How Do Antigout Agents Work?

Antigout agents are medications prescribed for the treatment of gout, a painful arthritic condition caused by excessive uric acid in the blood that gets deposited as monosodium urate crystals in joints. Gout most commonly affects the big toes, but can also affect other joints such as ankles, knees, elbows, wrists, and fingers.

Antigout agents work in different ways to decrease uric acid production in the body, deposition of urate crystals in the joints, and the inflammatory response that results. Antigout agents work in the following ways:

• Reduce uric acid production by inhibiting the activity of xanthine oxidase, an enzyme that synthesizes uric acid from hypoxanthine, a purine derivative. Purine is a naturally occurring chemical compound in the human body and is also found in many foods.
• Facilitate the excretion of uric acid by blocking its reuptake in the kidneys.
• Control inflammation by interfering with cellular functions that enable immune cells leukocytes and neutrophils to change shape, migrate to the joints, and release inflammatory substances in the effort to destroy the urate crystals.

Antigout agents may be administered as oral tablets, capsules or solutions, or intravenous (IV) injections to prevent and treat the following conditions:

FDA-approved:

• Gout flares
• Chronic gout
• Familial Mediterranean fever, an inherited autoinflammatory condition that causes inflammation in the abdomen, chest, and joints, and is accompanied by fever
• Chronic gouty arthritis
• Hyperuricemia (high uric acid levels in the blood)
• Antineoplastic-induced hyperuricemia, a condition caused by chemotherapy

Off-label:

• Post-STEMI (ST-elevation myocardial infarction) pericarditis, inflammation of the membrane around the heart (pericardium), a complication that occurs after a heart attack

Orphan designation:

• Behcet’s syndrome, a rare disorder that causes inflammation of blood vessels

Side effects of antigout agents may include the following:

• Gastrointestinal (GI) effects such as:
  • Nausea
  • Vomiting
  • Cramping
  • Abdominal pain and discomfort
  • Diarrhea
  • Lactose intolerance
  • Abdominal distention
  • Constipation
  • Dyspepsia (indigestion)
  • Flatulence
  • Frequent stools
  • Gastritis
  • Gastroesophageal reflux disease (GERD)
  • Hematemesis (blood in vomit)
  • Hyperchlorhydria (high hydrochloric acid secretion in the stomach)
  • Hematochezia (blood in stools)
  • Peptic ulcer
• Increase or decrease in appetite
• Weight gain or loss
• Anorexia (loss of appetite)
• Diabetes mellitus
• Hyperglycemia (high blood glucose levels)
• Hyperlipidemia (high levels of blood fats)
• Hypercholesterolemia (high blood cholesterol)
• Hypertriglyceridemia (high level of triglycerides in the blood)
• Hypokalemia (low potassium in the blood)
• Hepatotoxicity (toxicity to the liver)
• Liver function abnormalities
• Elevated liver enzymes
• Jaundice
• Hepatic steatosis (fatty liver)
• Hepatitis (liver inflammation)
• Hepatomegaly (liver enlargement)
• Hepatic necrosis (liver tissue death)
• Liver failure
• Cholelithiasis (gallstones)
• Cholecystitis (gallbladder inflammation)
• Pancreatitis (inflammation of the pancreas)
• Sore gums
• Dry mouth
• Mouth ulceration
• Pharyngitis (throat inflammation)
• Pharyngolaryngeal pain (throat pain)
• Throat irritation
• Pharyngeal edema
• Respiratory tract congestion
• Bronchospasm
• Dyspnea (shortness of breath)
• Cough
• Sneezing
• Bronchitis (inflammation of the bronchial passage)
• Nasal dryness
• Epistaxis (nasal bleeding)
• Paranasal sinus hypersecretion
• Upper respiratory tract infection
• Kidney function abnormality
• Tubulointerstitial nephritis (inflammation of the tubules and surrounding tissue in the kidney)
• Renal damage
• Renal insufficiency
• Renal failure
• Hematuria (blood in the urine)
• Oliguria (low urine output)
• Nephrotic syndrome/proteinuria (kidney disorder that causes excessive excretion of protein in the urine)
• Uric acid kidney stones with or without hematuria
• Renal colic and costovertebral pain (severe flank and upper back pain due to stone in the urinary tract)
• Pollakiuria (frequent urination)
• Urinary urgency
• Incontinence
• Headache
• Migraine
• Dizziness
• Somnolence (drowsiness)
• Fatigue
• Malaise
• Lethargy
• Asthenia (weakness)
• Fever
• Influenza-like symptoms
• Pain
• Thirst
• Dehydration
• Feeling abnormal
• Confusion
• Mental impairment
• Agitation
• Aggression
• Anxiety
• Depression
• Insomnia
• Irritability
• Nervousness
• Panic attack
• Personality change
• Cerebrovascular accident
• Transient ischemic attack (stroke caused by reduced blood flow to the brain)
• Lacunar infarction (a type of stroke caused by a block in a small blood vessel deep in the brain)
• Peripheral neuritis (nerve inflammation)
• Sensory-motor neuropathy (nerve damage)
• Guillain-Barre syndrome (a rare neurological disorder)
• Gait disturbance
• Balance disorder
• Foot drop
• Tremor
• Hemiparesis (muscle weakness on one side of the body)
• Hypoesthesia (reduced skin sensation)
• Paresthesia (abnormal skin sensation)
• Arthralgia (joint pain)
• Arthritis (joint inflammation)
• Joint stiffness and swelling
• Myopathy (muscle disease)
• Muscle spasm and twitching
• Muscle stiffness
• Myalgia (muscle pain)
• Muscle weakness
• Myotonia (difficulty in relaxing skeletal muscles after contraction)
• Hypotonia (decreased muscle tone)
• Rhabdomyolysis (breakdown of skeletal muscle cells)
• Elevated creatine phosphokinase (CPK)
• Precipitation of acute gouty arthritis
• Hypersensitive reactions such as:
  • Rash
  • Maculopapular rash (flat lesions with raised bumps)
  • Urticaria (hives)
  • Pruritus (itching)
  • Dermatitis
  • Dermographism (a skin condition that causes welts to develop with scratching or stroking the skin)
  • Eczema
  • Peeling skin
  • Photosensitivity
  • Purpura (purple spots on the skin caused by small blood vessels bursting)
  • Angioedema (swelling in the tissue under the skin or mucous membranes)
  • Drug rash with eosinophilia and systemic symptoms (DRESS)
  • Toxic epidermal necrolysis (a severe skin condition with widespread redness, skin cell death, and exfoliation which can lead to sepsis)
  • Stevens-Johnson syndrome (a rare medical emergency with flu-like symptoms and a painful rash)
• Anaphylaxis (severe allergic reaction)
• Alopecia (hair loss)
• Abnormal hair growth
• Hair color changes
• Flushing
• Hot flush and sweating
• Edema
• Electrolyte abnormalities
• Ecchymosis (bruising)
• Petechiae (skin discoloration)
• Skin lesion
• Abnormal skin odor
• Vascular damage
• Disseminated intravascular coagulation injury to cells in the renal, hepatic, circulatory, and central nervous systems
• Myelosuppression (bone marrow suppression)
• Blood disorders such as:
  • Neutropenia (low levels of neutrophil, a type of immune cell)
  • Increase or decrease in levels of leukocytes
  • Agranulocytosis (low granulocytes, immune cells with granules)
  • Anemia (low red blood cell count)
  • Aplastic anemia (anemia due to reduced red cell production)
  • Hemolytic anemia (anemia from rapid destruction of red cells)
  • Pancytopenia (decrease in all types of blood cells)
  • Eosinophilia (high level of eosinophils, a type of immune cells)
  • Thrombocytopenia (decrease in platelet count)
  • Idiopathic thrombocytopenic purpura (easy bruising and bleeding due to thrombocytopenia)
• Splenomegaly (spleen enlargement)
• Azoospermia (absence of sperm in semen)
• Oligospermia (low sperm count in semen)
• Decrease in libido
• Erectile dysfunction
• Gynecomastia (breast tissue growth in males)
• Breast pain
• Chest pain and discomfort
• Hypertension (high blood pressure)
• Hypotension (low blood pressure)
• Cardiac disorders such as:
  • Angina pectoris (chest pain due to coronary heart disease)
  • Atrial fibrillation/flutter
  • Cardiac murmur
  • Abnormal ECG
  • Palpitations
  • Sinus bradycardia (slow heartbeat)
  • Tachycardia (rapid heartbeat)
• Deafness
• Tinnitus (ringing in the ears)
• Vertigo
• Blurred vision
• Amblyopia (blurred vision)
• Cataracts
• Iritis (inflammation of the iris)
• Macular retinitis (inflammation in macula, the central portion of the retina)
• Altered taste
• Hyposmia (reduced sense of smell)
• Herpes zoster infection
• Abnormal blood and urine test results

Information contained herein is not intended to cover all possible side effects, precautions, warnings, drug interactions, allergic reactions, or adverse effects. Check with your doctor or pharmacist to make sure these drugs do not cause any harm when you take them along with other medicines. Never stop taking your medication and never change your dose or frequency without consulting your doctor.

Generic and brand names of antigout agents include:

• allopurinol
• Aloprim
• colchicine
• colchicine/probenecid
• Colcrys
• febuxostat
• Gloperba
• Mitigare
• Uloric
• Zyloprim