Pharmacotherapy of Osteoathritis

Question 1

Pharmacotherapy of Osteoarthritis

Answer 1

• Reduction of Pain and Inflammation

1. Nonopioid Analgesics (For Pain Relief)
   - Acetaminophen
   - Tramadol
2. Nonsteroidal Anti-Inflammatory Drugs (NSAIDs) (For relied of both Pain and Inflammation)
   - Salicylates (Aspirin)
   - Ibuprofen
   - COX-2 Inhibitors (Celebrex)
3. Topical creams, gels, sprays, patches, or ointments containing Salicylates or NSAIDs
4. Intra-articular Injection of Corticosteroids in Acute Phase
5. Sodium Hyaluronate Injections into Joint
6. Herbal Products

Question 2

Acetaminophen

Answer 2

• Centrally acting nonopioid analgesic
• *Inhibits synthesis of prostaglandins, which acts as mediators of Pain and Fever, primarily in the Central Nervous System
• *Initial treatment choice of OA
• Opioids such as Codeine may be combined with Acetaminophen for Severe Pain

Question 3

Tramadol

Answer 3

• Centrally acting Analgesic
• For treatment of Moderate to Severe Pain
• *MOA: Inhibit the reuptake of Norepinephrine and Serotonin in Spinal Neurons

Question 4

Properties of NSAIDs (AAAA)

Answer 4

• Analgesic
• Anti-inflammatory
• Antipyretic
• Anti-platelet Inhabitation (Aspirin)

Question 5

MOA of NSAIDs

Answer 5

1. Inhibition of the synthesis of Prostaglandins (Lipids found in the Tissue)
   - They block inflammation by inhibiting cyclooxygenase, the key enzyme in the biosynthesis of prostaglandins
2. COX-1 & COX-2
   - 1: Present in all tissues, and synthesises prostaglandins which have protective functions such as decrease gastric acid secretion, and increase renal blood flow, regulating smooth muscle tone in blood vessels and bronchial tree
   - 2: Formed only after tissue injury and promotes inflammation
3. Nonselective NSAIDs block both COX-1 and COX-2
   - Decreases inflammation
   - Undesirable effects: Bleeding, GI Irritation, Decrease renal function

Question 6

Adverse Effects of NSAIDs

Answer 6

1. Gastrointestinal
   - Dyspepsia, Heartburn, Epigastric Distress, Nausea
   - GI Bleeding
   - Mucosal Lesions (Erosions/Lacerations)
2. Renal
   - Reductions in Creatinine Clearance
   - Acute Tubular necrosis with Renal failure
3. Cardiovascular
   - Noncardiogenic pulmonary oedema

Question 7

Drug Interactions with NSAIDs

Answer 7

• Serious interactions can occur when given with:
  1. Anticoagulants
  2. Aspirin
  3. Corticosteroids and other Ulcerogenic Drugs
  4. Diuretics and ICE Inhibitors

Question 8

Nursing Implications of NSAIDs

Answer 8

1. Assessment
   - For contraindications: GI Lesions, Pepticular Disease, Bleeding Disorders
2. Perform
   - Laboratory studies as indicated (Cardiac, Renal, Liver Function studies, CBC; Platelet Count)
   - Medication history to assess for potential drug interactions
3. Education
   - Various adverse effects of NSAIDs (To inform/notify prescriber if effects become severe or if bleeding or if GI Pains occur)
4. Monitor
   - For therapeutic effects, which vary according to the condition being treated (e.g. Decrease in swelling, Pain, Stiffness, and Tenderness of a Joint or Muscle area)

Question 9

Chemical Categories of NSAIDs

Answer 9

1. Salicylates
   - No longer recommended, because high doses needed to relieve pain for OA
   - Can cause GI Bleeding
2. Acetic Acid Derivatives
3. Enolic Acid Derivatives
4. Propionic Acid Derivatives
5. Cyclooxygenase-2 (COX-2) Inhibitors
   - Celecoxib (Celebrex)
   - First and ONLY remaining COX-2 Inhibitor
   - *Indicated for OA, Rheumatoid Arthritis, Acute Pain symptoms, Ankylosing Spondylitis, Primary Dysmenorrhea
   - *Adverse Effects: Headache, Sinus Irritation, Dizziness, Diarrhoea, Hypertension, Fatigue, Lower Extremity Oedema
   - *Contraindicated for patients with Sulfa Allergy

Question 10

MOA of Ibuprofen

Answer 10

Inhibit prostaglandin synthesis

Question 11

Administration Alert for Ibuprofen

Answer 11

1. Give drug on empty stomach (If nausea, vomiting or abdominal pain occurs, give with food)
2. Be aware of patients with Asthma and allergies to Aspirin
3. Pregnancy category C -> Changes to D after 30 weeks gestation

Question 12

Adverse Effects of Ibuprofen

Answer 12

1. Nausea, Heartbun, Epigastric Pain, Dizziness
2. GI Ulcerations with occult or gross bleeding (Especially if taken in high doses for prolonged periods)
3. May lead to renal impairment (Chronic Usage)

Question 13

Contraindications of Ibuprofen

Answer 13

• For patients with:
  1. Active Peptic Ulcers
  2. Significant Renal/Hepatic Impairments
  3. Syndrome of Nasal Polyps, Angioedema, Bronchospasm
  4. HF, Serious HTN, or History of Stroke or MI

Question 14

Interactions with Ibuprofen

Answer 14

1. Drug-Drug
   - Avoid when taking Anticoagulants/Coagulants modifiers as it affects platelet function
   - Aspirin can decrease the anti-inflammatory action of Ibuprofen
   - Antihypertensive action of Diuretics, BBs, ACE Inhibitors can be reduced
   - Use with other NSAIDs, Alcohol, Corticosteroids may cause serious adverse effects
2. Herbal/Food
   - Feverfew, Garlic, Ginger or Ginkgo may increase risk of Bleeding

Question 15

Sodium Hyaloronate

Answer 15

• Option for patient with moderate OA / Do not respond adequately with Analgesics
• Natural chemical found in Synovial Fluid
• Injection to Knee Joint, 1 Injection per week for 3-5 weeks
• Replaces / Supplements the body’s natural hyaluronic acid
• Provides a barrier what prevents friction and further inflammation

Question 16

Herbal Products (Glucosamine & Chondroitin)

Answer 16

1. Used to treat pain of OA
2. Adverse Effects
   - GI Discomfort
   - Drowsiness, Headache, Skin reactions (Glucosamine)
3. Drug Interactions
   - Enhances effects of Warfarin
   - May increase Insulin resistance (Glucosamine)