Uric acid is a substance that normally forms when the body breaks down waste products (called purines).
Uric acid is usually dissolved in the blood and passes through the kidneys into the urine.
For people with gout , the uric acid level in the blood is so high that uric acid crystals form and deposit in joints and other tissues. This causes the joint lining to become inflamed, resulting in sudden and severe attacks of pain, tenderness, redness and warmth.
Using medications for gout can be complicated, because the treatment needs to be tailored for each person and may need to be changed from time to time.
To relieve the pain and swelling of an acute attack, the doctor may prescribe nonsteroidal anti-inflammatory drugs (NSAIDs), colchicine, corticosteroid drugs, and/or adrenocorticotropic hormone (ACTH).
colchicine also inhibits neutrophil motility and activity, leading to a net anti-inflammatory effect.
Colchicine also inhibits uric acid ( urate ) crystal deposition, which is enhanced by a low pH in the tissues, probably by inhibiting oxidation of glucose and subsequent lactic acid production in leukocytes.
The inhibition of uric acid crystals is a vital aspect on the mechanism of gout treatment.
Long term (prophylactic) regimens of oral colchicine are absolutely contraindicated in patients with advanced renal failure (including those on dialysis).
10-20% of a colchicine dose is excreted unchanged by the kidneys.
Colchicine is not removed by hemodialysis.
Cumulative toxicity is a high probability in this clinical setting. A severe neuromyopathy may result. The presentation includes a progressive onset of proximal weakness, elevated creatine kinase, and sensorimotor polyneuropathy.
Colchicine poisoning has been compared to arsenic poisoning: symptoms start 2 to 5 hours after the toxic dose has been ingested and include burning in the mouth and throat, fever , vomiting , diarrhea , abdominal pain and kidney failure .
These symptoms may set in as many as 24 hours after the exposure. Onset of multiple-system organ failure may occur within 24 to 72 hours. This includes hypovolemic shock due to extreme vascular damage and fluid loss through the GI tract , which may result in death.
Additionally, sufferers may experience kidney damage resulting in low urine output and bloody urine; low white blood cell counts (persisting for several days); anemia ; muscular weakness; and respiratory failure .
Recovery may begin within 6 to 8 days. There is no specific antidote for colchicine, although various treatments do exist