EVERY DRUG CAN BE TOXIC!1RD MAY 2018

WHAT DOES DRUG TOXICITY MEAN?In pharmacology, it refers to how harmful or poisonous a substance or drugs can be. Drug toxicity can occur when there’s a large amount of substance within the bloodstream which can have negative effects on the human body. If the drug accumulates too much, the human liver or kidney wouldn’t be able to cope.

WHAT IS ED50 AND HOW IS IT DETERMINED?Firstly, ED50 stands for median effective dose, which indicates the amount of substance needed to generate a therapeutic response and a quantal effect in 50% of the population that are exposed to the substance. ED50 can be calculated by dividing the number to people who have experienced therapeutic effects from the substance by the total amount of people who were introduced to the substance. Then multiply by a hundred.

WHAT IS LD50 AND HOW IS IT DETERMINED?Secondly, LD50 represented the lethal dose. This means when a quantity of a drug is given to a population, 50% of them will die. LD50 is

used by scientist to detect short-term poisoning of a drug. A way to predict the LD50 of a drug is by using the Miller and Tainter method. The experimental

percentage of mortality is transformed into probit. After obtaining the values, they can be plotted against the log of the dose. Then, the LD50 can be seen on the graph.

WARFARIN HAS A LOW THERAPEUTIC INDEXTherapeutic Index is frequently referred to as the therapeutic safety window or a therapeutic ratio. This ratio compares the concentration of when the drugs becomes toxic in the bloodstream and the concentration at which it is effective. Therefore, the smaller the therapeutic, the dangerous the drug is. If given, they must be carefully monitored and observed occasionally to detect any signs of drug toxicity. An example of a drug that has a low therapeutic index is warfarin. This drug is used by people to avoid harmful blood clots from growing or forming at all. This is beneficial for the patients because blood clots can trigger strokes, heart attacks and other life threating problems.

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Figure 1: Therapeutic effect (ED50) and Lethal effect (LD50) plotted on a dose response log graph

Figure 2: An example of a drug with low therapeutic index plotted on a dose response log graph

STEPS TO BE TAKENS TO LIMIT RISK OF TOXICITYThere are simple steps that can be taken at home to prevent accidental poisoning. Households that taken young children should be extremely cautious of these steps. In 2016, Australia alone had 1,808 deaths and 38 percentage of them were children under the age of 10

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Method for drug safety in your home:

1. Keep drugs in a closed package and ESPECIALLY in their original containers 2. Check that you’re taking the CORRECT DOSAGE at the RIGHT TIME! 3. Have a LIST of what you take just in case your family doctor need a copy4. Avoid taking any medication when a child is watching and NEVER refer to

medicine as candy.5. Once the drug reaches its expiry date, throw it away IMMEDIATELY!6. NEVER allow children to play with any kind of battery, as it is EXTREMELY toxic

if ingested