•Red : important •Black : in male / female slides •Pink : in female’s slides only •Blue : in male’s slides only •Green : Dr’s notes •Grey: Extra information, explanation Editing File

LECTURE 5: DRUGS IN GOUT

NOTE: In this lecture anything that’s written in red or green is the female’s Dr. notes Anything written in purple is the male’s Dr. notes OBJECTIVES:

✓ Identify the mechanism of action of drugs used for treatment of Gout. ✓ Classify drugs used for treatment of Gout. ✓ Outline the stages of Gout and the therapeutic objectives in each stage. ✓ Describe drug and non drug treatment of gout. ✓ Study in details the pharmacology of drugs used for treatment of gout. Overview of Gout

What causes gout? Gout

definition Pathogenesis Types

Primary Gout (genetic): Gout is usually Deposition of hereditary error of purine characterized by sodium urate metabolism. recurrent attacks of crystals in articular,

acute inflammatory periarticular, and Secondary Gout arthritis with red, subcutaneous (acquired): tender, hot and swollen tissues. (not to confuse it with pseudogout which is drugs that inhibit uric joints. characterized by deposits of calcium pyrophosphate) acid excretion or increase rate of cell death e.g. chemotherapy or another acquired disorder. (Chemotherapy works by killing cells using cytotoxic agents, this causes the release of purines such as Adenine and Guanine, the end product of their catabolism is uric acid).

Untreated Gout leads to:

Tophaceous: Nephrolithiasis: Masses of MSU crystals (Tofi) Renal stones caused by the 70% Uric acid (Monosodium urate) in cartilages , excreted by the kidney and 30% by gut joints , subcutaneous tissues . elimination

Urate Nephropathy : Joint inflammation Renal failure caused by and cardiovascular damage high levels of uric acid in advanced stages

joint inflammation

Tofi

Nephrolithiasis ❖ Epidemiology : Gout was historically known as "the disease of kings" or "rich man's disease." • Prevalence of hyperuricemia 5% . Not all of them will develop the disease. • Prevalence of gout 0.2% • Male to female ratio 10:1

❖ Pathophysiology : • gout is due to: 1- overproduction of uric acid (Uricostatic) 2- underexcretion (Uriocosuric) •Urate crystals are initially phagocytosed by synoviocytes, which then release prostaglandins, lysosomal enzymes, and interleukin-1 (inflammatory mediators) which attracts and activates polymorphonuclear leukocytes (PMN) and mononuclear phagocytes (MNP) (macrophages). This is why we use NSAIDs. • Attracted by these chemotactic mediators, polymorphonuclear leukocytes and mononuclear phagocytes migrate into the joint space and amplify the ongoing inflammatory process. • In the later phases of the attack, increased numbers of mononuclear phagocytes (macrophages) appear, ingest the urate crystals, and release more inflammatory mediators

❖ Stages of gout:

1 2 3 4 Asymptomatic Acute flares Intercritical chronic gout hyperuricemia (intermittent Gout (complication) gout) Acute The interval Long-term gout Elevated inflammation in between acute complication serum urate joint caused by flares Management: with no clinical free urate -Prevent manifestation crystals Management: of gout . Management: complications prevent Tophi,deposition Terminate the recurrent of crystals in Treat or not to attack. attack kidney” treat ? (Symptoms start -lower serum at this stage). uric acid

Asymptomatic Hyperuricemia • Hypertension >7 mg/dl (M) causes • CV Disease >6 mg/dl (F) • Stroke • Renal Disease • Metabolic Syndrome Treatment of Gout:

Treatment of Gout

Non-pharmalogic Pharmalogic

Uricostatic Uricosuric Tubulin Anti-inflammatory ‘Decreases “Increases inhibitors Lifestyle production’ excretion” modifications: - Loss of weight. - Exercise. - Diet Control. Allopurinol Probenecid NSAIDs Colchicine - Smoking cessation - Avoid eatables Sulfinpyrazone Steroids sweetened with fructose, Febuxostat full-fat dairy products . and avoid alcohol.

What is the management of gout? or any disease. 1- Non-pharmacological treatment first 2- pharmacological treatment second

● Aim of Pharmacotherapy: Most therapeutic strategies for gout involve lowering the uric acid level below the saturation point (<6 mg/dL), thus preventing the deposition of urate crystals. This can be accomplished by: (how these drugs work) 1- Interfering with uric acid synthesis with allopurinol, Febuxostat. 2- increasing uric acid excretion with probenecid or sulfinpyrazone. 3- Inhibiting leukocyte entry into the affected joint with colchicine. 4- Administration of NSAIDs. such as naproxen and ibuprofen in HIGH doses (Anti-inflammatory and analgesic effects)

“Classification of drugs”, it’s important to know the drug and the Treatment of Acute Gout: group it belongs to ● To stop inflammation ● The most commonly used first-line treatment.(because they relieve pain) ● Head-to-head studies show few differences between drugs. NSAIDs (Drugs of this class are similar). ● Full Doses of NSAIDs should be initiated immediately and tapered after resolution of symptoms. (we do not start with small doses) (keep in mind that one of the ADRs of aspirin is acute gouty arthritis when given in low doses)

1- GI ulcer. 2- Bleeding or perforation. Contraindicated 3- Renal insufficiency. 4- Heart Failure. 5- Use of oral anticoagulants. (Increases bleeding). *Recall Lecture 2 NSAIDs Cont. ● Corticosteroids are a good alternative where NSAIDs and colchicine cannot be used or in refractory cases. (Resistance case) Steroids ● Studies showed equal efficacy between corticosteroids and (Stronger than NSAIDs) NSAIDs, with no reported side-effects with short-term use of corticosteroids.

● In elderly people, patients with with liver or hepatic impairment, Uses IHD (Ischemic heart disease), PUD (Peptic ulcer disease), Hypersensitivity to NSAIDs.

● Intra articularly (preferred route if one or two joints are affected). Route of long use causes joint damage and increased risk of infections leading to severe arthritis. Administration ● Orally. ● Intramuscularly or intravenously.

Cont.

● Origin: Colchicine Alkaloid obtained from autumn crocus (flowering plant). ● (Very important) The effect: Minimal effect on uric acid synthesis, excretion & is not analgesic.

● Binds to microtubules in neutrophils. ● Inhibits cell division by:(Mitosis) Mechanism ● Inhibits chemotactic factors. ● Inhibits inflamosomes & IL-1 production. (inflamosomes What is the Main mechanism are inflammatory proteins) ? Microtubules inhibitor Colchicine relieves a painful gouty attack by going to work right in the joint (localized). It (Antimitotic drug) can have you running smoothly again.

● Route of Administration: orally.(I.V causes diarrhea,bone marrow suppression increase) ● Absorption: rapidly absorbed from the GI tract. ● Half-life: reaches peak plasma levels within 2 hours. Pharmacokinetic ● Recycling: in the bile. (Enterohepatic circulation). ● Excretion: unchanged in the faeces or urine. ● Should be avoided in: patients with a creatinine clearance of less than 50 mL/min. (Renal diseases patients).

1. Treatment of gout flares.(Acute) 2. Prophylaxis (Prevention) of gout flares. (In between Clinical Uses attacks) 3. Treatment of Mediterranean fever.

1. Abdominal: Diarrhea (sometimes severe and bloody, the patient stops taking the drug), Nausea, Vomiting, Abdominal Cramps, Dehydration. Side Effects 2. Immune: Bone marrow depression. (may cause hair fall like in chemotherapy).”because they are anti-mitotic important drugs” 3. Cardiac (large doses): Cardiac toxicity, arrhythmia, Vascular collapse, Hepatotoxicity, alopecia. Uric acid synthesis inhibitors: Allopurinol, Febuxostat

Mechanism of ● Inhibit Xanthine oxidase. Action Hypoxanthine Xanthine Uric acid

● Allopurinol not active is metabolized by xanthine oxidase into alloxanthine (oxypurinol) which is pharmacologically active

P.K ● Absorption 70% Pharmacokinetics ● Protein Binding negligible 5% ● Hepatic metabolism, 70% converted to active metabolite (Oxypurinol) which is eliminated unchanged in the urine.

1-Diarrhea,nausea,abnormal liver tests. 2-Acute attacks of gout. explained in the green note below ADRS 3-Fever,rash,*toxic epidermal necrolysis (Severe ADRS), These side effects hepatotoxicity, marrow suppression vasculitis. are due to the active 4-DRESS syndrome (Drug reaction, Eosinophilia,Systemic metabolite Symptoms). Alloxanthine 5-20% mortality rate. (Oxypurinol) 6- Allopurinol hypersensitivity syndrome

ﺑداﯾﺔ اﻟﻌﻼج ﻣﻣﻛن ﺗﺣﺻل ھﺟﻣﺎت ﻟﯾش ؟ ﻷن آﻟﯾﺔ ﻋﻣل اﻷدوﯾﺔ اﻧﮭﺎ ﺗﻘﻠل ﻣن اﻟﯾورﯾك أﺳﯾد اﻟﻠﻲّ ﺑﺎﻟدم ف اﻟﯾورﯾك أﺳﯾد اﻟﻠﻲّ Toxic epidermal* ﻓﻲ ال tissue راح ﯾﺣﺻل ﻟﮫ necrolysis causes mobilization وﯾرﺟﻊ ﯾدﺧل اﻟدم ﻣن ﺟدﯾد ﻓﺗﺣﺻل اﻟﮭﺟﻣﺎت ulcers which leads to infections. Drug Allopurinol Febuxostat

● Management of hyperuricemia ● Indicated for the of gout. Mainly management of ● Uric acid stones or hyperuricemia in patients nephropathy. with gout (as it reduces serum Clinical ● It is a drug of choice in patients uric acid levels). Uses with with both gout & ischemic ● Chemically distinct from heart disease allopurinol (non purine). ● Severe tophaceous ● Can be used in patients deposits.(uric acid deposits in with renal disease. tissues). ● Oral specific xanthine ● Management of hyperuricemia oxidase inhibitor. associated with chemotherapy. More specific than allopurinol ● Prevention of recurrent calcium oxalate kidney stones.

(when cells are destroyed, lots of purine is diffused).

● Metabolism: it is metabolized ● Route of administration : by xanthine oxidase into Given orally once daily. alloxanthin which is ● Absorption: well P.K pharmacologically active (The absorbed(85%). active metabolite inhibits the ● Metabolism: Metabolized in enzyme). liver,mainly conjugated to ● Absorption 70% glucuronic acid ● Protein Binding negligible 5% ● Protein BInding: 99%. ● Hepatic metabolism, 70% ● Half life: (Girls slide:8 hrs, converted to active Boys slide :4-18 hrs) metabolite(Oxypurinol) ● Given to patients who do which is eliminated not tolerate allopurinol. unchanged in the urine. ● High dose of febuxostat have a lesser effect than the lowest dose of allopurinol.

The side effects are due to the active metabolite which are: ● Increases number of gout ● Allopurinol Hypersensitivity attacks the first few months Syndrome of treatment. ● ADRs Toxic Epidermal Necrolysis ● Increases level of liver ● DRESS Syndrome (Drug enzymes. Reaction Eosinophilia Systemic ● Nausea, diarrhea. Symptoms) 20% mortality rate. ● Numbness of arm or leg. ● Fever, rash, marrow ● Headache suppression,diarrhea,nausea, abnormal liver tests & vasculitis, acute gout attacks and hepatotoxicity Cont.. •Warfarin & dicumarol: inhibiting the metabolism of a inhibits their metabolism drug increases the (Bleeding) drug’s action Drug interactions •6-mercaptopurine and For Allopurinol only azathioprine (anti-cancer drugs): Reduces their metabolism •Ampicillin : Increases frequency of skin rash

What is the drug of choice for a patient with ischemia and gout ? Allopurinol

What is the drug of choice for a patient with a renal disease? Febuxostat

Uricosuric Drugs

Mechanism of action Effect Contradiction

● Blocks tubular 1-Control hyperuricemia 1-Patients with renal reabsorption of uric and prevents tophus disease. acid and enhances formation. 2-History of nephrolithiasis. urine uric acid 2-Increases risk of 3-Recent acute gout excretion. nephrolithiasis. 4-Less effective in elderly the excreted urine is high in patients. uric acid which leads to the formation of kidney stones that’s why some of these drugs cannot be given to patients with renal disease. 3-Some drugs reduce efficacy (e.g, aspirin).

Important DON’T FORGET TYPES OF URICOSURIC DRUGS

Drugs Probenecid Sulfinpyrazone

ADRS (side effect): •Can aggravate peptic ulcer Features •Exacerbation of acute attack disease. •Risk of uric acid stone • Aspirin reduces efficacy of • GIT upset sulfinpyrazone. • Allergic rash. • Enhances the action of certain anti-diabetic drugs.Lower blood glucose

Probenecid inhibits Urate Sulfinpyrazone inhibits URAT1 MOA Transporters (URAT) in the & OAT4. (Organic acid apical membrane of the transporter 4) (responsible for (Mechanism of proximal tubule It also inhibits reabsorption of uric acid) action) organic acid transporter(OAT) → ↑ plasma concentration of penicillin

Effect 1-Moderately effective. Pegloticase

•A uric acid specific enzyme which is a recombinant Mechanisms modified mammalian uricase enzyme through genetic engineering • Enzymatically converts uric acid to allantoin, which is more soluble and readily excreted in the urine. ﻛﺄﻧﮭﺎ اﻟن ﺗﻠﯾﻧﯾن ﻓﺗﻠﯾن وﺗﺻﯾر ﺳﺎﯾﻠﺔ وﺗطﻠﻊ ﻣن اﻟﺟﺳم

Used for the treatment of chronic gout in adult patients refractory to conventional therapy. Expensive therapy Clinical use

● Route of administration: IV P.K ● peak decline in uric acid level within 24-72 hours (Pharmacokinetics) (Rapid decrease, and this is an advantage)

•Infusion reactions. Fever and skin rash •Anaphylaxis. Life threatening ADRS •Gout flare Adverse drug •Arthralgia (arthra: joints, algia: pain) reactions •Muscle spasm. During infusion and after it •Nephrolithiasis

Uric Allantoin Acid

Uri- case Pegloticase

Renal GIT Circulating excretion excretion In excess

Tophi Urate Deposition SUMMARY Summary table from team 437

Nonphar- macologic

Pharmacological Treatment of gout QUIZ

MCQs

1-Which of the following causes the inflammatory process in Gout? A-Deposits of Sodium Urate Crystals B-High serum Uric acid C-Cytokines

2-A 50 years old man came to the ER complaining from severe pain in his toes joints with hotness on them. Blood sample was taken from him and it revealed high uric acid with creatine clearance rate of 23 mL/min. Which of the following should be avoided in treating his Gout? A-NSAIDs B-Colchicine C-Febuxostat

3-Allopurinol is metabolized into Alloxanthin by A-Aspirin B-Xanthine oxidase C-Pegloticase

4-Jamal is a 35 years old man with known history of Gout was diagnosed with bacterial infection and was prescribed penicillin. Which drug of Gout his doctor must stop it in this case due to interaction ? A-Probenecid B-Febuxostat C-Steroids

5-If a Gout patient has ischemic heart disease, what is the drug of choice? A-Pegloticase B-Allopurinol C-Colchicine 1-A 2-B 3-B 4-A 5-B QUIZ

SAQ

A- What are the stages of Gout? Four distinct stages: a) asymptomatic hyperuricemia b) acute intermittent gout c)Intercritical stage d) chronic gout

B-How to manage each stage? Asymptotic: Life style modification Acute: terminate the attack Intercritical: Prevent the recurrent attacks Chronic: prevent complication and lower serum uric acid

C-In Gout we have acute treatment and prophylactic therapy. According to the previous statement, answer the following: ● Write Colchicine mechanism of action and clinical uses: Slide 6 in Colchicine part.

● Mention one class that is used a preventive therapy with two ADRs: Any class with its ADRs

D- Give a short answer about the metabolism of allopurinol. It is metabolized by xanthine oxidase into alloxanthin which is pharmacologically active. GOOD LUCK

Team Leaders: Nouf Alshammari Zyad Aldosari

Team Members: Alwaleed Alsaleh Talal Abozaid Muhannad Makkawi

Sources: Team 435 Team 437