clinical application and toxicology

What is a Loading Dose and when is it used?

A large initial dose used to rapidly achieve the desired therapeutic plasma concentration. Used in emergencies (e.g., serious infections, arrhythmias).

What is a Maintenance Dose?

The repeated dose that maintains the steady-state concentration within the therapeutic window.

If a patient has lost more than ______ of kidney function, the dosage of renally excreted drugs must be adjusted.

50%.

What is Therapeutic Drug Monitoring (TDM)?

The clinical practice of measuring specific drug levels in the blood to optimize dosage, especially for drugs with a narrow therapeutic index.

What is a Prodrug? Give an example.

A pharmacologically inactive molecule that is biotransformed inside the body into an active drug (e.g., Codeine -> Morphine via CYP2D6; Clopidogrel -> active metabolite via CYP2C19).

What is the "Prescribing Cascade"?

When an adverse drug effect is misinterpreted as a new disease, leading to the prescription of another, unnecessary drug.

What is the primary use of Activated Charcoal in poisoning?

To adsorb poisons in the GI tract, reducing systemic absorption. It is most effective if given within 1 hour of ingestion.

For which poisons is Activated Charcoal INEFFECTIVE? (Name two)

Ethanol, Methanol, Iron, Lithium, Strong acids/bases (corrosives).

What is the antidote for Acetaminophen (Paracetamol) poisoning?

N-Acetylcysteine (NAC). It works by replenishing glutathione, which detoxifies the toxic metabolite NAPQI.

What is the antidote for Opioid overdose (e.g., morphine)?

Naloxone.

What is the antidote for Benzodiazepine overdose?

Flumazenil.

What is the antidote for Methanol or Ethylene Glycol poisoning?

Fomepizole or Ethanol. They work by inhibiting alcohol dehydrogenase, preventing the formation of toxic metabolites.

What is the antidote for Organophosphate poisoning?

Atropine (blocks