Biologics + Surprises!
Two drugs both reduce receptor activation. One blocks the receptor directly, while the other binds the endogenous ligand before it reaches the receptor. What pharmacological property do they share?
What are antagonists?
This type of variation describes an unusual, unpredictable response seen in only a small proportion of individuals
What is an idiosyncratic response?
Calcium binds tetracycline in the gastrointestinal tract, reducing antibiotic absorption. This is what type of pharmacokinetic interaction?
What is an absorption interaction (chelation/complex formation)?
This developmental process occurs primarily between weeks 3–8 of pregnancy and represents the period of greatest susceptibility to major structural malformations.
What is organogenesis?
Dry mouth caused by anticholinergic medications is known by this medical term.
What is xerostomia?
A pharmaceutical company develops a monoclonal antibody tablet. Based on its pharmacokinetic properties, predict whether it is likely to be effective.
It is unlikely to be effective because proteins are digested by proteases in the GI tract and are therefore not orally bioavailable!
Name the four metabolizer phenotypes recognized in pharmacogenetics.
Poor, Intermediate, Normal, and Ultrarapid metabolizers
Drug metabolism slows, plasma drug concentration increases, and toxicity becomes more likely. This has occurred because of this CYP450 process.
What is enzyme inhibition?
Name two major factors that determine whether a drug will produce developmental toxicity.
What are dose, timing of exposure, biological susceptibility, or mechanism of action? (Any two.)
This OTC cough suppressant works centrally but does not act through opioid receptors.
What is dextromethorphan?
Natural antibodies can eliminate pathogens in many ways. Name TWO mechanisms discussed in lecture.
A patient is a CYP2D6 poor metabolizer. They receive an ACTIVE drug that is inactivated by CYP2D6. What happens to the parent drug concentration?
It increases, increasing the risk of adverse effects/toxicity!
This transporter pumps drugs out of cells, limits intestinal absorption, helps protect the brain, and promotes renal and biliary excretion.
What is P-glycoprotein (P-gp)?
A patient taking an antiseizure medication becomes pregnant and asks if she should immediately stop her medication. What is the most important principle that guides your recommendation?
What is the risk of the medication must be weighed against the risk of untreated maternal disease?
Histamine is primarily stored in these immune cells before being released during an allergic reaction.
What are mast cells?
A patient asks why loratadine is preferred over diphenhydramine during the day. Explain the answer using pharmacokinetic principles!
Loratadine poorly crosses the blood-brain barrier, so it causes much less sedation than diphenhydramine
A patient taking olanzapine starts smoking cigarettes. What happens to olanzapine concentration?
It decreases because cigarette smoke induces CYP1A2, increasing metabolism. (The inducer is the smoke, not the nicotine.)
Morphine and fentanyl produce a combined analgesic effect equal to the sum of each drug alone. This is what type of pharmacodynamic interaction?
What is additive?
Folic acid supplementation is recommended before conception because this developmental event occurs before many people realize they are pregnant.
What is closure of the neural tube?
This OTC medication removes warts by weakening the wart's attachment to the epidermis.
What is salicylic acid?
A patient taking a monoclonal antibody for migraine prevention is prescribed erythromycin, a CYP450 inhibitor. Should you expect a clinically important pharmacokinetic interaction? Why or why not?
No. Unlike many small-molecule drugs discussed in the drug interactions lecture, monoclonal antibodies are not metabolized by CYP450 enzymes, so CYP inhibition should not significantly alter their metabolism.
A mutation in the promoter region is most likely to affect this aspect of protein expression
Protein abundance (amount expressed), not protein structure
A new medication causes another drug's plasma concentration to increase within 24 hours. Is enzyme inhibition or enzyme induction more likely?
Enzyme inhibition, because inhibition develops quickly (hours to days), whereas induction develops slowly (days to weeks)
A drug has a milk-to-plasma ratio (M/P) greater than 1. Does this automatically mean it is unsafe during breastfeeding? Explain why or why not.
No. The M/P ratio alone does not determine infant safety because it does not account for maternal dose, the amount of milk consumed, or the actual infant exposure (relative infant dose, RID).
This OTC ingredient increases respiratory tract secretions to help loosen mucus, although evidence supporting its effectiveness is limited.
What is guaifenesin?