Veterinary Pharmacology: Routes, Receptors, and Drug Dynamics

What are parenteral routes?

Routes absorbed outside the GI tract.

Name the parenteral injection routes.

IM (intramuscular), IV (intravenous), SQ (subcutaneous), ID (intradermal), IP (intraperitoneal).

What is the purpose of intraperitoneal injections?

Usually used to euthanize pocket pets or to numb the abdomen of dogs and cats.

How can you locate the heart for intracardiac injections?

By pulling the elbow back; the tip of the elbow is a rough estimate for the heart's location.

What is transdermal administration?

Administration that is neither parenteral nor enteral, as it does not enter systemic circulation directly.

What forms of medication are given enterally?

Pills, tablets, capsules.

What is a bolus in intravenous injections?

An injection given all at once, quickly.

What is CRI in intravenous administration?

Constant Rate Infusion, where medication is dripped into the vein over time.

What is an extravascular injection?

Accidental injection of a drug outside of the vein, which can cause tissue necrosis.

What is the flow direction of blood in arteries?

To the organs.

Why is injecting a drug into an artery dangerous?

Arteries have high pressure, which can cause blood to gush out.

What does MDI stand for?

Meter Dose Inhaler.

What is albuterol used for?

It is a rescue medication for asthma.

What is the difference between rescue and chronic medications?

Rescue medications are used for immediate relief, while chronic medications are taken daily to manage a condition.

What does EDT stand for?

Endotracheal tube.

What are isoflurane and cenoflurane?

Halogenic anesthetics commonly used in veterinary medicine.

What is epistaxis?

Nosebleed, which can be unilateral or bilateral.

What is the therapeutic goal in pharmacology?

To maintain drug concentrations within the therapeutic range.

What is the therapeutic range?

An acceptable range of drug concentrations that produce beneficial effects without significant toxicity.

What is the difference between peak and trough concentrations?

Peak concentration is the highest drug concentration, while trough concentration is the lowest.

What is pharmacokinetics?

How a drug moves into, through, and out of the body.

What is pharmacodynamics?

How a drug produces its effect on the body.

What is passive diffusion?

Movement of drug molecules down the concentration gradient without using active cellular energy.

What is the role of lipophilicity in drug absorption?

A drug must be lipophilic to passively diffuse through the cell membrane.

What is bioavailability?

The extent to which a drug makes it into systemic circulation, indicated by the letter F.

How does the route of administration affect bioavailability?

IV has 100% bioavailability; IM is slightly less, while PO and SC have significantly lower bioavailability.

What is dissolution in pharmacology?

The process of breaking down dosage forms to individual molecules for absorption.

What is the first pass effect?

The phenomenon where the liver removes a significant amount of a drug before it reaches systemic circulation.

What is the hepatic portal system?

The system of blood vessels that moves blood from the capillaries of the GI tract to the liver.

How does tissue perfusion affect drug absorption?

Well-perfused tissues absorb drugs more quickly than poorly perfused tissues.

What happens to capillaries in a cold environment?

Vasoconstriction occurs, reducing blood flow.

What effect does warming have on tissue perfusion?

Warming causes vasodilation, enhancing perfusion and increasing drug absorption.

What is the blood-brain barrier?

A barrier formed by tightly packed endothelial cells in brain capillaries that prevents many drugs from entering brain tissue.

What are the main reasons drugs fail to cross the blood-brain barrier?

Large molecular size, high ionization/low lipid solubility, and efflux pumps like P-glycoprotein.

Name a common veterinary drug that does not cross the BBB effectively.

Maropitant (Cerenia), an anti-nausea medication.

What is the significance of fenestrations in blood capillaries?

Fenestrations allow for the movement of water and small molecules, facilitating drug distribution.

What does 'drug is the key, receptor is the lock' imply?

Each receptor has a unique shape, allowing only certain drugs to bind and produce a response.

What is efficacy in pharmacology?

A drug's ability to activate its receptor and initiate a biological response.

What is an agonist drug?

A drug that binds to a receptor and produces a desired effect.

What is an antagonist drug?

A drug that binds to a receptor but does not produce a significant effect, often blocking other substances.

What are G Protein-Coupled Receptors (GPCRs)?

Transmembrane proteins linked to intracellular G proteins, involved in various signaling pathways.

What are ligand-gated ion channels?

Channels that open or close in response to the binding of a molecule, allowing ions to flow across membranes.

What is the role of intracellular receptors?

They bind lipid-soluble drugs to alter gene transcription within the cell.

What are mu (μ) receptors responsible for?

They mediate strong pain relief and are targeted by drugs like morphine.

What is the function of kappa (κ) receptors?

They provide moderate pain relief and sedation with fewer side effects.

What is the role of delta (δ) receptors?

They help control pain transmission in the spinal cord.

What is NARCAN® Nasal Spray used for?

It is used for the treatment of known or suspected opioid overdose.

What is a partial agonist?

A drug that produces a weaker response compared to a full agonist.

What is intrinsic activity in pharmacology?

The ability of a drug to produce a cellular effect when bound to its receptor.

What is the significance of drug affinity?

It refers to how strongly a drug binds to its receptor; higher affinity means a stronger bond.

What happens to drug absorption in a hot environment?

Vasodilation occurs, which can dramatically increase drug absorption.

What is the effect of sympathetic nervous system activation on drug absorption?

It can cause vasoconstriction, reducing the effectiveness of subcutaneously administered drugs.

What is the role of beta blockers?

They block sympathetic nervous system responses to help calm patients.