FDA questioned the use of aspirin to prevent first heart attack


Editors:

Elham Reshid and Hailemariam Shimelis

Aspirin is a salicylate and non-steroidal anti-inflammatory drug (NSAID) which works by reducing substances in the body that cause pain, fever, and inflammation. Given that aspirin inhibits the function of platelets for prolonged periods, it is also used for reducing the risk of stroke and heart attack.

Since the 1990s, clinical data have shown that in people who have experienced a heart attack or, stroke or who have a disease of blood vessels in the heart, a daily low dose of aspirin can help to prevent recurrence. The American Heart Association also recommends that “people at high risk of heart attack should take a daily low dose of aspirin if told to do so by their health-care provider.

A low-dose tablet contains 80 milligrams (mg) of aspirin, compared with 325 mg in a regular strength tablet.However, consumers and patients who do not suffer from cardiovascular disease sometimes consider taking aspirin to reduce the possibility of having a heart attack or stroke, according to the FDA report and this was defined as primary prevention. Such aspirin therapy reduces the clumping action of the blood’s clotting cells, called platelets, and may prevent a heart attack, according to experts. However, experts also warn that there may be serious side effects from daily use of aspirin, including internal bleeding.

Along with this, FDA recently denied a request submitted by Bayer HealthCare, LLC, requesting a change in the prescribing information for health care professionals (professional labeling) for aspirin to allow marketing of the product for prevention of heart attacks in patients with no prior history of cardiovascular disease. The FDA has reviewed the available data and does not believe the evidence supports the general use of aspirin for primary prevention of a heart attack or stroke. In fact, there are serious risks associated with the use of aspirin in situations where the benefit of aspirin for primary prevention has not been established and this included increased risk of bleeding in the stomach and brain.

Nevertheless, the available evidence supports the use of aspirin for preventing another heart attack or stroke in patients who have already had a heart attack or stroke, or has other evidence of coronary artery disease. In patients who have had such cardiovascular events, the known benefit of aspirin for secondary prevention outweighs the risk of bleeding.

Now, FDA has already questioned the value of taking aspirin to try to ward off a first heart attack or stroke and is currently awaiting results of additional clinical trials that are underway and are expected to have reportable results in the next few years. These clinical trials may provide new evidence that could be the basis for changing the current uses (indications) for aspirin.

click for pdf here.

References:

http://www.fda.gov/Drugs/ResourcesForYou/Consumers/ucm390574.htm 

http://www.foxnews.com/health/2014/05/05/fda-questions-use-aspirin-to-prevent-first-heart-attack/ 

http://www.webmd.com/heart-disease/news/20140506/daily-aspirin-regimen-not-safe-for-everyone-fda-warns 

http://www.medicinenet.com/aspirin-oral/page2.htm

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Drug Alert on Common IV Fluids


Editors:

Elham Reshid and Hailemariam Shimelis

The administration of intravenous (IV) fluids is one of the most  common and universal interventions in medicine. However, the choice of IV flids has remained one of the most controversial subjects in critical care over the past half a century.

IV fluids are divided into plasma expanders (Colloids) and Crystalloids. Colloids are solutions that contain large molecules, which do not pass cell membrane. When infused, they remain in the intravascular compartment and expand its volume by drawing fluid from the extracellular space due to their high oncotic pressure. Crystalloids are solutions containing small molecules that easily flow across cell membranes and increase fluid volume in both interstitial and intravascular spaces.

It is recommended that the initial resuscitating fluid should be either Normal Saline (NS) (0.9% sodium chloride) or Ringer’s lactate (RL) (also called Hartmann’s solution) which are both crystalloids. Alternatives are the so-called collioids which constitute macro-sugar based solutes dissolved in saline with other electrolytes

(Dextrose in normal saline (DNS)) and it is usually given as maintenance dose after initial crystalloid infusion. Dextrose in water (DW) is also widely used as a maintenance fluid.

The most commonly used IV fluids are discussed below with their indications and contraindications.

NS and RL

  • Both are used for volume resuscitation unlike colloids
  • NS is just sodium chloride in water while RL has potassium chloride, sodium lactate and calcium in addition to sodium chloride
  • Due to the lactate ion, RL is also used for alkalinization of urine in addition to fluid and electrolyte balance
  • NS is the safest of all to be infused when other IV medication are also given and it is the only fluid used with administration of blood products
  • NS is the fluid of choice for resuscitation efforts
  • RL is also a first line fluid for resuscitation in certain patients such as those with burn injury
  •  RL should never be given simultaneously with blood through the same administration set as the calcium will bind to the citrate
  • NS is contraindicated in hypertension, pulmonary edema and high sodium levels in the body
  • RL should not be used in people with lactic acidosis (but used for metabolic acidosis), kidney failure (as it contains potassium), and liver disease (as they cannot metabolize lactate into bicarbonate)
  • LR should not be given to patients whose pH is
    greater than 7.5

DW and DNS

  • DW is 5% glucose in water while DNS constitutes sodium chloride in addition to the 5% sugar
  • Both are used for maintenance therapy after fluid resuscitation and are not used as volume expander
  • Both are used in small amounts to correct “free water defiits” when it is needed to bring down a patient’s high sodium level
  • Both are sources of calories on top of fluid and electrolyte replacement and are recommended in situation where glucose is needed
  • Both should not be administered simultaneously with blood through the same administration set as they hemolyze blood
  • Not used in the early postoperative period, as the body’s reaction to the surgical stress could lead to an increase in antidiuretic hormone (vasopressin)
  • Patients at risk for intracranial pressure should not recieve DW, as it increases cerebral edema
  • DNS should be used with great care in patients with congestive heart failure, severe renal insufficiency, and in clinical states where edema exists with sodium retention
  • Special precautions should be taken in diabetic patients taking both IV fluids and are contraindicated in diabetic coma while patient is hyperglycemic

References:

http://www.steinergraphics.com/surgical/005_13.4.html
http://www.rxlist.com
http://www.openanesthesia.org/Fluid_Resuscitation
http://www.merckmanuals.com