Febuxostat vs. Allopurinol - Two Common Very Common Prescriptions For Gout and How They Work

Gout is a form of inflammatory arthritis that is caused by hyperuricaemia or high amounts of uric acid in the blood. When in accumulated amounts, uric acid tends to form monosodium urate crystals that localize around the joints and periarticular tissue, causing an inflammatory response and in the long term, tissue damage. Initial treatment for gout includes making necessary diet and lifestyle changes to help establish good habits that would otherwise be contributing factors to elevated uric acid levels. For some individuals however – especially those who suffer from a genetic hyperuricaemia condition find difficulty when it comes to lowering their uric acid levels. In these instances, a rheumatologist will prescribe medications to help with the inhibition of uric acid creation. Febuxostat and Allopurinol are two of the more commonly prescribed medications today, and both work differently chemically and individually. It’s important to understand how each works to determine what might be best for you.

Inhibiting Uric Acid Creation

When purines enter the body (usually found in certain foods that we eat) it relies on the enzyme Xanthine Oxidase (XO) to break down the purine to uric acid. Febuxostat and Allopurinol are designed to directly affect the enzyme Xanthine Oxidase, and both medications work differently. When Allopurinol is synthesized by the body, it takes on a similar structure to purines and is broken down by the XO enzyme. Essentially, what Allopurinol does is act as a doppelganger so that the XO enzyme can focus on the imposter purine, instead of the real one, thus preventing the creation of uric acid. Not only does Allopurinol work during purine metabolism, but also during pyrimidine metabolism as well, meaning it gets the XO’s enzyme attention in two stages instead of just one. Febuxostat on the other hand only acts as a non-purine inhibitor of Xanthine Oxidase, meaning it simply pushes the XO enzyme away from the purine compounds, but doesn’t necessarily distract them like Allopurinol does. Febuxostat also only focuses on the Xanthase Oxidase enzyme, whereas Allopurinol has an effect on different enzymes.

Other influences

In addition to acting as a purine doppelganger, Allopurinol also reduces the enzyme XO to the point where it essentially commits ‘suicide’. This means that once the Allopurinol leaves you system, there are no enzymes to metabolize the purines in your body and create uric acid. Febuxostat on the other hand, acts as a very potent inhibitor on both the reduced the oxidized forms of the enzyme.

Prescriptions & Dosage

Allopurinol is the most widely and commonly prescribed urate-lowering medication for most gout patients. When prescribed, doctors will initiate patients on a low dose and gradually increase the amount based on the patients’ reaction, results and needs. Unfortunately, for reasons that are unclear, the gradual increase in dosage rarely happens and most patients end up sticking with the original dosage they were prescribed which in some cases may not be strong enough. If you take Allopurinol, it’s important to follow up with your doctor on your progress to determine if you need to raise your dosage.

Febuxostat is usually administered as an oral dose of 300 mg and has been shown to be effective without much need for an increase in dosage. This means that it is significantly more effective upon initial treatment or dosage at reducing uric acid levels.

Other considerations

Speak with your doctor prior to drug administration about potential side effects or drug interactions (if you are on any other medications) before settling on a uric acid lowering drug. It’s important to know if you might have any allergic reactions or if any of the side effects might affect your job or daily performance. Your doctor will be able to provide you with the best advice when it comes to choosing the drug that is right for you.