OA, Gout, Osteoporosis Flashcards
Osteoarthritis Defined
Progressive disease can result in chronic pain, restricted ROM, and muscle weakness, especially if a weight-bearing joint such as knees, hips, cervical or lumbar spine, distal interphalangeal (DIP) joints, and carpometacarpal joint (base of the thumb) is affected.
Osteoarthritis Forms Defined
Primary or Idiopathic: Arises from physiologic changes that occur with normal aging
Secondary: results from traumatic injuries or inherited conditions and may present as hemochromatosis, chondrodystrophy, or inflammatory OA.
Osteoarthritis Pathophysiology
OA must be differentiated from other forms of arthritis because the physiologic changes specific to the condition dictate disease management.
Although most forms of arthritis, including OA, result in degeneration of articular cartilage, the subsequent formation of new bone is a change specific to OA.
Osteoarthritis Diagnostic Criteria: Hand
Pain, aching, or stiffness and three of the following:
Hard tissue enlargement of >2 joints; Hard tissue enlargement of >2 DIP joints; <3 swollen metacarpophalangeal joints; deformity of >1 selected joint
Osteoarthritis Diagnostic Criteria: Hip
Pain and two of the following:
Erythrocyte sedimentation rate (ESR) <20 mm/h; Radiographic femoral or acetabular osteophytes; Radiographic joint space narrowing
Osteoarthritis Diagnostic Criteria: Knee
Knee pain and three of the following:
>50-year-old; stiffness <30 minutes; crepitus; bony tenderness, Bony enlargement; no palpable warmth
OA Diagnostic Criteria: Clinical and Radiographic Diagnosis
Knee pain and osteophytes and one of the following:
>50-year-old; stiffness <30 minutes; crepitus
OA Diagnostic Criteria: Clinical and Laboratory diagnosis
Knee pain and 5 of the following:
Age >50 years; stiffness <30 minutes; crepitus; bony tenderness; bony enlargement; no palpable warmth; ESR <40 mm/h; RF <1:40; synovial fluid signs of OA (clear, viscous, or WBC count <2,000/mm3)
OA Topical NSAID’s Indications
Topical therapy is preferred over systemic therapy by the European League Against Rheumatism (EULAR) and the Osteoarthritis Research Society International (OARSI).
Topical nonsteroidal antiinflammatory drugs (NSAIDs) are strongly recommended by the American College of Rheumatology (ACR) for knee osteoarthritis and conditionally for hand osteoarthritis. Due to concerns with absorption in hip osteoarthritis, topical therapy is typically not recommended.
Systemic therapy may be more effective depending on the number and location of joints affected. Topical therapy is an attractive option due to the relatively benign side effect profiles.
OA NSAID Indications
2nd line therapy = oral NSAIDs
NSAIDs further classified according to their chemical structure, all exhibit cyclooxygenase (COX) inhibition.
A practitioner is prescribing a medication for a patient recently diagnosed with OA. What is the recommended first line of treatment for OA?
Acetaminophen. First-line pharmacotherapy for OA is geared toward analgesia, specifically with acetaminophen (Tylenol). Due to acetaminophen’s cost effectiveness and safety, it is currently the first-line treatment recommended in guidelines by the ACR, the EULAR, and others.
Diclofenac (Voltaren) MOA
The mechanism of action for topical diclofenac is the same as for oral
NSAIDs. The benefit is that minimal diclofenac is absorbed when applied topically, which then
decreases the risk of adverse events. Data have shown that only 6% to 10% of the topical gel and
2% to 3% of the solution is absorbed.
Diclofenac (Voltaren) Dosage
LE’s: 4 g should be applied four times a day; if used on the UE’s: 2 g should be applied four times a day. The entire total daily dose should not exceed
32 g/d.
Diclofenac (Voltaren) Contraindications
Topical diclofenac carries the same warnings and contraindications as oral
NSAIDs, although the risk is less. Also, topical diclofenac is contraindicated on non-intact or
damaged skin.
Diclofenac (Voltaren) Adverse Events
pruritus, rash, dry skin, pain, and exfoliation.
Capsaicin MOA
Depletes substance P.
Initially, capsaicin releases substance P from the peripheral sensory
neurons.
With time, substance P becomes depleted, and capsaicin prevents
reaccumulation of substance P.
What is Substance P?
Substance P is a chemomediator responsible for pain
transmission from the periphery to the central nervous system (CNS).
Capsaicin Dose
Capsaicin is available as an over-the-counter (OTC) product in a patch, cream, gel,
liquid, or lotion.
Effect seen after 2-4 weeks of use
Capsaicin Contraindications, Adverse Events
Contraindication: None.
SE: burning and irritation at the application
site.
Oral NSAID MOA
One is by
inhibiting the conversion of arachidonic acid to prostaglandin, prostacyclin, and thromboxanes—
all of which are mediators of pain and inflammation. The other is by interfering with protein
kinase activation (especially when taken at higher doses).
Most non-selectively inhibit COX-1 and COX-2
What is COX?
The enzyme that converts arachidonic acid to prostaglandin G2.
What does COX-1 do?
COX-1 enzymes are found in
the gastrointestinal (GI) tract and kidney and produce protective prostaglandins,
What does COX-2 do?
COX-2 produces protective prostaglandins in
the kidney that are responsible for maintaining adequate blood perfusion via vasodilation of the
afferent arteriole.
Inhibition of COX-2 produces antiinflammatory
and analgesic effects without affecting the GI tract.
NSAID Contraindications
Pregnant women
Caution with liver or kidney disease
Aspirin allergy
EtOH dependence
all NSAIDs carry a black box warning emphasizing that they are contraindicated for
perioperative pain treatment in patients undergoing coronary artery bypass graft surgery and
should be avoided in patients with cardiovascular disease or risk factors.
What is a COX-2 selective NSAID?
Celecoxib (Celebrex)
Nonacetylated Salicylates Use
For those who are sensitive to the GI irritation caused by long-term ASA use
Diflunisal (Dolobid) Nonacetylated Salicylate MOA
Effective COX-1 inhibitor with antiinflammatory and analgesic properties, but its antipyretic activities are weak.
Acetaminophen (Tylenol) Indications
For patients with limited pharmacologic options due to intolerance or contraindications to the use of NSAIDs
Best for short term use
Risk of hepatotoxicity
Acetaminophen (Tylenol) MOA
Acetaminophen exerts its action within the CNS. It is thought to inhibit central COX, which
results in decreased prostaglandin synthesis. Through this prostaglandin inhibition,
acetaminophen exerts analgesic and antipyretic effects but does not have antiinflammatory
effects.
Analgesics in OA Indications
When the pain associated with OA progresses and is no longer responsive to acetaminophen or NSAIDs, analgesics are an option.
For those who have contraindication to NSAID or cannot tolerate them
Acetaminophen (Tylenol) Drug Interactions
Warfarin.
With chronic doses of greater than 1.3 g daily, acetaminophen can increase the international
normalized ratio (INR) of a patient on warfarin.
Tramadol (Ultram = extended release, Ultracet = tylenol combo) MOA
Tramadol exerts multiple effects to induce pain relief. It is a mu-opioid
receptor agonist similar to other opioids such as morphine. By binding to the mu-opioid receptor,
ascending pain pathways are inhibited, resulting in decreased pain sensation. In addition,
tramadol also inhibits the reuptake of serotonin and norepinephrine. These neurotransmitters are also involved in the ascending pain pathway.
Tramadol Contraindications
Sz d/o - lowers Sz threshold
EtOH dependence - CNS effects
Opioid Dependence - acts on opioid receptors
Tramadol Interactions
Tramadol is metabolized by CYP2D6, and any medication that inhibits or induces
this enzyme will interact with tramadol.
Inhibits serotonin reuptake, tramadol
has the potential to induce serotonin syndrome when used in combination with other serotonergic
agents, such as selective serotonin reuptake inhibitors, tricyclic antidepressants, monoamine
oxidase inhibitors, or linezolid.
Duloxetine MOA
Duloxetine is a serotonin and norepinephrine reuptake inhibitor. By enhancing serotonin and norepinephrine, duloxetine works in the CNS to reduce pain transmission.
Duloxetine Dosing
Food and Drug Administration (FDA) for chronic
musculoskeletal pain is 30 mg orally daily for 7 days and then increased to 60 mg orally daily,
Duloxetine Contraindications
Due to the risk for serotonin syndrome, duloxetine should not be started
while a patient is on a monoamine oxidase inhibitor (MAOI) or within 14 days of stopping an
MAOI.
If current linezolid IV therapy or methylene blue IV therapy
Duloxetine Adverse Effects
precautions and warnings associated with duloxetine risk include
hepatotoxicity, orthostatic hypotension, serotonin syndrome, abnormal bleeding, and activation
of mania.
Intra-articular Therapy for OA: Indications
If symptoms of OA are restricted to one or two joints that have not responded to first- or second-line treatment, intra-articular corticosteroids may be helpful.
First-Line Therapy for OA
The EULAR
continues to recommend acetaminophen as first-line therapy for hip and knee OA (last updated
in 2005 and 2003 respectively). Due to questionable efficacy and risk for hepatotoxicity, more
recent guidelines recommend topical therapies as first line
Second-Line Therapy for OA
Oral Non-selective NSAIDs
COX-2 inhibitor for those with GI issues
Gout Definition
Gout is an inflammatory condition that results from monosodium urate crystals precipitating in the synovial fluid between joints due to hyperuricemia.
Gout Pathophysiology
The monosodium urate crystals form due to hyperuricemia either from overproduction or from under-excretion of uric acid.
Gout Commonly affected Joints
Most Common: metatarsophalangeal joint.
Midtarsal joints, ankles, knees, fingers, wrists, and elbows.
Gout Diagnostic Criteria
Diagnosis of gout usually occurs clinically when a patient is experiencing rapid monoarticular arthritis, typically in the first metatarsophalangeal joint. This arthritis is accompanied by swelling and redness of the joint.
Xanthine Oxidase Inhibitors (Allopurinol, Febuxostat) for Chronic Gout MOA
XOIs decrease uric acid levels by selectively inhibiting xanthine oxidase.
Xanthine oxidase is the enzyme responsible for the conversion of hypoxanthine to xanthine to
uric acid. Hypoxanthine and xanthine are then excreted in the urine with little risk of
precipitation.