Gout Flashcards
Hyperuricemia levels
> 6.8 mg/dL
Gout results from increased levels of __________ in blood
uric acid
Gout is known as the deposition of ______________ in synovial fluid or tissue
monosodium urate crystals
Serum Urate Concentrations will increase with what factors?
- age
- body weight
- gender (male)
- alcohol
- blood pressure
Humans (and apes) are at higher risk of gout because they do not make the ___________
uricase protein (pseudogene)
Uricase prevents ________ being made from ________
fat; sugar
Hypoxanthine gets made to xanthine by what enzyme?
xanthine oxidase
Xanthine gets made into Uric acid by what enzyme?
xanthine oxidase
Uric acid is (more or less) soluble than hypoxanthine and xanthine
less soluble!
Monosodium urate crystals can form when (low or high) plasma urate concentrations are present
high
Uric acid is made into Allantoin by the __________ enzyme
uricase
Uricase makes uric acid into ________
allantoin
Uric acid is excreted _________
renally
What 3 things will inhibit De Novo Synthesis of Purines
AMP, IMP, GMP
(Increase or Decrease) PRPP synthetase activity (Increase or Decrease) De Novo Synthesis of Purines
Increase; increases
Adenine and Guanine are broken down to ____________
hypoxanthine
What is the recycle pathway in purine metabolism?
Hypoxantine is made into GTP
When HGPRTase activity is DECREASED - what 2 effects are seen
1) increases hypoxanthine oxidation to uric acid
2) stimulates De Novo Synthesis through accumulated PRPP
De Novo Synthesis of Purines:
PRPP —–10 steps—-> ___________
IMP (inosine monophosphate)
Urate crystals are taken up by ________cytes and ________cytes
monocytes; synoviocytes
Once synoviocytes have taken in urate crystals, they release what?
prostaglandins, lysosomal enzymes, and interleukin (aka cause inflammation)
Synoviocytes take in urate crystals, release contents, and then attract _________ to increase inflammation
neutrophils
Uricase converts uric acid to _________ which is (more or less) solbule
allantoin; more
Urate crystals aka monosodium urate will deposit in the _________, _________, and may cause ________ in the kidneys
joints, cartilage, caliculi
Features of Acute Gout
- acute arthritis
- 1st metarsophalangeal joint
- excruciating pain
Medication options for Acute Gout (Hazbun Lecture)
1 - NSAIDs
2 - Colchicine
3 - Glucocorticoids
Medication options for Chronic Gout (Hazbun Lecture)
allopurinol/Febuxostat;
Probenecid; Pegloticase
What are features of chronic gout?
Hyperuricemia; development of tophi; recurrent attacks of acute gout
Primary Gout vs Secondary Gout
Primary - happens because of overproduction or decreased secretion of uric acid
Secondary - uric acid increases due to cell death/lysis because nucleic acid is released
Reasons Primary Gout can occur
Ethanol, foods high in purines, Obesity
Why Does Ethanol increase uric acid levels
- increases purine catabolism in liver
- increases lactic acid which inhibits urate secretion
(ethanol competes with uric acid —> uric acid get secreted)
what are some foods high in purines
red meat, seafood
Reasons Secondary Gout can occur
- chemotherapy
- Myelo- and lymphoproliferative disorders
- Polycythemia vera and anemia
- Psoriasis
2/3 of Uric acid is excreted in the _______
kidneys
90% of uric acid is __________ in the ________ tubule
reabsorbed; proximal
How to tell if a patient with Hyperuricemia is a overproducer or underexcretor?
- put on purine free diet
- measure amount of uric acid in urine for 24 hours
- if excreting < 600 mg = underexcretor
- if excreting > 1000 mg = overproducer
Drugs that can induce Hyperuricemia
- Diuretics (thiazides and loops)
- Nicotinic acid
- Salicylates
- Ethanol
- Cyclosporine
- Pyrazinamide
- Levodopa
- Ethambutol
- Cytotoxic Drugs
- Urate lowering therapies
Patients will be (asymptomatic or symptomatic) between flare ups
asymptomatic
Clinical Presentation of Gout:
Fever, intense pain, erythema, warmth, swelling, and inflammation
Definition of Podagra
gout involving first metatarsophlalangeal joint “the great toe”
Definition of Tophi
deposits of monosodium urate in cartilage, tendons, synovial membranes
Gout is more common in (lower or higher) joints
lower
why is gout more common in lower joints?
- lower temp
- are more of the “weight bearing joints” during the day
most flare ups happen during what time of the day?
nighttime/when you are sleeping!
Uric acid nephrolithiasis:
if urine is (acidic or basic) the uric acid is (less or more) soluble which leads to a risk of increased stone formation
acidic; less
Uric acid nephrolithiasis is more common when urine pH is < _____
6
What are the 3 long term conditions of Gout
- uric acid nephrolithiasis
- tophaceous gout
- gouty nephropathy
what is tophaceous gout?
late complication of gout; seen at base of great toe, helix of ear, bursae, achillies, knees, wrists, ankles
Joint destruction, pain and nerve compression syndrome
Gouty Neprhopathy can be acute or chronic:
Facts about Acute Gout Nephropathy?
- urine flow is blocked bc of uric acid precipitation collecting ducts/ureters
- acute renal failure can occur
- seen in ALL/CLL/CML pts
Gouty Neprhopathy can be acute or chronic:
Facts about Chronic Gout Nephropathy?
- LONG TERM deposition of urate crystals in renal system
- proteinuria can occur
- assoc. w/ HTN, DM, atherosclerosis
What are some Non-Pharmacotherapy options to help with asymptomatic or symptomatic hyperuricemia
- reduce purines rich foods
- reduce fructose containing products
- increase fluid intake (to decrease risk of nephrolithiasis)
- increase consumption of low-fat or nonfat dairy products
- encourage weight loss
- rest joint 1 - 2 days/ice it/AVOID HEAT
Two main agents used to treat ACUTE GOUT
- colchicine
- NSAIDs
Colchicine - (does or does not) alter the metabolism of excretion of urates
DOES NOT (it just relieves pain and inflammation)
Colchicine inhibits inflammation by slowing down what?
slowing (their movement) down macrophages
MOA of Colchicine = ?
Colchicine binds to Tubulin –> no polymerization of tubulin occurs –> migration of leukocytes is inhibited –> decreased tyrsonie phosphorylation inhibits synthesis of LTB4
Drug interactions for Colchicine
- Cyclosporine/Tacrolimus (only) will cause colchicine to get excreted in the urine
- Cyclosporine/Tacrolimus/Verapamil will cause colchicine to get excreted in the bile
NSAIDs or Colchicine? which is preferred and why?
NSAIDs because they are less toxic than colchicine
NSAIDs: __________ can also increase ureate excretion in the urine
oxaprozin
2 main classes of drugs used to PREVENT Gout
Uricosuric Agents; Xanthine oxidase inhibitors
Which drugs are uricosuric agents
probenecid
sulfinipyrazone is but not used in practice anymore
Which drugs are Xanthine oxidase inhibitors?
Allopurinol, Febuxostat
Why do Uricosuric Agents work to prevent gout? (aka what is its MOA)
Uricosuric drugs compete with uric acid @ site of reabsorption in renal tubule - therefore uric acid is not reabsorbed as much/uric acid IS renally excreted
Drug interactions for Uricosuric Agents:
________ decreases effectiveness of uricosuric agents by competing @ kidney
aspirin
Drug interactions for Uricosuric Agents:
Aspirin
it decreases effectiveness of uricosuric agents by competing @ kidney’s reabsorption
Probenecid blocks _________ of other drugs or metabolites (sulfamides, penicillins, cephalosporins)
urinary secretion
Drugs that interfere with the excretion of uric acid and therefore increase serum uric acid - are …?
diuretics, salicylates, nicotinic acid
Allopurinol is a ________ of hypoxanthine
isomer
Allopurinol is a isomer of _________
hypoxanthine
MOA of Allopurinol
Allopurinol is substrate of xanthine oxidase; allopurinol is made into oxypurinol; oxypurinol will tightly bind to xanthine oxidase and inhibits the enzyme
Difference b/w Allopurinol and Febuxostat (Uloric)
Febuxostat is a NON-PURINE inhibitor of xanthine oxidase
Uloric is metbolized by the ________ and excreted by the ________
liver; kidney
Uloric is (not very or very) strong at binding
very strong!! it can inhibit both the reduced and oxidized enzyme
Uloric may be advantageous in what kind of patients? (3 groups)
- pts w/ allopurinol hypersensitivity
- pts w/ reduced kidney function
- pts not responding o high doses of allopurinol
Krystexxa is brand for ?
Pegloticase
How does Krystexxa work to treat gout?
it is URICASE bound to mPEG; Uricase will oxidize uric acid to allantoin (a soluble product that can be excreted easily)
Krystexxa is CONTRAINDICATED for what pts?
pts that are G6P dehydrogenase deficient
which drug causes decreased immunogenicity
Krystexxa
Elitek is brand for?
Rasburicase
Elitek works how?
it is recombinant urate oxidase enzyme from aspergillus flavus - will catalyze the oxidation of uric acid to allantoin!
how are Kyrystexxa and Elitek administered?
by IV
Zurampic is brand for ?
Lesinurad
Zurampic works how?
it is a selective uric acid reabsorption INHIBITOR aka will block URAT1 transporter
Therapy goal for target serum uric acid < ___ mg/dL
6
3 main options for an acute gout attach
- NSAIDs
- colchicine
- corticosteroid
FDA approved NSAIDs for gout?
Indomethacin, naproxen, sulindac
Dose for Indomethacin for Gout
50 mg TID
Dose for Naproxen for Gout
750 mg followed by 250 mg PO q8H
Dose for Sulindac for gout
200 mg BID
NSAIDs for acute gout - how to take them
at SCHEDULED doses - not when feeling pain….
NSAIDs are contraindicated in what situations?
- pt has hypersensitivity to aspirin/NSAIDs
- decompensated HF
- Active peptic ulcer disease or GI bleed
- Severe or Acute Renal impairment
NSAIDs should be used with caution in what situations?
- if pt is using anticoagulants or antiplatelet drugs
- Hx of HF
- Hx of peptic ulcer disease or GI bleed
- Renal Impairment (CrCl < 50 mL/min)
- Uncontrolled HTN
Adverse effects of NSAIDs
GI effects and what to do to help prevent them?
can have Gastritis, bleeding, perforation
Consider PPI
NSAIDs will effect the Kidney and this can be seen by a (decreased or increased) _______
increased SCr
Colchicine should be started within ________ of attack onset
36 hours
when should colchicine be used?
when pts do not tolerate NSAIDs or pt has a contraindication to NSAIDs
Colchicine Dosing
LOADING and CONTINUING DOSE
Loading: 1.2 mg once then 0.6 mg one hour later
Continue: 0.6 mg PO QD or BID 12 hours after loading dose (depending on pt tolerability)
what 4 things would indicate dose adjustments to colchicine
- CrCl < 30 mL/min
- Dialysis
- Use of CYP3A4 inhibitors
- Use of P-glycoprotein inhibitors
How to dose Colchicine if pt has CrCl < 30 mL/min
- DO NOT repeat dose w/in 14 days
- Prophylaxis: 0.3 mg PO QD (instead of 0.6)
How to dose Colchicine if pt is on dialysis
Tx: 0.6 mg PO x 1 (DO NOT repeat dose w/in 14 days)
- Prophylaxis: 0.3 mg 2x a week
Adverse Effects of Colchicine
GI - Diarrhea; Nausea Vomiting
Bone Marrow Suppression - Aplastic Anemia; Thrombocytopenia
Neuromuscular - Myopathy, Rhabdomyolysis
Examples of Corticosteroids used for Gout
- Prednisone
- Methylprednisolone
- Triamcinolone
Corticosteroids are used for gout when…..
- NSAID/Colchicine intolerance
- Polyarticular involvement
- Resistant Cases
Dosing of Prednisone for Gout:
____ mg/kg per day for___ - _____ days followed by discontinuation
OR
____ mg/kg for ____ - ____ days followed by tapering for ____ - _____ days before discontinuation
- 5;5;10
0. 5; 2;5;7;10
Dosing of Triamcinolone Acetonide
____ IM once then oral prednisone as above
OR
____ - ____ intra-articular injection x1
60 mg; 2.5 mg; 40 mg
Adverse Effects of Corticosteroids
COMMON ones
______ in blood glucose
______ in appetite or weight gain
Dose Dependent ______ : ___/___/___
Fluid retention can lead to ________ or ____ concerns
CNS: HA, insomnia, mood swings, nervousness
increase; increase; GI upset; N;V;D; increase BP; HF
What are the less common adverse effects of corticosteroids
- neutropenia
- hepatotoxicity
- myleosuppresion
caution with glucocorticoids with situations?
- Diabetes
- HTN
- Peptic ulcer disease/GI bleed
- CHF
- Immunosuppression
- Psychiatric disorder
Possible Combination Therapy Options for ACUTE Gout ATTACKS
- Colchicine + NSAIDs
- Oral Corticosteroids + Colchicine
- Intra-Articular Steroids + all other modalities
(just not Oral steroid AND NSAIDs)
What are some disease states that are risk factors for Chronic Gout
- HTN
- Type 2 Diabetes
- Obesity
- Metabolic Syndrome
- CKD
When to start Urate Lowering Therapy: - Pt has Diagnosis of Gout AND one of the four other traits... what are the 4 other traits
- 2+ acute attacks per year
- Presence of Tophi
- CKD stage 2 or more
- Presence of Renal Stones
Urate lowering therapy is typically delayed for about ________ after acute attack resolution
2 weeks
Goals of Therapy in Urate Lowering Therapy
- Achieve a serum urate level < 6 mg/dL
- Prevent acute attacks
Monitoring in Urate lowering therapy
During initiation monitor urate every ________
Once urate levels are under 6 mg/dL - monitor every _______
2 - 5 weeks; 6 months
Agents that are used to Lower Urate Levels
1st line -
2nd line -
3rd line -
1st: Xanthine Oxidase inhibitors
2nd: Uricosurics
3rd: Uricase Agents
Why is Allopurinol first line Xanthine Oxidase Inhibitors
efficacy, availability, low cost
Starting Dose for Allopurinol
100 mg QD
Starting dose of Allopurinol for patients with CKD stage 4
50 mg QD
Max dose for Allopurinol
800 mg/day
Slow titration of Allopurinol is recommended every _______
2 - 4 weeks
Common Adverse Effects of Allopurinol
- Skin rash
- Itching
- Leukopenia
- Thrombocytopenia
- GI intolerance
Less Common Adverse Effects of Allopurinol
- Hypersensitivity
- Stevens-Johnson Syndrom o Toxic Epidermal necrolysis
- Eosinophilia
- Vasculitis
Allopurinol Drug Interactions:
- Warfarin (increase INR)
- Antacids
- Mercaptopurine and Azathioprine (because these also use Xanthine Oxidase)
Allopurinol Monitoring - _________ screening in at-risk populations
HLA-B*580 (if have this, most likely people of asian decent, can put at high risk for life threatening hypersensitivity)
Starting Dose for Uloric
40 mg QD
Max dose for Uloric
80 mg QD
which drug should NOT be initiated or discontinued during an acute attack
Uloric
Dose Adjustments for Uloric if renal or hepatic impairment
No dose adjustment - data is limited; use with Caution
Adverse Effects of Uloric
- rash
- nausea
- Abnormal LFTs
- Precaution for CV thromboembolic events (CV deaths, non fatal MI, non-fatal stroke)
Largest Limitation of Uloric is?
Cost
Things to Monitor when Pt is on Uloric
Check LFTs at baseline, 2 mos, 4 mos
Contraindications for Uloric
concomitant use with azathioprine, mercaptopurine, or theophylline
MOA for Uricosuric Agents
increases clearance of uric acid by inhibiting secretory reabsorption in the proximal tubule
When is Probenecid used?
- pts cant tolerate allopurinol
- pts cannot reach target urate levels with just a XOI
- pts have documented underexcretion of urate
What is brand for probenecid
Benemid
Can Probenecid be added to Allopurinol?
yes
Max dose of Probenecid
2 gm QD
Encourage _______ when on Probenecid
adequate hydration - to prevent renal stone formation
Dosing of Probenecid
TITRATE UP
250 BID x 7 then 500 BID x 14
Why start at a low dose with Probenecid
to prevent uricosuria and renal stone formation
Adverse Effects for Probenecid
- flushing
- HA
- pruritis
- GI upset
- STONE FORMATION
- Aplast Anemia/Leukopenia
Contraindications for Probenecid
- Hypersensitivity
- Salicylates
- Blood Dyscrasias
- Uric Acid Kidney Stones
- CrCl < 50 mL/min
- Acute Attack
Example of Uricase Agents
Pegloticase
MOA of Uricase Agents
converts Uric acid to allantoin (which is more SOLUBLE IN WATER)
Brand for Pegloticase
Krystexxa
Pegloticase is a ________ line agent
LAST
How is Pegloticase administered?
by IV
Dose for Pegloticase
8 mg IV infusion q 2 weeks
Administered over 120 minutes
for Pegloticase - Patients should be PRE-TREATED with what?
antihistamines and corticosteroids (bc of infusion related rxns)
When is Pegloticase indicated
for REFRACTORY GOUT
- pt with significant disease burden
or
pt has intolerance to conventional urate lowering therapy
Adverse Effects for Pegloticase
- infusion related rxns
- Anaphylaxis
- Nephrolithiasis
- Arthralgias
- HF exacerbation
- Nausea
Contraindications/Cautions for Pegloticase
- G6PD deficiency (bc puts them at risk for hemolysis and methemeoglobinemia - perform G6PD test)
- Caution: HF pts
Lesinurad is generic for ?
Zurampic
MOA for Lesinurad
URAT1 inhibitor - aka will enhance uric acid excretion
Lesinurad has been approved to be used in combination with what med?
XOI (xanthine oxidase inhibitor)
Dose of Lesinurad
200 mg QD PO
Adverse Effects for Lesinurad
BLACK BOX WARNING: for Acute Renal Failure
- HA
- GERD
Fenofibrate can be used for gout - how/what is the MOA
increases the clearance of both hypoxanthine and xanthine (decreases levels ~ 20 - 30%)
Losartan can be used for gout - how/what is the MOA
inhibits tubular reabsorption of uric acid
unique to losartan - no other ARB will do this
Fenofibrate or Losartan can be used to help with gout - can they be used with another gout med?
yes - XOI and one of those can be used for refractory cases
What are two off label drugs that can be used for gout
fenofibrate, Losartan
Options for Prophylaxis
- Colchicine (preferred)
- Low Dose NSAIDs
- Low dose Prednisone/Prednisolone (< 10 mg /day tho)
Prophylaxis regimen should be initiated along with _________
ULT (urate lowering therapy)
Colchicine dosing - Prophylaxis
0.6 mg PO QD or BID
colchicine is preferred over NSAIDs but both are first line options
Low Dose NSAIDs dosing - Prophylaxis
Naproxen 250 mg PO BID
Low dose Prednisone/Prednisolone dosing - Prophylaxis
ONLY if other options are contraindicated or not tolerated