Exam 2 - Medchem 753, Delander Gout Flashcards
What is gout?
Inflammatory disease that results in urate crystals in joints and soft tissues
What causes the formation of crystals in gout?
Crystals form due to improper handling of uric acid which causes a supersaturated solution of urate precipitating crystals
How many people in the US are affected with Gout?
8 million (4% of population)
What factors are associated w/or are aggravated by Gout?
Genetics (big) Obesity (Surface area?) Age (older worse) Adult Males Potmenopausal women HTN Diet (high purine or high fructose)
What disease states might Gout be more prevalent in?
Lesch-Nyhan Syndrome
End Stage renal disease
Cancers w/ cell lysis
Major Organ Transplant
What Drugs may induce or exacerbate the presence of Gout?
Thiazides (Diuretics) - compete for transporters Low dose Aspirin Niacin Immune Suppressants Cytotoxic agents causing cell lysis
What is Lesch-Nyhan Syndrome?
A disease characterized by a lack of HGPRT which results in problems in the breakdown and removal of Urate. It is a Problem w/ Metabolic Process that some people have that does not have salvage pathway which results in higher amounts of Uric Acid and gout like symptoms.
What are the disease stages of Gout?
Acute
Intermittent
Chronic
When do Acute phases of Gout generally occur?
At night while asleep, while not moving, increased likelihood of crystalizing out due to things cooling down.
What are the common characteristics of acute gout?
- Crystals form in joint(Very common in big toe)
- low grade fever
- typically resolves in 3-14 days
- May not have another attack for quite a while or ever
- Intense pain
What are the common characteristics of intermittent gout?
- Acute attacks x2 or more per year
- Usually in more than one joint (not always toe)
What are the common characteristics of chronic Gout?
Means that something is happening w/ disease state to cause other problems
- Start therapy
- Changes in renal
- permanent crystals setting in joints
- generally polyarticular (many joints)
What affect does change in diet have on disease state?
Generally very minimal effect
Where do Purines come from?
- Our cells, constantly breaking down and forming it
2. Food
What is the enzyme animals have to break down Uric Acid?
Uricase (urate oxidase) which breaks down urate into Allantoin
What animal species do not contain Uricase?
Humans, Apes and Dalmations (dog)
What percentage of Uric Acid enters the Proximal tubule from glomerulus?
100%
What percentage of Uric Acid is reabsorbed by glomerular filtration?
98-100%
Due to secretion and reabsorption of Uric Acid, what percentage of Uric Acid is actually excreted in Urine?
8-12%
Due to secretion and reabsorption of Uric Acid, what percentage of Uric Acid is actually excreted in Urine?
8-12%
increasing is current area of drug research
What are Inflammasomes?
When there are high levels of Uric Acid in plasma, the uric acid cystallize and are phagocytized and form these, which release IL-1b, which activates a huge inflammatory response.
How much Uric Acid is the “magic number”? At what level is treatment usually started?
~7mg/dL
What are the chronic problems of gout that we are worried about with managing Gout?
- Renal - Nephrolithiasis (stones) and Interstitial Nephritis
- Arthritic - Deposition of Tophi, erosion of Cartilage and bone, loss of function
- Metabolic - associated w/ metabolic syndrome, stroke and other CVD
What is the gold standard in diagnosing Gout? What else is used?
Visualization of Uric Acid Crystals in aspirated synovial fluid
Differential Diagnosis by using colchicine to treat
What are the treatment goals of Acute Gout?
Resolve inflammatory process rapidly
What are the treatment goals of intermittent/chronic Gout?
Decrease Uric Acid so we don’t have long term problems of effects
New Guidelines state we don’t try to control serum level, we treat to control symptoms.
What medication has traditionally been the go to therapy for Acute flares of Gout? Why is it no longer? What is the first line according to guidelines now?
Colchicine, Price
Steroid then NSAID
Colchicine
- MOA
- Dosing
- SE
- Considerations
- Decrease Microtubule formation, which limits chemotaxis
- (1.2mg, prn 0.6mg an hour later) effective for 36hrs (1.2mg/day generally for 14 days)
- GI upset (25%), Muscle Weakness (inc w/ statins), Bone Marrow Suppression (penias)
- Price, Dose adjustments w/ Hepatic failure, inhibits 3A4 & PGP
What other drug classes are often prescribed for acute Gout flares?
NSAIDS Steroids IL-1 Antagonists (off label) Adrenocorticotropic hormone (ACTH) Opioids (?)
When using NSAIDS to control Gout:
what Med do you not want to use, what is traditionally used, what is common now?
- Don’t use Salicylates (Acetaminophen no effect, not an NSAID)
- Historically use Indomethacin
- Now Naprosyn or Naproxen common
- Any can be used
When using Steroids to control gout,
What is most common? dosing?
Prednisilone, 0.5mg/kg (~35mg/day) orally for 5 days, although can be given injection
Interleukin 1 antagonists
Anakinra and Canakinumab
- Not a lot known SE wise because they are rarely used,
- Thought to stop Interleukin-1b from causing inflammasome response
- Expensive as fuck
Adrenocorticotropic Hormone in treatment of Gout
Increases availability of cortisol (endogenous steroid)
Opioids in treatment of Gout?
Only treats the symptoms, covers up the pain.
What behavioral changes can be adopted?
- Weight loss
- Diet (avoid foods high in purines, adequately hydrated)
- Watch for Drugs that may aggravate
Historically doesn’t change a ton and is rarely adequate by itself
When is chronic treatment generally pursued?
Increase in Uric Acid levels above 7mg/dL AND:
- When patient is fed up with acute flares
- > 2 flares per year
- Tophi present
- Kidney disease/presence of stones
When you pursue Chronic therapy, what is a common side effect?
Increased incidence of acute flares within 6months of therapy
Does pH have anything to do with acute flare ups?
Delander, doubtful, but it may increase amount of stones
When you pursue Chronic therapy, what is a common side effect?
Increased incidence of acute flares within 6months of therapy (prophylaxis of acute attacks required)
Does pH have anything to do with acute flare ups?
Delander, doubtful, but it may increase amount of stones.
Otherwise don’t know
What are common Xanthine Oxidase inhibitors?
Allopurinol
Febuxostat
Allopurinol
- MOA
- Dosing
- SE
- Considerations
- Is a purine and uric acid analog inhibitor, inhibits the Xanthine Oxidase, decreasing the amount of uric acid produced.
- initially 100mg/day, increase by 100mg weekly, usually 300mg, max 800mg]
- Rash, Fever, GI, malaise, itching
- Hypersensitivity (Steven Johnson), DDI (Azathioprine & Mercaptopurine) 80% renal clearance (adjust renal impairment)
How to minimize the side effects of allopurinol?
- slow titration of medication
Hypersensitivity: - Limit use in HLA-B 5801 allele pts
What populations more commonly express HLA-B 5801 allele?
Asians
- Thai
- Han Chinese (Taiwan)
- Koreans
What drugs should not be used alongside Allopurinol or Febuxostat?
Azathioprine
Mercaptopurine
Febuxostat in the control of Gout
- MOA
- Dosing
- SE
- Considerations
- Non-purine inhibitor, non-competitively inhibits Xanthine Oxidase to reduce amount of Uric Acid produced
- 40mg/day up to 80mg/day, max 120mg
- Rash, Fever, GI, malaise, itching
- No hypersentivity rxn, Primarily Hepatic metabolism
What uricosuric agents are used to control gout?
Probenecid
Lisinurad
Probenecid
- MOA
- Dosing
- SE
- Considerations
- Relatively non specific transport inhibitor (facilitate excretion)
- usually 250mg bid, up to 2000mg
- Rash; GI
- DDI (Beta lactams, Methotrexate); Contraindicated in low CrCl (<50mL/min), those with G6P dehydrogenase deficiency
What populations are generally deficient for G6P dehydrogenase?
Mediterraneans
Blacks (10%)
Lisinuard
- MOA
- Dosing
- SE
- Considerations
- Inhibits Uric Acid Transporter 1 (URAT-1), reduces reabsorption from proximal tubule (facilitate excretion)
- 200mg/day
- Headache, Malaise, GERD
- Renal Failure in monotherapy
What Drug class must accompany the use of Lisinurad?
Xanthine Oxidase Inhibitors
When using Uricosurics, what counseling point is of the utmost importance?
Adequate Hydration
If Disease state does not respond to Xanthine Oxidase inhibitors or Uricosurics what is another option? Why is it not common?
Recombinate Uricase
Expensive as fuck
Exceedingly immunogenic
Rasburicase and Pegloticase
Rasburicase (only available w/ infusion)
Pegloticase (Pegylated uricase in order to not have a huge immune response)
