**Question:** Which of the following increases uric acid excretion?

A. Allopurinol
B. Colchicine
C. Colchicine and Allopurinol together
D. Colchicine and Allopurinol together

**Correct Answer:** C. Colchicine and Allopurinol together

**Core Concept:**
Uric acid is a waste product produced during the breakdown of purines in the body. Normal levels of uric acid are maintained through a balance between production and excretion. The kidneys play a crucial role in excreting uric acid through urine.

**Why the Correct Answer is Right:**
Allopurinol is a medication primarily used to lower uric acid levels in patients with hyperuricemia or gout. When given alone, allopurinol primarily reduces uric acid production by inhibiting the enzyme xanthine oxidase, which catalyzes the final step in purine degradation.

Colchicine, on the other hand, is a medication used in the treatment of gout and familial Mediterranean fever. It inhibits the recruitment of neutrophils to the site of inflammation, thereby reducing inflammation and joint pain. However, colchicine alone does not directly affect uric acid levels.

Combining allopurinol and colchicine significantly enhances the reduction of uric acid levels. This is due to the complementary mechanisms of action of both drugs. Allopurinol reduces uric acid production, while colchicine reduces inflammation, which is a risk factor for hyperuricemia. By combining these drugs, they work together to lower uric acid levels effectively.

**Why Each Wrong Option is Incorrect:**
A. Allopurinol alone is effective in lowering uric acid levels but does not directly affect uric acid excretion.
B. Colchicine alone does not significantly impact uric acid levels, making it an incorrect choice.

**Colchicine and Allopurinol together:** Although colchicine and allopurinol have complementary effects, their mechanisms do not directly target uric acid excretion. Therefore, option D is also incorrect.

**Colchicine and Allopurinol together:** By combining allopurinol and colchicine, we achieve a synergistic effect in lowering uric acid levels, as they work together to reduce inflammation and inhibit purine synthesis, which contributes to hyperuricemia. This makes option C the correct answer.

**Core Clinical Pearls:**
In patients with gout or hyperuricemia, combining allopurinol and colchicine can be beneficial for reducing uric acid levels and inflammation, respectively. However, it is essential to consider potential side effects and drug interactions when prescribing these medications. Always consult with a physician before initiating any combination therapy.