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Oral Antigout Drugs
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Gout
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Gout is a type of arthritis where uric acid crystals (monosodium urate) deposit within and around the joints. Uric acid is a metabolic waste made from metabolism of purines (found in many foods and in human tissue) and primarily excreted from the body via the kidneys. An elevated level of uric acid in the blood is known as hyperuricemia. When the body either overproduces uric acid or under-excretes it through the kidneys, excess uric acid can accumulate, leading to the formation of needle-like crystals in the joints that trigger acute gout attacks.
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The most common symptom of gout is a sudden, severe onset of joint pain accompanied by significant swelling, warmth, and redness. The large joint of the big toe is typically affected, although gout could affect almost any joints and can occur in more than one joint concurrently. Joints located toward the extremities are most susceptible, including the midfoot (the area where your shoelaces would sit), ankles, knees, fingers, elbows and wrists.
Men are more likely to develop gout than pre-menopausal women. This disparity exists because female sex hormones help enhance the urinary excretion of uric acid. Key risk factors for developing gout include: advancing age, excessive consumption of alcohol or purine-rich foods (e.g. offal, shellfish, liver), overweight and obesity, etc. Sometimes, gout may also be caused by certain chronic diseases, such as high blood pressure, diabetes mellitus, or moderate to severe kidney disease.
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Classes of Oral Antigout Drugs* |
Oral antigout drugs are categorized into two primary groups: drugs to relieve symptoms of gout attacks and drugs to prevent future gout attacks.
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Drugs to relieve symptoms of gout attacks:
- Non-steroidal anti-inflammatory drugs (NSAIDs): These drugs inhibit inflammation to provide pain relief during a gout attack. Common examples include ibuprofen, naproxen, diclofenac and indomethacin. For more information on NSAIDs, please refer to https://www.drugoffice.gov.hk/eps/do/en/consumer/news_informations/dm_03.html
- Colchicine: It is used for the reduction of pain and swelling associated with acute gout flares.
- Corticosteroids: Corticosteroids offer relief from the severe pain and inflammation of a gout attack. They are typically used as a second-line alternative for patients who cannot tolerate or have contraindications to NSAIDs or colchicine. Examples include prednisone and prednisolone.
For more information on oral corticosteroids, please refer to https://www.drugoffice.gov.hk/eps/do/en/consumer/news_informations/dm_02.html
Drugs to prevent future gout attacks:
- Xanthine oxidase inhibitors: These drugs reduce the body’s internal production of uric acid by inhibiting the xanthine oxidase enzyme. Examples include allopurinol and febuxostat.
- Uricosuric drugs: These drugs lower serum uric acid concentrations by actively increasing the elimination of uric acid through the kidneys. Examples include probenecid and benzbromarone.
- Colchicine: It may be used as a short-term prophylactic measure to prevent gout attacks when a patient is initially starting uric acid-lowering therapies (such as allopurinol and uricosuric drugs).
In Hong Kong, almost all antigout drugs are prescription-only medicines, and therefore they should be administered strictly under a doctor’s supervision.
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Common Side Effects and Precautions
Antigout drugs*
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Common side effects*
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Precautions*
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Drugs to relieve symptoms of gout attacks |
| 1. | NSAIDs (e.g. ibuprofen, naproxen, diclofenac) |
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- Nausea
- Vomiting
- Diarrhoea
- Constipation
- Decreased appetite
- Fluid retention
- Gastrointestinal (GI) disturbance
- Hypersensitivity reactions
- Headache
- Dizziness
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- Should be used with caution in elderly, in patients with cardiac impairment, asthma, and coagulation defects
- Should not be used in patients with a history of hypersensitivity to aspirin or any other NSAID, active gastrointestinal ulceration or bleeding and severe heart failure
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| 2. Colchicine |
- Nausea
- Vomiting
- Diarrhoea
- Abdominal pain
- Rash
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- Should be used with caution in elderly, in patients with cardiac, hepatic, renal, or gastrointestinal disease
- Should not be used in patients with blood disorders
- Do not exceed the dose as prescribed by your doctor because of the narrow therapeutic range of colchicine
- Stop taking colchicine if vomiting or diarrhoea occurs
- Avoid grapefruit or grapefruit juice
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| 3. | Corticosteroids (e.g. prednisone and prednisolone) |
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- Weight gain
- Osteoporosis
- Increased risk of infection
- Muscle weakness
- Rapid mood swings
- Gastrointestinal discomfort
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- Should be used with caution in elderly, in patients with congestive heart failure, recent myocardial infarction, hypertension, diabetes mellitus, epilepsy, glaucoma, hypothyroidism, hepatic failure, osteoporosis, peptic ulceration, psychoses or severe affective disorders, and renal impairment
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Drugs to prevent future gout attacks |
| 4. | Xanthine oxidase inhibitors (e.g. allopurinol and febuxostat) |
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- Rash
- Gastrointestinal disturbance
- Headache
- Diarrhoea
- Dizziness
- Malaise
- Liver function abnormalities (for febuxostat)
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- Adequate fluid intake (2–3 litres/day) is necessary (for allopurinol)
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| 5. | Uricosuric drugs (e.g. probenecid and benzbromarone) |
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- Gastrointestinal disturbance
- Diarrhoea
- Nausea and vomiting
- Headache
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- Adequate fluid intake (2–3 litres/day) is necessary
- Should not be used in patients with a history of uric acid renal calculi
- Should be used with caution in patients with a history of peptic ulceration (for probenecid)
- Severe hepatic lesions have been associated with the use of benzbromarone. Patients who have hepatic disorders should avoid taking this drug
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- Nausea
- Vomiting
- Diarrhoea
- Abdominal pain
- Rash
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- Should be used with caution in elderly, in patients with cardiac, hepatic, renal, or gastrointestinal disease
- Should not be used in patients with blood disorders
- Do not exceed the dose as prescribed by your doctor because of the narrow therapeutic range of colchicine
- Stop taking colchicine if vomiting or diarrhoea occurs
- Avoid grapefruit or grapefruit juice
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General Advice*
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- Rest and elevate the affected limb to help minimize swelling. Applying an ice pack wrapped in a towel to the affected joint for no more than 20 minutes at a time can also provide localized pain relief.
- Be fully aware of the name and dosage of the drugs you are prescribed. Maintain a cautious awareness of their potential side effects.
- Strictly limit or avoid the intake of purine-rich foods, including offal (such as liver, kidney, heart), certain seafoods (such as mussels, scallops, sardines), and excessive portions of red meat.
- Avoid alcoholic beverages and sugar-sweetened drinks.
- Strive to maintain an optimal body weight and engage in regular physical exercise.
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Communication with Your Doctor*
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- Consult your doctor promptly if you experience a sudden and intense onset of joint pain.
- Seek immediate medical attention if you develop a fever alongside severe, worsening joint pain and swelling.
- It is important to consult your doctor to determine the best treatment option. Your doctor will prescribe the most appropriate medications based on your clinical condition and response to treatment.
- Inform your doctor if you are pregnant, planning to become pregnant or are currently breastfeeding.
- Seek medical advice as soon as possible if you experience any unusual symptoms or suspected side effects related to your antigout drugs.
- Attend regular medical follow-up appointments as advised by your doctor.
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Storage Guidelines
Oral antigout drugs should be stored in a cool dry place. Do not refrigerate unless specified. Always keep medications out of reach and sight of children to prevent accidental ingestion.
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* This information may not cover all possible side effects, precautions, or medical advice. Always consult your healthcare professional for guidance.
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Acknowledgement: The Drug Office would like to thank the Professional Development and Quality Assurance Service (PD&QA) for their valuable contribution to the preparation of this article.
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