, religion, and social science.
Unfortunately, there is lack of detailed information on contemporary,
patient-centered approach to understand and manage acute and
chronic pain.
This knowledge gap in pain management is leading to ineffective and
counterproductive pain management strategies (Sabatowski et al
2004).
Therefore, there is the need for better our understanding on
contemporary, patient-centered approaches on pain management.
3. Use of Opioids in Pain Management
Opioid use in pain management dates back to the 1800s.
The use of opioids increased because of the need to treat
serious injuries sustained in warfare.
Advancements in pain physiology, the discovery of endogenous
endorphins and opioid receptors, and the development of
synthetic opioids greatly influenced its use.
By nature, it is extracted from opium poppy plant and functions in
the brain to relief pain and bring about relaxation.
What are we using in the healthcare?
The natural forms such as Morphine Codeine
Semi-synthetic forms such as Oxycodone and Meperidine
Fully synthetic forms such as Fentanyl and Methadone
4. Medical vs Non-medical opioid users
Medical users Non-medical users
They take opioids for the
prescribed use (for pain relief)
with no extra doses for pain
relief or pleasurable effect
It is illicit,
Taken in manner other than
the one prescribed by a
physician.
Given by or stolen from family
or friends, Doctor shopping,
bought from drug dealers
Concern: risk of dependence goes up
with amount and length of treatment
5. How Opioids Work to Manage Pain
First, they attach themselves to and activate opioid receptors on
nerve cells in the brain, spinal cord, gut and other parts of the
body especially those that feel pain and pleasure.
When this happens, they block pain messages sent from the
body through the spinal cord to the brain thus managing pain.
Although they can effectively relieve pain, they carry some risks
and can be highly addictive.
The risk of addiction present when they are used in the
management of chronic pain over a long period of time.
6. tTerminologies used in opioid therapy
Opioids: Drugs that bind to opioid receptors which are found principally in the central nervous system and the gastrointestinal
tract
Narcotic:This is a term derived from the Greek word “stupor” and it originally referred to any drug that induced sleep but is
now associated with opioids.
Tolerance: refers to a decrease in effectiveness of a drug with its repeated administration and an increased dose is required to
produce the same physiological response.
Dependence: refers to a complex set of changes in the homeostasis of an organism that causes a disturbance of the homeostatic
set point of the organism if the drug is stopped.
Withdrawal: is the unpleasant, sometimes life-threatening physiological changes that occur due to the discontinuation of use of
some drugs after prolonged regular use. In the case of opioids signs of withdrawal include chills, fever, sweating, yawning,
vomiting, diarrhea, nausea, dizziness and hypertension.
Addiction/Substance abuse: refers to dependence on a habit forming substance or behavior that the person is powerless
to stop. There are two types of addictions:
Substance addictions e.g. alcoholism, drug abuse, smoking.
Process addiction e.g. gambling, spending,shopping, eating e.t.c
7. Opioid Receptors and Neurological Responses
Individual opioid receptors have unique neurological feedback.
Each opioid has a different binding affinity for the different types of opioid
receptors.
Three classical types of opioid receptors include
(a) μ (Mu),
(b) κ (Kappa)
(c) δ (delta).
μ (Mu) Opioid Receptors
They are found in the thalamus and brainstem.
Its three subtypes include μ1, μ2 and μ3 receptors
Activation of subtypes brings about pain alleviation, euphoria , sedation and
respiratory depression
8. Cont..
The Kappa Opioid Receptors
They are found in the spinal cord, brainstem and the limbic system.
As this receptor is activated, it induces pain relief, sedation, shortness
of breath, and dependency.
The delta Opioid Receptors
They are distributed in the spinal cord, digestive tract and the brain.
This receptor's stimulation has analgesic and antidepressant benefits,
but it may also induce respiratory distress.
9. PHARMACOLOGICAL EFFECTS OF OPIODS
i. Analgesia
ii. Medullary Effects
iii. Hypothalamic Effects
iv. Neuroendocrine Effects
v. Convulsions
i. GI Effects
ii. Effects on the Skin
iii. Immune Function and Histamine
iv. Cardiovascular Effects
v. Antitussive Effects
vi. Tolerance and Physical Dependence
10. Opioid Analgesics
Classification Example FDA-approved indications
MIXED OPIOID AGONIST–
ANTAGONISTS OR PARTIAL
AGONISTS
OPIOID ANTAGONISTS
Pentazocine
Butorphanol
Nalbuphine
Buprenorphine
Naloxone
Naltrexone
Nalmefene
Relied of moderate to severe
pain
Pure antagonists
MORPHINE AND RELATED
OPIOID AGONISTS
MORPHINE
CODEINE AND OTHER
PHENANTHRENE
DERIVATIVES
MEPERIDINE AND RELATED
PHENYLPIPERIDINE
DERIVATIVES
Relief of moderate to severe
acute pain
Relief of moderate to
moderately severe chronic
pain in patients requiring
11. Considerations for opioid use
There are many opioids and opioid combination products each with its own
treatment uses.
Therefore it’s crucial to use the right opioid and use it correctly.
Factors to consider before choosing the best opioid product(s) for an individual
treatment include;-
Age
This is because not all opioid products are appropriate for all age groups.
Severity of the pain
Some opioids medications are stronger than others. For example, codeine-
acetaminophen, are only used for mild to moderate pain.
Pain treatment history,
Some opioids such as fentanyl and methadone are only appropriate for those
already taking the drug and in need of long-term therapy.
12. Cont..
Other conditions that you may have
Kidneys are involved in removal of some opioid medications from body,
therefore, poorly functioning kidney may expose one to the side effects
of some opioids such as codeine, morphine etc
Other drugs you take
Some drugs may interact antagonistically with certain opioids
History of substance use disorders
Some opioids such as Embeda and Targiniq ER are designed to
reduce the risk of misuse.
13. Opioid complications and side effects
Healthcare professional need to manage pain medications so closely
because of some complications and side effects.
Abuse and diversion of opioids is becoming a challenge as their
availability increases chances of miususe (Ricardo Buenaventura et al
2008)
Opioids have been found to decrease total sleep time and sleep
efficiency (Kurz & Sessler, 2003).
The risk of opioid-induced bladder dysfunction (i.e., difficulty voiding or
frank urinary retention) (Ricardo Buenaventura et al 2008).
Opioid-induced cardiac adverse events such as hypotension (Ricardo
Buenaventura et al 2008).
15. Opioid Receptor Effect
mu opioid receptor Decreases NK cell activity (central)
Macrophage phagocytosis (central)
Inhibits T-cell proliferation (central)
Nitric oxide release (peripheral)
delta opioid receptor Increases NK cell activity (central)
Potentiates humoral immune response
(MOR dependent)
Decreases PFC response
kappa opioid receptor Pronounced suppression of humoral
immunity
N.K=natural killer
PFC=plaque forming cells
Central immunologic effects of opioids
16. Opioid-induced Constipation
Constipation is a common effect to 40% to 95% of patients treated with
opioids even with a single dose of morphine (Swegle and Logemann,
2006).
Although constipation may be seen as a minor effect, long-term
consequences can lead to high morbidity and mortality (Ricardo
Buenaventura et al 2008).
There is a need for effective treatment of opiate-induced constipation
Medical agent Formula/strength Adult dosage Side effect/complication
Polycarbophil(Fibercon) Tablets: 625 mg 2 tabs 1 to 4
times daily
Increased intestinal gas.
Lactulose Liquid: 10 g per 15 mL 15 to 60 mL daily Flatulence, diarrhea, nausea
or vomiting.
Tegaserod (Zelnorm) Tablets: 2 mg, 6 mg 2 times daily headache, abdominal pain,
and diarrhea
17. Strategies to Prevent Opioid Use Disorder
Establishment of prescription drug monitoring programs
Sensitization on the risks of prescription opioids and the cost of
overdose on patients.
Educating patients on the safe storage and disposal of prescription
opioid.
Educating providers on opioid prescribing guidelines
Quality improvement programs to increase implementation of
recommended prescribing practices
Enactment of drug prescription laws
19. References
Sabatowski, R., Schafer, D., Kasper, S. M., Brunsch, H., & Radbruch, L.
(2004). Pain treatment: a historical overview. Current pharmaceutical design,
10(7), 701-716.
Ricardo Buenaventura, M., Rajive Adlaka, M., & Nalini Sehgal, M. (2008).
Opioid complications and side effects. Pain physician, 11, S105-S120.
Kurz, A., & Sessler, D. I. (2003). Opioid-induced bowel dysfunction. Drugs,
63(7), 649-671.
Swegle, J. M., & Logemann, C. D. (2006). Management of common opioid-
induced adverse effects. American family physician, 74(8), 1347-1354.
