Acetylsalicylic Acid (ASA), commonly known as aspirin belongs to a group of drugs called non-steroidal anti-inflammatory drugs (NSAIDS) and falls in the chemical case called salicylates. Historically, the drug was naturally extracted from the willow plant and other salicylate rich plants but is currently synthesised in the lab.
Dr Godfrey S. Bbosa of the department of Pharmacology and Therapeutics at Makerere University College of Health Sciences says: “ASA is a wonder drug that has been used for thousands of years for various purposes.”
It is one of the most commonly used drugs for treating mild to moderate pain, and fevers. Some of the therapeutics uses of aspirin are as an analgesic as it relieves pain without anaesthesia or loss of consciousness, an antipyretic because it reduces a fever, and as an anti-inflammatory drug because it lowers inflammation when used in high doses.
Dr Bbosa says it is also used to deal with pre-eclampsia and hypertension during pregnancy as it inhibits production of thromboxane (TXA2)
Therefore, at various doses, this drug addresses different conditions: A low dose is between 75-81 milligrammes per day and this dosage can be used as an antiplatelet medication preventing blood clots from forming. Dr Barbra Kakande, a cardiologist at UMC Victoria Hospital, says Aspirin is a blood thinner used if a patient has a problem with the blood flowing to the heart, brain or to the lower limbs.
She adds that this is usually caused by atherosclerosis (a disease in which plaque builds up inside your arteries) causing angina (a type of chest pain caused by reduced blood flow to the heart). Other causes include heart attack, an ischemic stroke (occurs when the arteries to the brain become narrowed or blocked, causing severely reduced blood flow) or lower limb artery blockage putting the heart, brain and limbs at risk of injury or death.
Dr Bbosa adds that this low dose can also be given to prevent heart attacks in patients with cardiovascular disease by preventing clot formation. However, this dose is not meant to work as treatment but rather as a preventative measure for stroke as well as colorectal cancer.
High dose aspirin
It can treat or help to reduce symptoms of rheumatic fever, rheumatic arthritis, other inflammatory joint conditions, and pericarditis (inflammation of the pericardium - the fibrous sac surrounding the heart).
However, to Dr Bbosa, aspirin is not supposed to be taken by children or teenagers. “Many parents may want to use it when a child has flu, influenza or viral related fevers to bring down the temperature. The danger with this is that the child could develop Reye’s syndrome which causes swelling in the liver and brain and the symptoms are confusion, seizures and loss of consciousness liver disturbance, nausea, vomiting. This could culminate in encephalopathy (brain disease, damage, or malfunction whose major symptom is an altered mental state),” Dr Bbosa says.
He adds that with this syndrome, the liver will fail to regulate the ammonia levels within the body to the point where it gets to the brain destroying the brain cells. The alternative medicine is paracetamol.
Dangers of poisoning
The most common side effect is salicylism. In this case, one tends to get tinnitus (a ringing in the ear), hearing problems, confusion, and convulsions. Dr Bbosa says beyond that, one may go into coma which sometimes culminates in death. More to that, because aspirin stimulates the respiratory centre, the person will experience hyperventilation which will lead to respiratory alkalosis (increased alkalinity in the blood).
Uncoupling of the oxidation process
Dr Bbosa says people who suffer from this condition cannot use oxygen for glucose utilisation (aerobic respiration). Therefore, they will use anaerobic respiration (glucose breaks down without oxygen and the chemical reaction transfers energy from glucose to the cell). Therefore, rather than form carbon dioxide and water, lactic acid build-up is formed hence lactic acidosis.
Prevents prostaglandins production
Dr Bbosa says prostaglandins are produced from arachidonic acid but aspirin overdose averts their formation by inhibiting cyclooxygenase (COX) enzyme. Prostaglandins are used to set body temperature in the brain. Therefore, people with this condition will experience higher temperature since there is no temperature control.
From arachidonic acid, the body also produces thromboxane (TXA) which is important in platelet aggregation. When someone is overdosed with aspirin and they get an accident or have haemophilia, they will bleed to death. “That is because their blood lacks clotting factors,” Dr Bbosa explains.
He adds that aspirin poisoning may also worsens peptic ulcers since an overdose of aspirin prevents the production of prostaglandins E2. It is these that are responsible for the production of mucus in the gastral intestinal tract (GIT) which coats the GIT hence preventing acid attack. “Without prostaglandins E2, mucus production is reduced resulting in increased bleeding or gastritis,” Dr Bbosa explains.
There might also be tocolytic effect, which leads to uterine wall relaxation. “So if a woman is in labour and takes aspirin, labour delays. That means that it can also prevent a threatened abortion or miscarriage,” Dr Bbosa says.
Salicylism or aspirin poisoning can be treated by resuscitation followed by gastric decontamination by administering activated charcoal which absorbs the aspirin in the gastrointestinal tract. One may also be given an intravenous (IV) hydration containing dextrose such as dextrose five per cent in water.
For alkalinisation of urine, sodium bicarbonate is given in a significant aspirin overdose (salicylate level greater than 35mg, six hours after ingestion).
Haemodialysis (a process of purifying the blood of a person whose kidneys are not working normally) can be used to enhance the removal of salicylate from the blood. It is usually used in those who are severely poisoned and it great for correcting acid-base abnormalities while removing salicylate.
When to prescribe
Dr Barbra Kakande, a cardiologist at UMC Victoria Hospital, says if an artery blockage is not significant and the organs are not at risk, then the effects of thinning of the blood by aspirin, may instead manifest with bleeding in the brain, stomach, colon, and skin. “Therefore, before prescribing the drug, the risk of dying from or complications to the organs have to outweigh the risk of the patient getting side effects from the drug,” she adds.
Dr Godfrey S. Bbosa of the department of Pharmacology and Therapeutics at Makerere University College of Health Sciences, notes that continuous use of aspirin to prevent colon cancer can cause bleeding owing to lack of mucus in the colon. “Therefore, look at the risk factors such as diet, feeding habits and toilet habits and work on them. For instance, eat high fibre foods and stop withholding the use of the toilet,” he explains.
Under what conditions do you prescribe aspirin?
We do not give aspirin to children at all. In cases of pain, inflammation, and fevers, we use alternative drugs such as paracetamol and ibuprofen.
Dr Theresa Were Piloya, paediatrician
I would give aspirin to a patient with clotting tendencies as a preventative measure. I would also give it to a patient with hypertension to avoid the risks of getting a stroke.
Dr Franklin Wasswa, general physician
Junior aspirin (75mg) though formally used for children is now used for people with hypertension. The general aspirin which is 375mg is ideal people that are prone to heart attacks.
Dr Micheal Oling, surgeon
How to take
•If your doctor has directed you to take this medication, take it exactly as prescribed.
•Take by mouth and drink a full glass of water unless your doctor tells you otherwise.
•Do not crush or chew. Doing so can release all of the drug at once, increasing the risk of side effects.
•If you are taking this medication for self-treatment of headache, seek immediate medical attention if you also have slurred speech, weakness on one side of the body, or sudden vision changes. Before using this drug, consult a doctor or pharmacist if you have headaches caused by head injury, coughing, or bending, or if you have a headache with persistent/severe vomiting, fever, and stiff neck.
•If your condition persists or worsens, tell your doctor immediately.