6.9 Antigout

Gout is a chronic inflammatory arthritis characterized by episodes of severe joint pain, typically in the great toe. Hyperuricemia (high blood levels of uric acid) is defined as serum levels above 7mg/dL in men and 6 mg/dL in women (Rosenjack Burchum & Rosenthal, 2019). Men are more likely to get gout than women. It is due to either an excess production of uric acid or impaired renal excretion of uric acid.  The deposit of sodium urate (sodium salt of uric acid) in the synovial joint precipitates a series of events leading to inflammation, deposition of large, gritty deposits called tophi in the joint and also in the kidney leading to renal damage. The cause of gout is multifactorial, including a genetic predisposition, dietary influences (purine rich diet, alcohol) and health conditions such as obesity, hypertension and diabetes.

Two different classes of medications are used to treat gout. The first involves short term relieve of symptoms such as non-steroidal anti-inflammatories, such as Indomethacin or COX-2 inhibitor, Celebrex.  If NSAIDs are not decreasing the inflammation, corticosteroids may be ordered.

The second part of treatment is for prevention or management of chronic gout by lowering serum uric acid levels. Allopurinol is widely used. Other medications include Colchicine (anti-inflammatory by limited leukocyte infiltration) for acute flare-ups and prophylaxis during the initiation of urate-lowering therapy.  Probenecid may also be ordered to increase uric acid excretion.

Xanthine Oxidase Inhibitor: Allopurinol

Indications for Use

Allopurinol is used for the prevention and treatment of gouty arthritis and nephropathy and for the treatment of secondary hyperuricemia.

Mechanism of Action

Allopurinol blocks the production of uric acid by inhibiting the action of xanthine oxidase (Vallerand & Sanoski, 2024). This reduction in uric acid production inhibits phagocyte infiltration inside the synovial cavity. This then prevents new tophus formation and allopurinol can also regress tophi that have already formed. It also prevents nephropathy or urate nephrolithiasis.

Nursing Considerations

Allopurinol is safe for all ages. It is well tolerated and absorbed well after oral administration. It should be taken after meals to avoid GI upset. It is also important to ensure the client is well-hydrated, with the potential of 3000 mls of water a day, to avoid renal calculi.

The drug must be taken consistently to have any long-term benefit.

For clients with renal impairment, the dose will be reduced.

Initial therapy: may precipitate a gouty attack. If this occurs, take colchicine or NSAIDs.

Monitoring: clients should return for bloodwork every 2-5 weeks while titrating the dose to achieve a target serum uric acid level.  Follow up labs are every 6 months (Qurie, Preuss & Musa, 2023).

Adverse/Side Effects

Allopurinol is well tolerated. Common side effects include nausea, diarrhea and abdominal discomfort.  A maculopapular pruritic rash can also occur.

CNS effects include drowsiness, headache or a metallic taste.

Hypersensitivity syndrome or DRESS syndrome – this is characterized by a rash, fever, eosinophilia, and eventual liver and renal dysfunction (Cleveland Clinic, 2017).

Client Teaching

• Advice clients to take as directed. Take after meals.
• Ensure to stay hydrated, drink 3000 mls of water a day to avoid renal calculi.
• Alkaline diet: eat more alkaline-rich foods, such as plant-based proteins, low-fat diary, certain fruits (cherries, citrus), most vegetables and molasses. This will decrease the chance of stone formation.
• Reduce eating purine-rich foods such as meat, seafood and alcohol. These may contribute to uric acid production.
• Report any rash or unusual bleeding.

Allopurinol Medication Card

Now let’s take a closer look at the medication card for allopurinol. Medication cards like this are intended to assist students to learn key points about each medication. Because information about medication is constantly changing, nurses should always consult evidence-based resources to review current recommendations before administering specific medication. Basic information related to each class of medication is outlined below (Rosenjack Burchum & Rosenthal, 2019; Vallerand, A., & Sanoski, 2024)

Downloadable file (.docx):  Allopurinol Medication Card CH6.9BySheila

References

Adams, M., Urban, C., El-Hussein, M., Osuji, J. & King, S. (2018). Pharmacology for Nurses. A pathophysiological approach (2nd Canadian ed.). Pearson Canada Inc: Ontario

Cleveland Clinic. (2017, January 26). Acute v. chronic pain. https://my.clevelandclinic.org/health/articles/12051-acute-vs-chronic-pain. ↵

Rosenbach Burchum, J., & Rosenthal, L. (2023). Lehne’s pharmacology for nursing care (11th ed.). Saunders

Qurie, A., Preuss, C. & Musa, R. (2023). Allopurinol. National Library of Medicine. StatPearls. Allopurinol – StatPearls – NCBI Bookshelf

Vallerand, A., & Sanoski, C. A. (2024). Davis’s Drug Guide for Nurses (19th ed.). F.A. Davis Company.