LOGIC LOGIC 2019 Spring Vol 18 No 3 | Page 57

Allergic reactions rarely occur the first time we take a medication, it requires exposure to the drug to develop the immune response, therefore most severe reactions will occur with subsequent doses. (3, 5). These occur not only with prescribed medications but also natural products. Symptoms of allergy can be as mild as hives, rash, itchy skin or on the more severe end of the spectrum the symptoms can include swollen face, throat tightness, trouble breathing, light-headedness, blisters, reddened skin or whole-body shock with life-threatening low blood pressure (1,5,10). Beware, the pseudo allergic reactions, these mimic those caused by IgE antibodies but are not initiated by IgE, these occur as a result of histamine release and other non-immune mechanisms and these can occur the first time a drug is taken. These are as potentially life-threatening as a true allergic reaction; the symptoms and the treatment are the same for both. The most common drugs involved include: morphine, opiates, anaesthetic muscle relaxants and contrast media. Non-steroidal drugs and aspirin have been noted to cause urticaria and asthma and Spring 2019 L.O.G.I.C anaphylaxis in people. (3, 8). susceptible There are two allergy response types: Rapid onset within 1-2 hours of ingestion, this is IgE mediated. This is the one which needs immediate attention as the symptoms include: abdominal pain, confusion, urticaria, wheezing, hoarse voice, dizziness or fainting, rapid pulse and/or heart palpitations, angioedema, bronchospasm and anaphylaxis. (5, 6) Delayed onset which often occurs with antibiotics, this is IgG mediated. Can occur up to 10 days after initiating treatment and the main symptom is rash. The confusing factor with this is that the rash may be related to the illness. There are more serious delayed immune reactions involving rash in conjunction with systemic symptoms including: Serum Sickness-like reaction (most commonly associated with cephalosporins) Stevens-Johnson syndrome (most commonly associated with sulphonamides) Asceptic Meningitis (most commonly associated with trimethoprim/co-trimoxazole) (5, 6) SIDE EFFECT: These can seem like an allergic reaction but in reality, is just a sensitivity felt by the body to a new medication and is not immune mediated. (1,5) According to the World Health Organisation a side effect is an unintended effect of a drug occurring at a dose which is normally used and is related to the pharmacological properties of the medication. (7) Side effects are more common than allergy but often misinterpreted and reported by patients as an allergy. The most common symptoms include: nausea, lack of energy, muscle aches, hard to sleep, coughing, wheezing, stuffy nose, stomach cramps, diarrhoea, constipation, ringing in the ears, easy bruising. (1, 5). INTOLERANCE: This is a sensitivity reaction to a medicine which does not involve the immune system. It is dependent on two factors: the pharmacological action of the medicine and the patient susceptibility factors. This means that these people usually have a low threshold for developing adverse effects or exaggerated side effects or developing a side effect not normally associated with the medication. (6) 55