ANALGESICS
Analgesics
• Analgesics are drugs that relieve pains
• They are capable of producing analgesia
• Pain is subjective
• Description of intensity of pain
Mild
Moderate
Severe
Types of pain
Acute pain
Chronic pain
Nociceptive pain
Neuropathic pain
Psychogenic pain
Physiology of pain
1. Transduction
 Mechanical, chemical or thermal stimulus is
converted into a biological signal
 Inflammation causes nearby immune cells to release
neurotransmitters such as serotonin, histamine,
prostaglandins, bradykinin, and substance P that
can trigger pain
 Nociceptors are activated to generate action
potential
2. Transmission
Action potential are transmitted from
the site of injury to spinal cord and
cerebral cortex of the brain for
processing
3. Perception
cerebral cortex processes the
experience of pain and its
characteristics such as location,
intensity, and what makes the pain
better or worse
• Modulation
descending neurons travel from
brainstem and release neuromodulators
such as endorphins and enkephalins
which inhibit the transmission of pain
signals and produce analgesic (painrelieving) effects
Classification of analgesics
1. Opioids
2. Non-opioids
3. Adjuvants
OPIOIDS
• They work by binding to specific
receptors in the central nervous system
• e.g. morphine, codeine, oxycodone,
hydrocodone, hydromorphone,
oxymorphone, pethidine, tramadol and
fentanyl
Morphine
Indications
• Moderate to severe pain such as:
Pain from surgery, trauma
Advanced illnesses such as cancer
Myocardial infarction
Dyspnea (shortness of breath)
Morphine
Mechanism of action
• Morphine binds to opioid receptors in the CNS
• Alters the perception of pain by inhibiting the
transmission of pain signals
• Alters the response to painful stimuli by activation
of receptors leading to feelings of euphoria,
relaxation, and an altered sense of well-being
Morphine
Contraindications
• Hypersensitivity or allergy to morphine
• Respiratory depression
• Paralytic ileus
• Head injury or Increased Intracranial Pressure
• Acute alcohol intoxication or drug abuse
• Use of Monoamine Oxidase Inhibitors (MAOIs)
Morphine
Side effects
 Respiratory depression
 Confusion
 Hypotension
 Dizziness
 Sedation
 Constipation
 Nausea and vomiting
 Acute urinary retention
 Elevation of intracranial pressure, particularly in head injury
Morphine
Drug interactions
• CNS depressants (e.g., barbiturates, benzodiazepines,
alcohol)
• Anticholinergic drugs (e.g., antihistamines, tricyclic
antidepressants, atropine-like drugs) can exacerbate
morphine-induced constipation and urinary retention
• Antihypertensive drugs can exacerbate morphine
induced hypotension
• Naloxone (narcan) suppress the symptoms of opioid
overdose
Morphine
Nursing considerations
1. Use supportive nursing measures as relaxation
techniques to relieve pain before using narcotics
2. Explore the source of pain, use non-narcotic
analgesia if possible
3. Administer the medication when needed
4. Monitor mental status
5. Monitor Respiratory rate (drug may lead to
respiratory depression)
6. Monitor blood pressure (hypotension may occur)
7. Monitor pulse rate (if 60/m withhold the drug)
8. Watch for constricted pupils. Document it and
notify the physician
9. Monitor bowel function, since drug may cause
constipation
10.Encourage client to empty bladder every 3-4 hrs
(since drug may cause urinary retention)
11.Inform the client/family that the drug may become
habit forming and leading to addiction
12.Document any history of asthma or other
contraindications
13.Have emergency equipment and narcotic antagonist
available
14.Naloxone is used to reverse opioid such as morphine
overdose
Pethidine (Meperidine)
• Pethidine is a synthetic opioid
analgesic medication used primarily
for the relief of moderate to severe
pain. It shares most pharmacological
properties with morphine
NON-OPIOIDS
• Mechanisms:
Reducing inflammation
Blocking pain signals
Altering pain perception
NON-OPIOIDS
• Types of non-opioid analgesics:
Acetaminophen (paracetamol)
Non-steroidal Anti-Inflammatory
Drugs (NSAIDs). E.g. ibuprofen
and diclofenac
Salicylates e.g. aspirin
Paracetamol (Acetaminophen)
Mechanism of action:
• Works in the CNS to inhibit the synthesis of
prostaglandins
Paracetamol (Acetaminophen)
Indications:
 Mild to moderate pains
 Fever
 Headache
 Toothache
 Osteoarthritis
 Colds and flu symptoms
 Sore throat
Paracetamol (Acetaminophen)
Side effects / adverse effects
Rashes
Blood disorders (e.g. thrombocytopenia,
leucopenia, neutropenia)
Hypotension
Flushing
Tachycardia also reported on infusion
Liver damage
Nursing considerations for paracetamol
1. Inform patients about the risk of liver injury
2. Assess pain prior to and after administration
3. Administer with a full glass of water
4. Advise patients to consume no more than
4000 mg of acetaminophen a day
Nursing considerations for paracetamol
5. Advise patients not to drink alcohol
while taking acetaminophen
6. Reduce dose of chronic alcoholics to
take not more than 2000 mg of
acetaminophen a day
Nursing considerations for paracetamol
7. Advise patients with liver disease to ask their
prescribers whether acetaminophen is safe
8. Monitor liver function tests, especially in patients
with preexisting liver disease or those taking other
medications that may affect liver function.
9. Educate the patient about the signs of liver toxicity,
such as jaundice, dark urine, pale stools, and
abdominal pain
Salicylates
• They are a class of compounds that
contain the chemical salicylic acid
• Aspirin (Acetylsalicylic acid) is one of
the most well-known and widely
used salicylate
Aspirin
Mechanism of action
• inhibits the activity of an enzyme; cyclooxygenase (COX)
• COX is of two types; COX-1 and COX-2
• Cox produces prostaglandin (mediators in the process of
inflammation) and thromboxane (for blood clotting and
constriction of blood vessels)
• Aspirin therefore reduces the production of
prostaglandins and thromboxane
Aspirin
Indications
• Headache
• Toothache
• Neuralgias
• Rheumatoid arthritis
• Fever
• To prevent coronary thrombosis and stroke in
those at risk
Aspirin
Contraindications
• Hypersensitivity or allergy
• Peptic Ulcer Disease
• Bleeding disorders such as hemophilia
• Asthma
• Pregnancy
• Children under the age of 16 years (NB: because of
Reye’s Syndrome)
Aspirin
Side effects / adverse effects
• Gastrointestinal upset such as heartburn, indigestion,
and stomach pain
• Gastrointestinal bleeding
• Bruising and easy bleeding
• Allergic reactions such as skin rash, hives, swelling,
difficulty breathing, or anaphylaxis
• Asthma exacerbation
• Tinnitus (ringing in the ears)
Aspirin
Nursing considerations
1. Take drug with or after food or with milk to
decrease GI irritation
2. Assess for history of asthma and history of
hypersensitivity
3. Do not use with other anticoagulants
4. Note any history of peptic ulcer
5. Report signs of side effect e.g. gastric irritation if
occurs
Aspirin
Nursing considerations
6. Monitor the patient for signs of gastrointestinal bleeding
7. Assess for any signs of allergic reactions, such as rash,
hives, swelling, or difficulty breathing
8. Aspirin is not given 1 week before & after surgery to
prevent bleeding
9. Teaches patient about the toxic symptoms (ringing in the
ears, dizziness, mental confusion) and ask him/her to
report it to physician
NON-STEROIDAL ANTI-INFLAMMATORY DRUGS
(NSAIDs)
Aspirin
Diclofenac
Ibuprofen
Naproxen
Celecoxib
Mefenamic acid
Piroxicam
Meloxicam
Indomethacin
Diflunisal
Etodolac
Fenamates
Meclofenamate
sodium
Fenoprofen
Ketoprofen
Methylsalicylate
Nabumetone
Oxaprazin
Sulindac
Tolmetin
NSAIDs
Indications
• Mild to moderate pain, such as
headache, dental pain, menstrual
cramps, and musculoskeletal pain
• Inflammation associated with conditions
like arthritis, tendinitis
• Fever
NSAIDs
Contraindications
• Allergy or hypersensitivity
• Peptic ulcer disease
• History of gastrointestinal bleeding
• Bleeding disorders like hemophilia
• Severe kidney disease
• Severe Liver Disease
NSAIDs
Side effects / adverse effects
• Epigastric distress
• Nausea
• Vomiting
• Gastrointestinal bleeding
• Prolonged bleeding time
• Respiratory depression
• Tinnitus (ringing in the ears)
• Hypersensitivity reactions such as urticaria,
bronchoconstriction
NSAIDs
Nursing consideration
1. Perform a thorough assessment of the patient's
medical history
2. Evaluate the patient's pain and inflammation
levels
3. Monitor vital signs
4. Assess for gastrointestinal symptoms
NSAIDs
Nursing consideration
5. Educate the patient about the proper use of NSAIDs
6. Instruct the patient to take NSAIDs with food, milk, or a
full glass of water to reduce the risk of gastrointestinal
irritation
7. Advise patients to avoid alcohol while taking NSAIDs, as it
can increase the risk of gastrointestinal bleeding
8. Discuss the importance of promptly reporting any adverse
effects or changes in symptoms to the healthcare provider
NSAIDs
Nursing consideration
9. Monitor the patient's compliance with the
medication regimen
10.Monitor for potential interactions with other
medications the patient is taking
11.Monitoring liver and kidney function in patients
on long-term NSAID therapy or those at risk of
organ dysfunction