Pharmacotherapeutic Principles
This “M” in ADME refers to how the body chemically alters drugs, usually in the liver.
What is Metabolism?
You’re starting a new antihypertensive drug in a patient. Before it ever reaches your clinic, the FDA required small studies in healthy volunteers to test safety and how the body processes the drug. This describes this trial phase.
What is Phase I?
A patient on chemotherapy asks why they are losing their hair and feeling so tired. You explain that these side effects happen because chemotherapy targets not only cancer cells but also these types of normal cells.
What are rapidly dividing cells (like hair follicles and bone marrow)?
A 5-year-old with strep throat needs treatment. The child has a history of a mild penicillin rash. The best alternative is this antibiotic class.
What are macrolides (e.g., azithromycin)?
A patient with glaucoma is prescribed timolol drops but has a history of COPD. You decide against this therapy because timolol can worsen this underlying condition.
What are respiratory diseases (bronchospasm in COPD/asthma)?
A patient with rheumatoid arthritis on prednisone wants to stop the medication abruptly because their joints feel better. You explain they must taper slowly to avoid this dangerous complication.
What is adrenal crisis (from adrenal suppression)?
Because oral drugs pass through the liver before reaching circulation, they may require larger doses compared to IV drugs. This phenomenon is called ____.
What is the First-pass effect?
A 32-year-old patient with heroin use disorder asks if you can prescribe heroin for withdrawal symptoms. You explain that heroin is classified in this DEA schedule, which means it cannot be prescribed.
What is Schedule I?
Your patient is receiving 5-FU for colon cancer. Their blood counts show ANC < 500, and they develop a fever. This complication is most concerning because of chemotherapy’s effect on this organ system.
What is bone marrow suppression (neutropenia/infection risk)?
A 72-year-old on chronic prednisone for COPD is prescribed levofloxacin for pneumonia. He reports new Achilles tendon pain after a few doses. This adverse effect is linked to this antimicrobial class.
What are fluoroquinolones?
A patient with glaucoma struggles to remember multiple daily eye drops. You switch them to latanoprost because this drug has strong efficacy and the convenience of this dosing schedule.
hat is once-daily dosing?
A 68-year-old with knee osteoarthritis takes ibuprofen daily. He reports new black stools. This complication is most likely due to NSAIDs reducing this protective factor in the stomach.
What are prostaglandins (leading to GI bleeding/ulcers)?
A malnourished patient on warfarin shows a rapid rise in INR after a small dose increase. This dosing principle explains why highly protein-bound drugs often require lower starting doses in hypoalbuminemia.
What is reduced protein binding increases free drug and effect (so start low/go slow)?
You are prescribing warfarin to a patient with multiple comorbidities and low income. To improve adherence, you choose the generic version. This is an example of this prescribing principle.
What is rational drug selection (balancing safety, efficacy, and cost)?
A breast cancer patient is prescribed trastuzumab. You order an echocardiogram before starting therapy to monitor for this specific toxicity.
What is cardiotoxicity (heart failure risk)?
Your patient develops severe diarrhea after completing clindamycin for a dental infection. You suspect this dangerous complication.
What is C. difficile colitis?
A swimmer presents with ear pain and drainage. You prescribe ciprofloxacin + hydrocortisone drops. The patient asks if it’s okay to use them with a ruptured eardrum. Your answer is no, because drops in this situation carry this risk.
What is ototoxicity (leading to hearing loss)?
A patient on long-term corticosteroids for lupus fractures their wrist after a minor fall. This adverse effect is linked to corticosteroids’ impact on this system.
What is the skeletal system (osteoporosis)?
A medication has a half-life of 6 hours. If the concentration is 100 mg/L at noon, the expected concentration at midnight is this.
What is 25 mg/L?
While reviewing a new seizure medication, you see the study included 500 patients with epilepsy, compared the drug to the current standard, and tracked side effects. This places it in this FDA trial phase.
What is Phase III?
A patient receiving chemotherapy for lymphoma reports new fatigue and shortness of breath. Labs show hemoglobin of 7.8 g/dL. This side effect is most likely due to chemotherapy’s effect on this bone marrow cell line.
What are red blood cells (leading to anemia)?
A patient with MRSA bacteremia is started on vancomycin. After 2 weeks, creatinine levels rise and hearing loss develops. These toxicities are classic for vancomycin’s effects on these two organ systems.
What are the kidneys (nephrotoxicity) and ears (ototoxicity)?
A 3-year-old with acute otitis media has been on amoxicillin for 3 days with no improvement. According to guidelines, the next best antibiotic choice is this.
What is amoxicillin-clavulanate (or ceftriaxone)?
Before starting adalimumab for Crohn’s disease, you screen your patient for tuberculosis and hepatitis B. The rationale is that immune modulators increase this type of risk.
What is infection risk (reactivation of latent infections)?
A patient drinks grapefruit juice daily while taking simvastatin. They develop severe muscle pain. This happened because grapefruit juice did this to simvastatin metabolism.
What is inhibited it (leading to higher drug levels and toxicity)?
An APRN in New York can prescribe independently, but her colleague in Florida must have physician collaboration. This difference reflects a key variation in this aspect of APRN practice.
What is prescriptive authority by state law?
A patient on vincristine reports tingling and numbness in their hands and feet, making it hard to button clothes. This side effect happens because vincristine disrupts this cellular structure.
What is disruption of microtubule function (leading to peripheral neuropathy)?
A woman being treated for latent tuberculosis with rifampin becomes pregnant unexpectedly while on oral contraceptives. You explain the pregnancy occurred because rifampin had this effect on her birth control.
What is induced metabolism (CYP450 induction → reduced contraceptive efficacy)?
Parents report that their child screams when they give antibiotic ear drops for otitis externa. You teach them this simple step before administration to reduce discomfort and dizziness.
What is warming the drops in the hand before instilling them?
A patient with psoriasis is well controlled on a biologic therapy but develops recurrent sinus infections. This side effect occurs because biologics work by blocking these immune system signals.
What are cytokines (e.g., TNF, interleukins)?