Asprin, The most famous analgesic.

Each drug have a family and friends, the family of asprin is called salicylates which are the chemical group, that contain salicylic acid as a part of its structure.

Aspirin is a weak organic acid (a cause of peptic ulcer) and is one of the oldest known drugs for the relief of fever and pain. Aspirin remains the standard to which most NSAIDs are compared
for efficacy.

Aspirin and related salicylates are rapidly absorbed upon oral administration,
with most absorption occurring in the small intestine. The pH of the stomach (a secondary site of drug absorption) along with the gastric emptying time of the
stomach (which depend on the food eaten), determines the rate of absorption of the drug (and so, the time till effect appears). Thus, food, which alters gastric emptying time and possibly the pH of the stomach, will alter absorption of the drug.

Salicylic acid is highly plasma protein bound, an effect that alters the pharmacokinetics of other drugs taken in combination with aspirin. Most of drugs bounds to the proteins in the plasma of our blood, this complex act as reservoir for the drug in the body, the drug is released from this binding at a specific rate, and exert its action on the body. So asprin if taken with another drug will increase the concentration of the free drug in blood and so may cause toxicity.

Salicylates passively diffuse to all tissues, including breast milk, fetal tissues, and the CNS.They tend to accumulate, since increases in dose decrease renal clearance and prolong the half-life of the drug. The higher the pH of the urine, the greater the clearance of the drug. So when some one intake a lot of asprin to suicide or by accident, we give him (under medical supervision) sodium bicarbonate (alkalinization of urine) as a step in the treatment to eliminate the drug out of the body.

Aspirin and related salicylates produce their pharmacological effects predominantly by inhibiting the synthesis of prostaglandins and to a lesser extent synthesis of the thromboxanes (role in platelet aggregation). The prostanoids are mediators of inflammatory responses in many cell types. COX-2 is induced during inflammation and is therefore considered to mediate most inflammatory responses. New enzyme must be synthesized to overcome the effects of aspirin, which in the case of platelets can take as long as 11 days.


Clinical Uses

Aspirin and related salicylates are the primary treatment for mild to moderate pain, such as that associated with headache, joint and muscle pain, and dysmenorrhea.

At higher doses aspirin is an effective analgesic in rheumatoid arthritis. The salicylates are also potent antipyretic agents, with the exception of diflunisal, which is only weakly active.
Other uses of aspirin include inhibition of platelet aggregation.

Overdose and Other Adverse Effects

The major consequence of aspirin overdose, Salicylate-induced stimulation of respiration leads to hyperventilation. In addition, increased carbon dioxide production and metabolic acidosis. The onset of acidosis, if not treated less than 1 hour after ingestion of aspirin, will lead to loss of rhythmicity of respiration and eventually loss of breathing.

Treatments include alkalinization of the urine, fluid replacement, gastric lavage with activated charcoal, dialysis, and artificial ventilation.

Some patients exhibit hypersensitivity to aspirin in the form of salicylism, which is accompanied by ringing in the ears (tinnitus), vertigo, and bronchospasm (especially in asthmatics). The use of salicylate-containing preparations is not the only source of this drug. Those sensitive to salicylates should be aware of salicylates in a number of foods, such as curry powder, licorice, prunes, raisins, and paprika.

The use of aspirin in children and teenagers with either chickenpox or influenza is contraindicated, since there is evidence linking the use of the salicylates in such diseases to Reye’s syndrome, a potentially fatal disease accompanied by liver damage and encephalopathy.

Other potential adverse effects of the drugs include the use of aspirin by patients who anticipate surgery or dental procedures. Such patients should be closely monitored and the salicylate stopped at least 1 week prior to surgery because of the possibility of increased clotting time and excessive bleeding. Similarly, the use of salicylates in pregnant women may increase bleeding upon delivery and prolong delivery. In addition, adverse fetal effects have been documented, such as low birth weight, fetal intracranial bleeding, and possible teratogenic effects.
Due to the ulcerogenic effects of the drugs, patients with a history of ulcers or other GI disturbances should be carefully monitored for increased blood in the feces while taking salicylates.

Drug Interactions

The salicylates displace a number of drugs from plasma protein binding sites.

Anticoagulants are potentiated by aspirin by:
(1) displacement of the anticoagulants from plasma proteins
(2) the intrinsic anticoagulant effect of aspirin.
Thus, the dosage of drugs such as coumarin and heparin should be reduced in patients taking aspirin.

Oral sulfonylureas (Orinase, DiaBeta):
for non–insulin-dependent diabetes or phenytoin (Dilantin) for seizures. Displacement of the sulfonylureas or phenytoin from plasma binding necessitates a decrease in dosage to prevent an acute hypoglycemic event or sedation, respectively.

Aspirin enhances the effects of insulin (leading to hypoglycemia), penicillins and sulfonamides (increasing acute toxicity), and corticosteroids.

Aspirin increases the hypotensive effects of the cardiac drug nitroglycerin but decreases the effectiveness of the loop diuretics.

In patients taking methotrexate for cancer chemotherapy, aspirin may increase retention of the drug, and severe toxicity may result.

Certain drugs modify the effectiveness or side effects of aspirin.

Phenobarbital, occasionally used for seizures, induces liver enzymes that increase the
metabolism and excretion of aspirin,

Adrenoceptor– blocking drugs, such as propranolol, and decrease the anti-inflammatory effects of aspirin, whereas reserpine decreases its analgesic effects.

Antacids decrease the absorption of aspirin. Alcohol consumption in combination with aspirin increases the latter’s ulcerogenic effects.


ِAs i always say, don't consider any drug as a candy, but it is a toxin, which we use in a small dose.
Aspirin is OTC (over the counter) but it is still a drug (toxin) so be careful during the use of it.