Pharmacology Review

A set of Q&A flashcards covering pharmacology basics, drug absorption/metabolism, safety, key drug classes, interactions, monitoring, and prescribing considerations from the lecture.

What is pharmacology?

The study of the interaction between the body and drugs.

What processes are included in pharmacokinetics (PK)?

Absorption, bioavailability, distribution, metabolism, and excretion.

What is pharmacodynamics (PD) the study of?

The physiologic and biochemical effects of drugs (what a drug does to the body).

What is pharmacogenomics?

The study of how a person’s genes affect response to medications; pharmacogenetics refers to individual genes, pharmacogenomics to populations.

Why is genotyping HLA-B*1502 relevant before starting carbamazepine?

It helps prevent severe Stevens–Johnson syndrome in certain Asian populations. FDA recommends genotyping Asians prior to carbamazepine therapy.

What does half-life (t½) refer to?

The amount of time in which drug concentration decreases by 50%.

What does AUC stand for and indicate?

Area Under the Curve; a measure of the average amount of drug in the blood after a dose (bioavailability).

What does Cmax mean?

The peak serum concentration of a drug.

What does MIC stand for in antibiotics?

Minimum Inhibitory Concentration—the lowest drug concentration that inhibits bacterial growth.

What is the concept of the first-pass effect?

Oral drugs are metabolized in the liver (CYP450) after absorption; some are too extensively metabolized to be given orally. Bypassed by IV, transdermal, vaginal, etc.

Which organ is the main site of drug metabolism?

The liver, with CYP450 enzymes being the primary system; six isozymes (CYP1A2, 2C9, 2C19, 2D6, 2E1, 3A4) handle most metabolism.

What can CYP450 induction do to drug levels?

Increase drug metabolism, potentially lowering drug concentration.

What can CYP450 inhibition do to drug levels?

Decrease drug clearance, increasing drug concentration and risk of toxicity.

Which antibiotic class includes strong CYP450 inhibitors like erythromycin and ketoconazole?

Macrolides and antifungals (among others) are potent CYP450 inhibitors.

Name some other CYP450 inhibitors mentioned.

Cimetidine; citalopram; protease inhibitors; certain antipsychotics; grapefruit juice (affects several CYP enzymes).

Why is grapefruit juice clinically important?

It inhibits CYP450 enzymes and can raise levels of drugs such as statins, macrolides, CCBs, antivirals, amiodarone, benzodiazepines, and others.

List some drugs with a narrow therapeutic index (NTI).

Warfarin; Digoxin; Theophylline; Carbamazepine; Phenytoin; Levothyroxine (TSH); Lithium.

What is Beers Criteria useful for?

Guidance on medications to avoid or adjust in adults over 65 years old.

Give examples of Beers Criteria 2020 focus areas.

Avoiding certain antipsychotics in elderly; higher bleeding risk with rivaroxaban and dabigatran vs warfarin/DOACs; tramadol hyponatremia risk; avoid combining opioids with benzodiazepines or gabapentinoids; avoid certain CNS depressants in older adults.

What are common drug considerations for patients with kidney disease?

Drugs may be nephrotoxic or require dose adjustment; NSAIDs reduce renal blood flow; ACEIs/ARBs risk hyperkalemia; warfarin/INR changes; lithium renal risk; contrast dyes; potassium-sparing diuretics; oral sodium phosphate; H2 blockers; PPIs.

How do NSAIDs generally affect the kidneys and heart failure?

NSAIDs can reduce renal perfusion and should be avoided in heart failure and severe renal disease; caution in GI bleed risk and late pregnancy.

What monitoring is advised with ACE inhibitors and ARBs?

Serum potassium and serum creatinine at baseline, within the first month, and periodically, especially in elderly, diabetics, and CKD.

What suffixes identify ACE inhibitors and ARBs?

ACE inhibitors end with -pril (e.g., lisinopril); ARBs end with -sartan (e.g., losartan).

What is a key adverse effect of ACE inhibitors, including a warning symptom?

ACE inhibitors can cause an annoying dry cough; they can also cause angioedema and are contraindicated in pregnancy.

What is a major clinical use distinction between ACE inhibitors and ARBs?

ACE inhibitors are first-line for HF with reduced ejection fraction and renal protection in diabetics; ARBs are alternatives when ACE inhibitors cause cough or angioedema or are not tolerated.

What is a boxed warning associated with neprilysin inhibitors combined with valsartan (Entresto)?

Fetal toxicity; contraindicated with ACE inhibitors and in patients with a history of angioedema.

What are common calcium channel blocker (CCB) subclasses and names?

Dihydropyridines: amlodipine, nifedipine, felodipine, nicardipine, isradipine; Non-dihydropyridines: verapamil, diltiazem.

What are key cautions with nondihydropyridine CCBs like verapamil and diltiazem?

Can worsen HFrEF; avoid in HFrEF; may cause bradycardia and constipation; interactions with certain antibiotics (e.g., macrolides).

What are common adverse effects of dihydropyridine CCBs?

Peripheral edema, headaches, flushing, dizziness; reflex tachycardia possible.

What are common adverse effects of nondihydropyridine CCBs?

Bradycardia, constipation, decreased cardiac output; can worsen HF with reduced EF.

Which beta-blockers are contraindicated in chronic lung disease?

Many nonselective agents; caution with asthma/COPD; avoid abrupt stopping due to rebound HTN.

What are alpha-blockers used for and what is a key side effect?

Used for BPH; some (terazosin, doxazosin) also lower BP; main side effect is orthostatic hypotension.

Which PDE5 inhibitors are contraindicated with nitrates?

Sildenafil, tadalafil, vardenafil should not be used with nitrates due to risk of severe hypotension.

What is a common safety note for Statins when taken with grapefruit juice?

Grapefruit juice can increase statin levels and risk of adverse effects like myopathy; avoid with certain statins.

What is the typical target INR for atrial fibrillation or DVT/PE without mechanical valves?

2.0 to 3.0 (ideal around 2.5).

What is the target INR for mechanical heart valves (mitral) or higher-risk situations?

2.5 to 3.5 (ideal around 3.0).

What are reversal agents for direct oral anticoagulants (DOACs)?

Idarucizumab (Praxbind) for dabigatran; andexanet alfa (Andexxa, Ondexxya) for FXa inhibitors (rivaroxaban, apixaban, edoxaban).

Which anticoagulants are DOACs and what is a key advantage over warfarin?

Direct Oral Anticoagulants: dabigatran, rivaroxaban, apixaban, edoxaban (and betrixaban); fixed dosing with fewer interactions and no routine INR monitoring.

When is warfarin still the preferred anticoagulant?

In patients with valvular disease or prosthetic heart valves requiring long-term anticoagulation.

What is commonly noted with clopidogrel regarding reversal?

There is no specific reversal agent; in some cases, FFP or cryoprecipitate may be used, but data are limited.

What are the Five Rights of medication safety?

Right patient, Right drug, Right dose, Right time, Right route.

What is e-prescribing and its main benefit?

Electronic prescribing; includes formulary information and helps streamline choosing appropriate medications.

What should be included on a prescription pad for controlled substances?

DEA number with clinic address; cannot be predated or postdated; date, patient name, drug, dose, route, frequency, and duration.

What is the PLLR in FDA labeling?

Pregnancy and Lactation Labeling Rule; replaced old letter categories with Pregnancy, Lactation, and Females/Males of Reproductive Potential information.

Which antibiotic class is commonly associated with C. difficile risk and is often used for penicillin-allergic patients?

Lincosamides (clindamycin).

What is the general guideline for antibiotic use in pregnancy for UTIs?

Beta-lactams, nitrofurantoin, and fosfomycin are commonly used options; avoid unnecessary antibiotics and consider safety profiles.

What is the main warning with fluoroquinolones (quinolones)?

Increased risk of Achilles tendon rupture, possible aortic dissection; boxed warnings; avoid in children and certain at-risk adults; QT prolongation risk; interactions with cations and other QT-prolonging drugs.

Which drugs are commonly monitored for thyroid, kidney, or hepatic effects due to narrow therapeutic windows?

Warfarin (INR), Digoxin (drug level), Theophylline (drug level), Lithium (drug level and TSH).