Master of Pharmacy: Pharmacology and Therapeutics Flashcards

Hyperkalemia and a dry cough that won't go away are side effects of which of these drug classes?

Answer: ACE inhibitors

Angiotensin-converting enzyme (ACE) inhibitors are a class of medications commonly used to treat high blood pressure and heart failure. Two well-known side effects associated with ACE inhibitors are hyperkalemia (elevated potassium levels in the blood) and a persistent, dry cough, which occurs in a significant percentage of patients due to the accumulation of bradykinin.

Which of these medications is a good alternative for the treatment of gonorrhea?

Answer: Ceftriaxone

Ceftriaxone is a third-generation cephalosporin antibiotic that is highly effective and widely recommended as a first-line treatment for gonorrhea, often in combination with azithromycin. It is a potent bactericidal agent that targets the bacterial cell wall, making it a reliable choice for combating this sexually transmitted infection.

Which of these vitamins deficiencies causes pernicious anemia?

Answer: Vitamin B12

Pernicious anemia is a type of megaloblastic anemia caused by a deficiency in Vitamin B12 (cobalamin). This deficiency typically arises from an inability to absorb B12 due to a lack of intrinsic factor, which is necessary for its absorption in the small intestine, leading to impaired red blood cell production.

What kind of drug toxicity causes the level of N-acetyl-p-benzoquinone imine to rise?

Answer: Acetaminophen

Acetaminophen (paracetamol) overdose leads to the accumulation of a toxic metabolite called N-acetyl-p-benzoquinone imine (NAPQI). Normally, NAPQI is detoxified by glutathione, but in overdose, glutathione stores are depleted, allowing NAPQI to bind to liver cells and cause severe hepatotoxicity.

Which of the following is a drug that blocks the proteasome?

Answer: Bortezomib

Bortezomib is a proteasome inhibitor, a type of anticancer drug used primarily in the treatment of multiple myeloma and mantle cell lymphoma. It works by reversibly inhibiting the 26S proteasome, a protein complex that degrades ubiquitinated proteins, leading to the accumulation of misfolded proteins and induction of apoptosis in cancer cells.

All of these drugs for high blood pressure are safe during pregnancy, except for which one?

Answer: Ramipril

Ramipril is an ACE inhibitor, and ACE inhibitors are contraindicated during pregnancy, especially in the second and third trimesters, due to their potential to cause severe fetal renal damage, oligohydramnios, and other adverse outcomes. Labetalol, nifedipine, and methyldopa are generally considered safer options for managing hypertension in pregnant women.

Which of these medicines is a good way to help people with familial Mediterranean fever (FMF)?

Answer: Colchicine

Colchicine is the cornerstone of treatment for familial Mediterranean fever (FMF), a genetic inflammatory disorder. It works by inhibiting microtubule polymerization and neutrophil migration, thereby reducing the frequency and severity of inflammatory attacks characteristic of FMF.

From which medication is Mesna administered to decrease the likelihood of hemorrhagic cystitis?

Answer: Cyclophosphamide

Mesna (2-mercaptoethane sulfonate sodium) is administered with cyclophosphamide (and ifosfamide) to prevent hemorrhagic cystitis, a severe bladder inflammation that can be a side effect of these chemotherapy drugs. Mesna detoxifies acrolein, a urotoxic metabolite of cyclophosphamide, in the bladder, thereby protecting the urinary tract.

For which of the following medicines does pyridoxine work as an effective countermeasure?

Answer: Isoniazid

Pyridoxine (Vitamin B6) is routinely co-administered with isoniazid, an antitubercular drug, to prevent isoniazid-induced peripheral neuropathy. Isoniazid can interfere with pyridoxine metabolism, leading to a functional deficiency of B6, which is crucial for nerve function. Supplementing with pyridoxine mitigates this neurotoxic side effect.

In the Vaughan-Williams classification of antiarrhythmic medications, which group acts as inhibitors of potassium channels?

Answer: Class III

The Vaughan-Williams classification categorizes antiarrhythmic drugs based on their primary electrophysiological effects. Class III antiarrhythmics, such as amiodarone and sotalol, primarily act by inhibiting potassium channels. This inhibition prolongs the action potential duration and the effective refractory period in cardiac cells, thereby preventing re-entrant arrhythmias.

Explain the concept of a competitive antagonist.

Answer: A molecule that binds to the binding site for the endogenous agonist of the receptor, causing a conformational change that does not yield a biological response.

A competitive antagonist is a molecule that binds reversibly to the same active site on a receptor as the endogenous agonist. By occupying the binding site, it prevents the agonist from binding and activating the receptor, but it does not produce a biological response itself. This competition can be overcome by increasing the concentration of the agonist.

How do you know if a drug is safe if you compare doses that cause toxic effects 50% of the time with doses that cause acceptable therapeutic effects 50% of the time?

Answer: Therapeutic Index

The Therapeutic Index (TI) is a quantitative measure of the relative safety of a drug. It is calculated as the ratio of the dose that produces toxicity in 50% of the population (TD50) to the dose that produces a therapeutically desired effect in 50% of the population (ED50). A higher therapeutic index indicates a wider margin between effective and toxic doses, suggesting a safer drug.

What does "bioisostere" mean?

Answer: A structural moiety that is similar electronically and sterically to a moiety present in the structure of a high affinity ligand for a given receptor.

A bioisostere is a structural moiety that can be substituted for another moiety in a drug molecule, resulting in a new compound with similar biological properties. These substitutions are designed to maintain or improve the ligand's affinity for its target receptor by mimicking the electronic and steric characteristics of the original moiety. This concept is crucial in medicinal chemistry for optimizing drug potency, selectivity, and pharmacokinetic profiles.

What kind of macromolecules will a ligand (usually) bind to without making a chemical bond?

Answer: DNA, enzymes, receptors

Ligands typically bind to macromolecules like DNA, enzymes, and receptors through non-covalent interactions. These interactions include hydrogen bonds, ionic bonds, van der Waals forces, and hydrophobic interactions, which are transient and reversible. This non-covalent binding allows the ligand to exert its biological effect without permanently altering the macromolecule's chemical structure, enabling dynamic regulation of biological processes.

As the acidity of an acid increases, its pKa value decreases.

Answer: Stronger

The pKa value is a measure of an acid's strength; specifically, it is the negative logarithm of the acid dissociation constant (Ka). A lower pKa value indicates a stronger acid because it means the acid dissociates more readily in solution, releasing more protons. Conversely, a higher pKa value signifies a weaker acid.

Is it possible to determine the acidity strength of an acid solely based on its pKa value?

Answer: No, you need additional information.

While pKa directly quantifies an acid's intrinsic strength (lower pKa means stronger acid), determining its *effective* strength or behavior in all scenarios requires additional information. Factors like the solvent, temperature, concentration, and the presence of other species can influence an acid's dissociation and reactivity in a specific environment. Therefore, pKa alone might not fully describe its acidic properties in complex systems, especially outside of standard aqueous conditions.