7.1. Evaluate the use of drugs to control and treat infectious disease

This guide will help you answer 7.1. Evaluate the use of drugs to control and treat infectious disease.

Infectious diseases are caused by microorganisms such as bacteria, viruses, fungi, or parasites. These microorganisms, called pathogens, can be spread from person to person, from animals to humans, or through contaminated environments.

Drugs used to control and treat these diseases work by targeting the specific pathogen responsible. Treatment aims to relieve symptoms, eliminate the cause, and lower the risk of spreading the infection. Some drugs act directly by killing the pathogen, while others stop the pathogen from multiplying or help the body fight off the invader.

Types of infectious diseases include:

• Bacterial infections (for example, tuberculosis, sepsis, pneumonia)
• Viral infections (for example, influenza, HIV, COVID-19)
• Fungal infections (for example, thrush, ringworm, athlete’s foot)
• Parasitic infections (for example, malaria, giardiasis)

Classes of Drugs Used

Different types of drugs are used based on the pathogen involved. Each group works in a unique way and has both strengths and weaknesses.

Antibiotics

Antibiotics fight bacterial infections. They work by destroying bacteria or stopping them from multiplying. Some are broad-spectrum, meaning they act on many types of bacteria. Others are narrow-spectrum and work on a specific type.

Common examples:

• Penicillins (like amoxicillin)
• Cephalosporins (like cefalexin)
• Macrolides (like erythromycin)
• Fluoroquinolones (like ciprofloxacin)

Strengths of antibiotics:

• Can cure many serious bacterial infections
• Reduce symptoms and prevent spread

Areas where antibiotics do not help:

• Viral infections (like cold or flu)
• Fungal or parasitic infections

Antivirals

Antivirals target viruses. They do not destroy the virus, but they stop or slow its ability to multiply.

Common examples:

• Acyclovir for herpes simplex
• Oseltamivir (Tamiflu) for influenza
• Antiretrovirals for HIV (like zidovudine, tenofovir)

Using antivirals can:

• Shorten the illness
• Lower the risk of serious complications
• Reduce spread

Antifungals

Antifungals treat infections caused by fungi. These drugs can be topical (applied to skin), oral (swallowed), or intravenous (injected into a vein).

Common examples:

• Clotrimazole for thrush and athlete’s foot
• Fluconazole for fungal infections of the mouth or blood
• Amphotericin B for severe systemic infections

Antifungals can be:

• Fungicidal (kill fungi)
• Fungistatic (stop fungi growing)

Antiparasitic Medicines

These treat infections caused by parasites.

Examples include:

• Mebendazole for threadworm and other intestinal worms
• Quinine and artemisinin-based drugs for malaria
• Metronidazole for Giardia and certain other parasites

They vary in their action but usually kill the parasite or stop it reproducing.

How Drugs Control and Treat Disease

Drug treatment aims to:

• Shorten the duration of symptoms
• Prevent complications
• Lower the risk of spreading the infection

Drugs may be used:

• As soon as infection is suspected
• Once a confirmed diagnosis has been made
• To prevent infection (prophylactic use), for example, giving antibiotics after exposure to meningitis or using antimalarials before travel

For some diseases, drug treatment is the only effective response. For other cases, it is given alongside non-drug approaches such as supportive care, good nutrition, or isolation.

Importance of Correct Drug Use

Correct use of drugs is key to effective treatment. This involves:

• Using the right drug for the infection
• Following the correct dose and timing
• Completing the prescribed course even if symptoms improve

Improper use contributes to the rise of drug resistance, especially for antibiotics. This makes infections harder to treat in future.

Benefits of Drug Treatments

Using drugs to control and treat infectious disease brings clear benefits. These improvements have transformed health outcomes around the world.

Key benefits include:

• Significantly lower death rates from infections that were once fatal
• Better quality of life for people who recover faster and avoid complications
• Reduced spreading of infectious diseases in communities
• Shorter hospital stays or quicker return to normal activities
• Prevention of long-term effects (for example, avoiding damage from untreated strep throat or tuberculosis)
• For some diseases (like HIV), long-term drug use changes an illness from fatal to manageable

By promptly treating infections, drugs help stop outbreaks and protect vulnerable people. This strengthens public health at both local and global levels.

Limitations and Risks of Drug Treatments

Despite clear benefits, drug treatments are not without problems. It is important to review all risks to make safe choices in care.

Common issues include:

• Side effects: All drugs may cause unwanted effects, from mild (rash or stomach upset) to severe (allergic reactions, organ damage).
• Drug resistance: Improper or overuse of antibiotics and other drugs gives rise to resistant bacteria, viruses, fungi, or parasites. Drug-resistant infections are much harder to treat and may spread in hospitals or the community.
• Treatment failures: Some drugs may not fully clear an infection, especially if taken incorrectly or if the pathogen is resistant.
• Limited options: For some infections, especially viral diseases like the common cold, vaccines or supportive care are the mainstay, not drugs.
• Impact on normal gut flora: For example, antibiotics can destroy helpful bacteria leading to yeast infections or digestive issues.
• Drug interactions: Some drugs may not be safe to take together.
• Allergic reactions: People may be allergic to certain medications, sometimes with dangerous results.

These risks underscore the need for careful diagnosis and expert prescribing.

Drug Resistance: A Growing Challenge

Drug resistance is one of the biggest issues in modern medicine. It is particularly common with bacteria, but occurs with viruses, fungi, and parasites as well.

Things that increase resistance include:

• Overuse of drugs (prescribing when not needed, like antibiotics for viral illnesses)
• People failing to complete the prescribed course
• Use of low-quality or counterfeit medicines
• Overuse in agriculture or animal farming

When resistance builds, former “wonder drugs” no longer work. This means common infections can again become deadly.

Examples:

• Methicillin-resistant Staphylococcus aureus (MRSA)
• Multidrug-resistant tuberculosis (MDR-TB)
• Resistant malaria

Fighting resistance involves improved prescribing, better infection control, and research to develop new drugs.

Considerations for Practice in Health and Social Care

When working in health and social care, workers must follow guidelines for safe and effective drug use:

• Use up-to-date local and national guidelines to inform choices
• Only trained staff should administer or advise on drugs
• Complete all training in medication handling
• Watch for side effects and report concerns without delay
• Educate people about the need to finish their course
• Support those receiving treatment, including managing side effects and checking for understanding
• Promote hand hygiene and infection control to reduce disease spread

Supporting people to take medicines properly is as important as the prescription itself.

The Role of Vaccines in Infectious Disease Control

Vaccines are not a treatment for active infection but play a key part in overall disease control. They are given to healthy people to train the immune system to prevent future infection.

Some diseases, like polio and measles, have been almost wiped out through vaccination rather than drugs.

Yet, for many infections, drugs remain essential — especially once someone becomes unwell or if no vaccine exists.

Ethical and Social Impacts

Treating infectious diseases with drugs is not just a medical matter. There are wider issues around access, cost, and equity.

Points to consider include:

• Some people, especially in low-income settings, cannot access new or expensive treatments
• Older adults, young children, or those with long-term conditions may respond differently to drugs and need extra support
• The spread of drug-resistant infections can have a major effect on wider society, not only individuals

Fair access to life-saving medicines is a key goal for global health organisations.

Real-World Examples

To better understand the use of drugs, let’s look at real-world cases.

Antibiotics for Pneumonia

Pneumonia is a serious lung infection, sometimes fatal in older adults or people with other illnesses. Antibiotic treatment has saved millions of lives. Yet, incomplete courses or over-prescription can drive resistance, limiting future treatment options.

Antivirals for HIV

Before antiretrovirals, HIV infections almost always led to AIDS and death. With combination drug treatment, people with HIV can live long, healthy lives. Adherence to treatment is critical, as missing doses risks drug resistance.

Antimalarial Drugs

Malaria has been one of the world’s deadliest diseases. Effective treatment with drugs like artemisinin has halved malaria deaths. New forms of drug-resistant malaria are a key concern and stress the continued need for research.

Antifungals for Thrush

Mild thrush often resolves with topical antifungals. In people with weakened immune systems, like those undergoing cancer treatment, effective antifungals prevent dangerous systemic infections.

Monitoring and Evaluating Effectiveness

Assessing how well drug treatments work is a routine part of practice. Key actions include:

• Regularly checking symptoms and vital signs
• Carrying out follow-up tests if needed
• Watching for side effects or complications
• Involving people in decisions about their care
• Reporting treatment failures or suspected resistance

Feedback helps improve care for future patients.

Supporting People Taking Drug Treatments

Workers should give people clear information about:

• What the drug is for and how it should be taken
• Possible side effects
• The importance of completing the treatment
• Signs that mean they should seek more help

This support helps people manage their health, reduces mistakes, and encourages confidence in health services.

Final Thoughts

Drug treatments for infectious disease have changed health and life expectancy around the world. Their use is vital, but must be carried out with care and responsibility. While drugs have major strengths in treating and controlling infection, they are not a cure-all.

Each person’s needs, the type of infection, and the community’s situation all matter when planning treatment. Drug resistance highlights the importance of using these medicines only when needed.

Good practice includes clear communication, use of evidence-based guidelines, and a commitment to learning. Workers in health and social care play a key role in ensuring medicines are used wisely, safely, and fairly.

Supporting people to understand and follow their treatment matters as much as the drugs themselves. Keeping these principles front of mind will continue to support better outcomes in the fight against infectious diseases.