[Systemic antifungals. Pharmacodynamics and pharmacokinetics]

Mercedes Catalán1, Juan Carlos Montejo

  • 1Servicio de Medicina Intensiva, Unidad Polivalente, Hospital Universitario 12 de Octubre, Avenida de Córdoba s/n, 28041 Madrid, Spain. mmcges@yahoo.es

Insights

New antifungal drugs offer improved treatment options for invasive fungal infections in critically ill patients. These agents provide diverse pharmacokinetic and pharmacodynamic profiles for better patient outcomes.

Area of Science:

  • Medical Mycology
  • Infectious Diseases
  • Critical Care Medicine

Background:

  • Invasive fungal infections (IFIs) are significant contributors to morbidity and mortality in critically ill, non-neutropenic patients.
  • Historically, treatment options for IFIs were limited to amphotericin B and flucytosine.
  • The therapeutic landscape for IFIs has expanded significantly in recent decades.

Purpose of the Study:

  • To review the expanded armamentarium of antifungal agents available for treating invasive fungal infections.
  • To highlight the introduction of newer antifungal drugs and their characteristics.

Main Methods:

  • Literature review of antifungal agents licensed in the past two decades.
  • Analysis of pharmacokinetic and pharmacodynamic profiles of available antifungal drugs.

Main Results:

  • Several new antifungal agents have been licensed, including itraconazole, fluconazole, lipid formulations of amphotericin B, voriconazole, and caspofungin.
  • These newer agents exhibit distinct pharmacokinetic and pharmacodynamic properties compared to older drugs.

Conclusions:

  • The availability of novel antifungal agents has broadened treatment options for IFIs.
  • Understanding the differing pharmacokinetic and pharmacodynamic profiles is crucial for optimizing therapy in critically ill patients.

Related Concept Videos

Antifungal Agents01:15

Antifungal Agents

Amphotericin B is a broad-spectrum antifungal agent that exploits structural differences between fungal and mammalian cell membranes. Its amphipathic structure—featuring a hydrophobic polyene-lactone ring and a hydrophilic region containing mycosamine and carboxylic acid groups—enables selective binding to ergosterol, a sterol predominantly found in fungal plasma membranes. This selective interaction underlies the drug’s antifungal activity, although weak binding to cholesterol contributes to...
Impact of Pharmacokinetic–Pharmacodynamic Models: Regulatory Decisions01:15

Impact of Pharmacokinetic–Pharmacodynamic Models: Regulatory Decisions

PK–PD modeling has significantly influenced FDA regulatory decisions, particularly drug approval, dosage optimization, and labeling. These models integrate pharmacokinetics (PK) and pharmacodynamics (PD) to predict drug behavior and effects, aiding in optimizing dosing regimens and enhancing the probability of clinical trial success.One notable example is Nesiritide (Natrecor®), a recombinant human brain natriuretic peptide for treating acute decompensated congestive heart failure (CHF).
Pharmacokinetics: Drug–Drug Interactions01:25

Pharmacokinetics: Drug–Drug Interactions

Drug interactions occur when the pharmacological effect of one drug is altered by another substance, either enhancing or diminishing its activity. The drug whose activity is altered is known as the object drug, and the substance causing the alteration is called the agent drug or the precipitant. The net effects of these interactions are mostly undesirable, leading to decreased effectiveness or increased adverse effects. In rare cases, interactions can be beneficial, such as the enhanced...
Pharmacokinetics: Drug–Food and Drug–Viral Interactions01:26

Pharmacokinetics: Drug–Food and Drug–Viral Interactions

A drug interaction occurs when the concurrent use of another drug, food, or an external substance alters the pharmacological activity of a drug. This interaction can modify the action of the original drug, affecting its effectiveness and safety.Drug–food interactions are significant as they impact drug absorption, metabolism, and excretion. For example, grapefruit juice is a well-known disruptor of drug metabolism. It inhibits the cytochrome P450 3A4 enzyme, crucial for the metabolism of many...
Pharmacogenetic Phenotypes: Alterations in Pharmacokinetics, Drug Targets and Biologic Milieu01:29

Pharmacogenetic Phenotypes: Alterations in Pharmacokinetics, Drug Targets and Biologic Milieu

Genetic variations significantly influence drug response through pharmacokinetics, receptor interactions, and biologic milieu modifications. Pharmacokinetic alterations impact drug metabolism and clearance, affecting efficacy and toxicity. Variants in drug-metabolizing enzymes, such as CYP2C9 and CYP2C19, alter drug activation and elimination. For example, CYP2C9 loss-of-function variants require lower warfarin doses to prevent excessive bleeding, while CYP2C19 variants reduce clopidogrel...
Bioavailability: Influencing Factors01:22

Bioavailability: Influencing Factors

Bioavailability refers to the extent and rate at which a drug reaches systemic circulation in its active form. Extent refers to the amount of the drug that makes it into circulation, while rate is the speed at which it enters circulation. It is influenced by several factors critical for optimizing drug formulations, dosing regimens, and therapeutic outcomes.Physicochemical properties of drugs and formulationsThe solubility, stability, and dissolution rate of a drug significantly impact its...