Drugs in Medicine | Biology for GCSE/IGCSE - Year 11 PDF Download

What is a Drug?

• A drug is any substance taken into the body that alters or influences chemical reactions within the body.
• Certain drugs, like antibiotics, are classified as medicinal substances used to address symptoms or causes of diseases. For instance, antibiotics combat bacterial infections effectively.
  • The liver plays a crucial role in drug metabolism, serving as the primary site where many drugs are processed and broken down.
• Specifically, the liver is responsible for the metabolism of drugs, ensuring that they can be effectively utilized or excreted by the body.

Antibiotics

• Antibiotics are chemical substances produced by certain fungi or bacteria that impact the functioning of bacterial cells, either by disrupting their structure or function or by inhibiting their reproduction.
• These substances are specifically effective against bacteria and do not work against viruses.
• Antibiotics target processes and structures unique to bacterial (prokaryotic) cells, without causing harm to animal cells.

Antibiotic Resistance & Use

• Since the discovery of the first antibiotic in 1928, numerous antibiotics have been developed and widely used.
• Commonly prescribed antibiotics are losing effectiveness due to various reasons, such as overuse, unnecessary prescriptions, patients not completing full courses, and extensive agricultural use.

Reasons for Antibiotic Ineffectiveness

• Overuse of antibiotics in both medical and agricultural settings contributes to reduced effectiveness.
• Patients not finishing prescribed antibiotic courses can lead to antibiotic resistance.
• Agricultural practices involve mass antibiotic use to prevent diseases in livestock, even when animals are healthy, further decreasing antibiotic efficacy.

Impact of Antibiotic Resistance

• Antibiotic resistance is on the rise, making common bacterial infections harder to treat.
• Superbugs like MRSA (Methicillin-resistant Staphylococcus aureus) are becoming more prevalent.

Prevention of Antibiotic Resistance

• Use antibiotics only when necessary to avoid contributing to resistance.
• Complete the full course of antibiotics as prescribed, even if symptoms improve early.