Tenofovir DF expanded access. Criteria for U.S. program

Antiviral Nucleoside InhibitorsAntiviral nucleoside inhibitors are structural analogs of natural nucleosides that interfere with viral DNA or RNA synthesis. These compounds selectively target viral polymerases due to their resemblance to host nucleosides, thereby disrupting viral genome replication.Mechanism of Acyclovir ActionAcyclovir is a guanosine analog with a three-carbon acyclic side chain. It selectively targets herpes simplex virus type 1 (HSV-1), herpes simplex virus type 2 (HSV-2),...

Post-approval, manufacturers may modify an approved new or generic drug product. Such modifications can encompass alterations in the Active Pharmaceutical Ingredient (API), manufacturing process, formulation, batch size, manufacturing site, and container closure system (FDA Guidance for Industry, April 2004). Often, a drug product may undergo multiple changes.These modifications require careful evaluation to determine their potential impact on the drug product's identity, strength, quality,...

Subviral agents are infectious entities that resemble viruses but lack one or more viral components, such as a capsid or essential replication machinery. These agents include viroids, prions, and satellites, each possessing distinct structural and functional characteristics that influence their mode of infection and replication.Viroids are the simplest subviral agents, consisting of circular, single-stranded RNA molecules without a protein coat. They exclusively infect plants, relying entirely...

Drugs, the chemical agents used in diagnosing, treating, or preventing diseases, undergo a four-phase process of development: pharmaceutic, pharmacokinetics, pharmacodynamics, and therapeutic.
The pharmaceutical phase focuses on leveraging the physicochemical properties of the drug to design and manufacture an effective product. Variants include orally administered tablets or capsules, topical creams or ointments, and parenteral-delivery solutions or emulsions.
The pharmacokinetic phase...

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...

Prescription drugs require a prescription from a medical practitioner and can only be obtained from a pharmacy. They have many applications, including treating pain, anxiety, and hypertension.
The misuse and addiction to prescription drugs is a growing problem that can affect people of all age groups, specifically teenagers. This can happen when prescription medications are used in ways not intended by the prescriber, such as taking someone else's prescription or using medication for...