Antiinfective

Antiinfective

Antiinfectives are a class of medications used to treat infections caused by microorganisms, including bacteria, viruses, fungi, and parasites. These agents work by either killing the infectious agents or inhibiting their growth. Antiinfectives are crucial in the management of infectious diseases and are categorized into several types based on their mechanism of action and the type of organisms they target.

Types of Antiinfectives

Antiinfectives can be broadly classified into the following categories:

Antibiotics

Antibiotics are used to treat bacterial infections. They can be further divided into several classes, including:

• Penicillins - These are beta-lactam antibiotics that inhibit bacterial cell wall synthesis.
• Cephalosporins - Similar to penicillins, they also disrupt cell wall synthesis but have a broader spectrum of activity.
• Macrolides - These inhibit bacterial protein synthesis by binding to the 50S ribosomal subunit.
• Tetracyclines - These inhibit protein synthesis by binding to the 30S ribosomal subunit.
• Fluoroquinolones - These interfere with bacterial DNA replication by inhibiting DNA gyrase and topoisomerase IV.

Antivirals

Antivirals are used to treat viral infections. They work by inhibiting the replication of viruses. Examples include:

• Acyclovir - Used primarily for herpes simplex virus infections.
• Oseltamivir - Used for influenza virus infections.
• Antiretrovirals - Used in the treatment of HIV/AIDS.

Antifungals

Antifungals are used to treat fungal infections. They can be systemic or topical, depending on the type and severity of the infection. Examples include:

• Azoles - Inhibit the synthesis of ergosterol, a key component of fungal cell membranes.
• Echinocandins - Inhibit the synthesis of glucan in the fungal cell wall.

Antiparasitics

Antiparasitics are used to treat infections caused by parasites. They include:

• Antimalarials - Used to treat malaria, caused by Plasmodium species.
• Antiprotozoals - Used to treat infections caused by protozoa, such as Giardia and Trichomonas.
• Antihelminthics - Used to treat infections caused by helminths (worms).

Mechanism of Action

Antiinfectives work through various mechanisms, including:

• Inhibition of cell wall synthesis - As seen in beta-lactam antibiotics like penicillins and cephalosporins.
• Inhibition of protein synthesis - As seen in macrolides, tetracyclines, and aminoglycosides.
• Inhibition of nucleic acid synthesis - As seen in fluoroquinolones and some antivirals.
• Disruption of cell membrane integrity - As seen in antifungals like amphotericin B.

Resistance

Microorganisms can develop resistance to antiinfectives through various mechanisms, such as:

• Genetic mutations - Leading to changes in the target site of the drug.
• Efflux pumps - That expel the drug from the cell.
• Enzymatic degradation - Such as beta-lactamases that degrade beta-lactam antibiotics.

Resistance is a significant concern in the treatment of infectious diseases and necessitates the development of new antiinfective agents and strategies.

Also see

• Antibiotic resistance
• Antimicrobial stewardship
• Infectious disease
• Pharmacology