1 What is Amigesic?

Brand: Amigesic, Azulfidine, Azulfidine Entabs, Bayer, Canasa, Colazal, Dipentum, Doans Extra Strength, Doans Regular, Dolobid, Ecotrin, Giazo, Kaopectate, Pepto Bismol, Salflex, Tricosal, Trilisate

Generic: Aspirin

Amigesic is acetylsalicylic acid. It is rapidly converted in the body to Salicylic acid which is responsible for most of the actions. It is one of the oldest analgesics associated with anti-inflammatory effect and is still widely used.

It also possesses antipyretic action. It is commonly prescribed in low doses by the doctors to lessen the risk of myocardial infarction or stroke because of its anti-platelet action.

It is well absorbed from stomach and upper gastrointestinal tract.

In order to relieve mild to moderate non-visceral pain (e.g. headache, myalgia), it is preferably indicated. Moreover, it is also prescribed in those patients who are suffering from acute rheumatic fever, rheumatoid arthritis, and arterial thromboembolism.

2 What To Know Before Using

If you are about to start Amigesic, the risk and benefit ratio of taking this medication should be considered. This is a decision that your doctor will make with your active participation.

Certain factors that should be considered are:

  • present and past illness, drug interactions, hypersensitivity reactions, pregnancy, lactation, metabolic impairments etc. as they may alter the drug action.

Aspirin may be used for a variety of purposes because of its broad pharmacological actions. At the same time, it may acts as an analgesic, antipyretic and anti-inflammatory drug. Although it effectively relieves inflammatory, tissue injury related, connective tissue and integumental pain, it is relatively ineffective in severe visceral and ischaemic pain.

The analgesic action is mainly due to obtunding of peripheral pain receptors and prevention of prostaglandin-mediated sensitization of nerve endings. A central subcortical action raising threshold to pain perception also contributes, but the morphine-like action on psychic processing or reaction component of the pain is missing. Thus, it is a weaker analgesic than morphine type drugs.

On the contrary, there is less chance of sedation, subjective effects, tolerance or physical dependence. 

3 Proper Usage

Medicines should be used following the directions given by a doctor. The dose of Amigesic will vary according to patient’s condition or requirements. You should follow the doctor's directions and advice.

The amount of medicine that you take should not exceed the maximum therapeutic dose. Also, the frequency of your daily drug administration and the duration of drug therapy depend on the particular medical problem for which you are taking the medicine.

  • Usage of aspirin as analgesic: for headache (including mild migraine), backache, myalgia, joint pain, pulled muscle, toothache, neuralgias and dysmenorrhea. It is effective in low doses (0.3-0.6 g 6-8 hourly). Analgesic effect is maximal at ~ 1000 mg (single dose).
  • Usage as antipyretic: it is effective in fever of any origin. The dose is same as for analgesia. 
  • Acute rheumatic fever: aspirin is the first drug to be used in all cases. Other drugs are added or substituted only when it fails or in severe cases (corticosteroids act faster). In a dose of 4-5 g or 75-100 mg/kg/day (in divided portions producing steady state serum salicylate concentration 15-30 mg/dl) it brings about marked symptomatic relief in 1-3 days. Dose reduction may be started after 4-7 days and maintenance doses (50 mg/kg/day) are continued for 2-3 weeks or till signs of active disease (raised ESR) persist. 
  • Rheumatoid arthritis: aspirin in a dose of 3-5 g/day is effective in most cases; produces relief of pain, swelling and morning stiffness, but progress of the disease process is not affected. Since large doses of aspirin are poorly tolerated for long periods, it is rarely used now; other NSAIDs are preferred.
  • Osteoarthritis: it affords symptomatic relief only and may be used on ‘as and when required’ basis.
  • Postmyocardial infarction and poststroke patients: by inhibiting platelet aggregation aspirin lowers the incidence of reinfarction.  Large studies have demonstrated that aspirin 60-100 mg/day reduces the incidence of myocardial infarction (MI). It is now routinely prescribed to post-infarct patients and for primary prophylaxis as well. 
  • Other uses of aspirin: pregnancy induced hypertension and pre-eclampsia, patent ductus areteriosus, familial colonic polyposis, prevention of colon cancer etc. often require aspirin administration.

4 Precautions To Take

Some important guidelines are given below which should be maintained before you start receiving Amigesic or other salicylates:

  • Aspirin is contraindicated in patients who are sensitive to it and in peptic ulcer, bleeding tendencies, in children suffering from chicken pox or influenza. Due to risk of Reye’s syndrome, pediatric formulations of aspirin are prohibited in the UK.
  • It should be avoided in diabetics, in those with low cardiac reserve or frank congestive heart failure (CHF) and in juvenile rheumatoid arthritis.
  • Aspirin should be stopped 1 week before elective surgery.
  • Given during pregnancy, it may be responsible for low birth weight babies. Delayed or prolonged labour, greater postpartum blood loss and premature closure of ductus arteriosus may occur if aspirin is taken at or near term.
  • It should be avoided by breastfeeding mothers.
  • Avoid high doses in G6PD deficient individuals – haemolysis can occur.
  • Cases of hepatic necrosis have been reported. Thus, aspirin should not be used in chronic liver disease.

Certain drugs should not be used concurrently with such medications. It is always recommended to consult with your doctor if you are in need of some drugs for another health problem. Sometimes, it is must to avoid some particular medicines during this drug therapy in order to get rid of serious drug reactions.

Some important drug reaction are given below:

  • Aspirin displaces warfarin, naproxen, sulfonylureas, phenytoin and methotrexate from binding sites on plasma proteins: toxicity of these drugs may occur. Its antiplatelet action increases the risk of bleeding in patients on oral anticoagulants.
  • It inhibits tubular secretion of uric acid (at analgesic doses) and antagonizes uricosuric actions of probenecid.
  • Aspirin blunts diuretic action of furosemide and thiazides and reduces potassium conserving action of spironolactone. Competition between canrenone (active metabolite of spironolactone) and aspirin for active transport in proximal tubules has been demonstrated.
  • Aspirin reduces protein bound iodine levels by displacement of thyroxine; but hypothyroidism does not occur. 

5 Potential Side Effects

There are some unwanted side-effects associated with Amigesic that usually do not need medical attention. These side-effects usually go away during the treatment episode as your body adjusts to the medicine. Additionally, your health care professional may advise you about the ways to prevent or reduce those unwanted side-effects.

Sometimes you may need to consult with the doctor if you feel any of these: 

  • Side effects that occur at analgesic dose (0.3-1.5 g/day) are nausea, vomiting, upper abdominal discomfort, peplic ulceration, gastric mucosal damage, increased occult blood loss in stools etc. 
  • Hypersensitivity reactions and idiosyncrasy may occur infrequently which include rashes, fixed drug eruption, urticarial, rhinorrhea, angioedema, asthma and anaphylactoid reaction. 
  • Anti-inflammatory doses (3-5 g/day): produce the syndrome called salycylism which is characterized by dizziness, tinnitus, vertigo, reversible impairment of hearing and vision, excitement and mental confusion, hyperventilation and electrolyte imbalance. 
  • Aspirin therapy in children with rheumatoid arthritis has been found to raise serum transaminases, indicating liver damage. Most cases are asymptomatic, but it is potentially dangerous. 
  • Acute salicylate poisoning: it is more common in children. Its manifestations are vomiting, dehydration, electrolyte imbalance, acidotic breathing, hyper or hypoglycemia, petechial hemorrhages, restlessness, delirium, hallucinations, hyperpyrexia, convulsions, coma and death due to respiratory failure and cardiovascular collapse. Serious toxicity is seen at serum salicylate levels >50 mg/dl.

Fatal dose of aspirin in adults is estimated to be 15-30 g, but is considerably lower in children.