Anesthetics and Gout Flashcards
What is a local anesthetic?
An agent that interrupts pain impulses in a specific region of the body without a loss of patient consciousness. Renders a specific portion of the body insensitive to pain
Normally completely reversible
What drugs are local anesthetics?
Na channel blockers
Lidocaine, novocaine, cocaine
What is the difference between an anesthetic and an analgesic?
Anesthetics block Na channels, thus blocking ALL nerve transmission
Analgesics only inhibit pain
What are anesthetics often given with?
Opioids to increase effectiveness and epinephrine to prolong the effect (inhibits blood flow)
How is surface anesthesia accomplished?
By application of a local anesthetic to the skin or mucous membranes
What is surface anesthesia used for?
To relieve itching, burning and surface pain (minor sunburn)
Prior to injection
How does a nerve block work?
A local anesthetic is injected around a nerve that leads to the operative site (any nerve that is not spinal)
More concentrated forms of anesthesia are used
What is spinal anesthesia (epidural)?
Local anesthetic is injected into the subarachnoid space of the spinal cord
Blocks everything in the lower body
What are the effects of anesthetic?
First autonomic activity is lost, then pain and other sensory function. Motor is last to be lost. Peripheral is lost first
When wearing off, reverse is restored (motor first)
What is infiltration anesthesia used for?
Minor surgical and dental procedures
What is infiltration anesthesia?
Injection of the anesthetic solution intradermally, subcutaneously or submucosally across the path of nerves supply the target area
May be given in circular pattern around operative area
What is nerve block anesthesia used for?
Surgical, dental and diagnostic procedures
Therapeutic management of pain
Do side effects usually occur with anesthetics?
No as they are only used locally
How would side effects occur with anesthetics?
Inadvertent intravascular injection
Excessive dose or rate of injection
Slow metabolic breakdown
Injection into a highly vascular tissue (into the blood is bad)
What is gout?
Accumulation of uric acid crystals in joints causing acute joint inflammation (gouty arthritis)
What is gout associated with?
Ingestion of red meat, cheese and wine (large intake of purines)
“Rich man’s disease”
Who is gout most common in?
Asians
Why does the uric acid build up in the joints?
Because there is a high concentration of uric acid all throughout the body, the different pH found in the joints will cause the uric acid to come out of solution as crystals
What is the important enzyme in uric acid production?
Xanthine oxidase
Converts hypoxanthine to xanthine and that to uric acid
What is colchicine?
A weak anti inflammatory agent that is not analgesic or antipyretic
How does colchicine work?
Impairs PMN motility and chemotaxis and thus inflammatory response
No effect on plasma or urinary uric acid
What could we also use colchicine for?
Low dose continuous prophylactic therapy
What are some symptoms of colchicine toxicity?
Nausea, vomiting, diarrhea, abdominal cramping, may cause death
What is allopurinol?
A xanthine oxidase inhibitor that reduces urate formation but leaves hypoxanthine sitting (risk of hypoxanthine stones)
Active metabolite
What should allopurinol be cautioned in?
Fluid intake and acute attack of gout
What is allopurinol used for?
Prophylaxis when acute gouty attacks happen frequently
Which NSAID is the drug of choice for gout?
Indomethacin
What may be the genetic predisposition for gout?
Reabsorbing too much uric acid
What makes indomethacin good for gout?
Less toxic than cochicine with long term use
Not uricosuric
Afford symptomatic relief
What are the side effects of indomethacin?
GI side effects
What does probenecid do?
Stops the reabsorption of uric acid (uricosuric)
Half-life dose dependent
Highly protein bound
What are the downsides of probenecid?
Inhibits the excretion of other acidic drugs
Caution with renal urate stones (fluid intake)
