Acetylsalicylic acid

Prophylaxis of deep vein thrombosis and pulmonary embolism.

Prevention of graft occlusion after Coronary Artery Bypass Grafting (CABG). Coronary angioplasty, except during the acute phase (PCI). Prevention of arteriovenous anastomosis for renal dialysis.

History of unstable angina pectoris, except during the acute phase.

Prevention of cardiovascular morbidity in patients suffering from stable angina pectoris.

Secondary prevention of transient ischaemic attacks (TIA) and ischaemic cerebrovascular accidents (CVA), provided intracerebral haemorrhages have been ruled out.

Secondary prevention of myocardial infarction.

Acetylsalicylic acid has analgesic, antipyretic and anti-inflammatory actions. It is indicated for the relief of headache, toothache, migraine, neuralgia, sore throat, dysmenorrhoea and the symptomatic relief of influenza, feverishness, rheumatic pains, sciatica, lumbago, fibrositis, muscular aches and pain.

Migraine with or without aura.

The recommended loading dose is 150-450 mg. The loading dose is administered as soon as possible after onset of symptoms.

Acetylsalicylic acid has analgesic and anti-inflammatory actions. It is indicated for the relief of headache, toothache, migraine, neuralgia, sore throat, dysmenorrhoea and the symptomatic relief of influenza, rheumatic pains, sciatica, lumbago, fibrositis, muscular aches and pain.

Acetylsalicylic acid is contraindicated in severe renal impairment.

Acetylsalicylic acid is contraindicated in severe cardiac failure.

Acetylsalicylic acid is contraindicated in severe hepatic impairment.

Contraindications for acetylsalicylic acid:

• Active, or history of recurrent peptic ulcer and/or gastric/intestinal haemorrhage, or other kinds of bleeding such as cerebrovascular haemorrhages.
• Haemorrhagic diathesis; coagulation disorders such as haemophilia and thrombocytopenia.

Low doses (up to 100 mg/day): Clinical studies indicate that doses up to 100 mg/day for restricted obstetrical use, which require specialised monitoring, appear safe.

Doses of 100- 500 mg/day: There is insufficient clinical experience regarding the use of doses above 100 mg/day up to 500 mg/day. Therefore, the recommendations below for doses of 500 mg/day and above apply also for this dose range.

Doses of 500 mg/day and above: Inhibition of prostaglandin synthesis may adversely affect the pregnancy and/or the embryo/foetal development.

Data from epidemiological studies suggest an increased risk of miscarriage and of cardiac malformation and gastroschisis after use of a prostaglandin synthesis inhibitor in early pregnancy. The absolute risk for cardiovascular malformation was increased from less than 1%, up to approximately 1.5%. The risk is believed to increase with dose and duration of therapy. In animals, administration of a prostaglandin synthesis inhibitor has been shown to result in increased pre- and post-implantation loss and embryo-foetal lethality. In addition, increased incidences of various malformations, including cardiovascular, have been reported in animals given a prostaglandin synthesis inhibitor during the organogenetic period. During the first and second trimester of pregnancy, acetylsalicylic acid should not be given unless clearly necessary. If acetylsalicylic acid is used by a woman attempting to conceive, or during the first and second trimester of pregnancy, the dose should be kept as low and duration of treatment as short as possible.

During the third trimester of pregnancy, all prostaglandin synthesis inhibitors may expose the foetus to:

• cardiopulmonary toxicity (with premature closure of the ductus arteriosus and pulmonary hypertension);
• renal dysfunction, which may progress to renal failure with oligo-hydroamniosis;

the mother and the neonate, at the end of pregnancy, to:

• possible prolongation of bleeding time, an anti-aggregating effect which may occur even at very low doses.
• inhibition of uterine contractions resulting in delayed or prolonged labour.

Consequently, acetylsalicylic acid at doses of 100 mg/day and higher is contraindicated during the third trimester of pregnancy.

Acetylsalicylic acid reduces uricosurics effects of probenecid, benzbromarone, sulfinpyrazone. Salicylates reverse the effect of probenecid. The combination should be avoided.

Acetylsalicylic acid should not be used in patients undergoing heparin therapy.

Methotrexate (used at doses >15 mg/week): The combined drugs, methotrexate and acetylsalicylic acid, enhance haematological toxicity of methotrexate due to the decreased renal clearance of methotrexate by acetylsalicylic acid.

Methotrexate (used at doses <15 mg/week): The combined drugs, methotrexate and acetylsalicylic acid, may increase haematological toxicity of methotrexate due to decreased renal clearance of methotrexate by acetylsalicylic acid. Weekly blood count checks should be done during the first weeks of the combination. Enhanced monitoring should take place in the presence of even mildly impaired renal function, as well, as in elderly.

Acetylsalicylic acid is not recommended for use in patients with severe glucose 6-phosphate dehydrogenase deficiency (G6PD) deficiency, as acetylsalicylic acid may cause haemolysis or haemolytic anemia. Factors that may increase the risk of hemolysis are e.g. high dosage, fever or acute infections.

Acetylsalicylic acid should not be used in haemophilia and thrombocytopenia.