Pharmacology terms

54 terms

ACE inhibitors: A drug class that blocks the conversion of angiotensin I to angiotensin II, dilating blood vessels and reducing aldosterone; used for hypertension, heart failure and diabetic kidney disease. Watch for first-dose hypotension, a dry cough, hyperkalemia and rare but life-threatening angioedema; they are contraindicated in pregnancy. Monitor blood pressure, potassium and renal function.
Acetaminophen: A pain reliever and fever reducer that acts centrally and has little anti-inflammatory effect; unlike NSAIDs, it does not irritate the stomach or affect platelets. Overdose, including accidental overdose from several combination products, causes severe liver injury that may produce no symptoms for the first day; acetylcysteine is the antidote and works best when started early. Check every product the client takes for acetaminophen, stay within the ordered daily maximum, and take extra care with liver disease, regular alcohol use and malnutrition.
Adverse drug reaction: A harmful, unintended response to a drug given at a normal dose, distinct from an expected, usually mild side effect and from toxicity caused by overdose. Allergic reactions and anaphylaxis belong here. If you suspect one, stop the drug, assess the client, notify the prescriber and file a pharmacovigilance report.
Aminoglycosides: Antibiotics that block bacterial protein synthesis, used mainly for serious gram-negative infections (e.g., gentamicin, amikacin, tobramycin); they are poorly absorbed orally, so they are given IV or IM. Nephrotoxicity and ototoxicity, which can be permanent (hearing loss, tinnitus, vertigo), are the main risks, and they can cause neuromuscular blockade. Their therapeutic range is narrow, so peak and trough levels are monitored. Monitor creatinine, urine output and hearing, draw levels at the ordered times, and use caution with other nephrotoxic drugs.
Angiotensin II receptor blockers: A drug class that blocks angiotensin II from binding to its receptors in blood vessels and the adrenal glands (e.g., losartan, valsartan), dilating vessels and reducing aldosterone effects. They treat hypertension, heart failure and diabetic kidney disease, especially in clients who develop a cough on ACE inhibitors. Hypotension, hyperkalemia and worsening kidney function can occur; angioedema is rare. They harm the fetus and are not used in pregnancy. Monitor blood pressure, potassium and kidney function, and teach the client to avoid potassium-based salt substitutes.
Anticholinergic drugs: Drugs that block acetylcholine at muscarinic receptors (e.g., atropine, scopolamine, oxybutynin, ipratropium); used for symptomatic bradycardia, to dry secretions, and for overactive bladder, motion sickness and bronchospasm. Typical effects are dry mouth, blurred vision, tachycardia, constipation, urinary retention, reduced sweating with hyperthermia, and confusion or delirium, especially in older adults. Many other drugs, such as tricyclic antidepressants and first-generation antihistamines, add to the anticholinergic load. Monitor bowel and bladder function, heart rate and mental status.
Anticoagulants: Drugs that prevent clots from forming or growing: heparins, warfarin and direct oral anticoagulants. The main risk is bleeding: watch gums, urine, stool and bruising, and monitor aPTT or anti-Xa with unfractionated heparin, platelets with any heparin and INR with warfarin. Antidotes are protamine for heparin and vitamin K for warfarin. Teach clients on warfarin to keep their vitamin K intake consistent.
Antiemetics: Drugs that prevent or relieve nausea and vomiting through different pathways: serotonin 5-HT3 antagonists (e.g., ondansetron), dopamine antagonists (e.g., metoclopramide), antihistamines, NK1 antagonists and corticosteroids. The choice depends on the cause, such as chemotherapy, surgery, pregnancy or motion. Ondansetron can prolong the QT interval and cause constipation, dopamine antagonists can cause extrapyramidal symptoms, and many cause drowsiness. Give them before a predictable trigger such as chemotherapy, assess fluid and electrolyte status, and prevent falls in sedated clients.
Antiplatelet agents: A drug class that prevents arterial clots by stopping platelets from clumping: aspirin and P2Y12 inhibitors (e.g., clopidogrel, ticagrelor). They are used in acute coronary syndrome, after coronary stenting, and in ischemic stroke and peripheral artery disease. The main risk is bleeding, especially gastrointestinal bleeding. Stopping dual antiplatelet therapy after a stent without cardiology approval can cause stent thrombosis. Monitor for bleeding, check before surgery whether the drug was held as ordered, and teach adherence.
Antipsychotics: Drugs that reduce psychotic symptoms mainly by blocking dopamine receptors; divided into typical (first-generation, e.g., haloperidol) and atypical (second-generation, e.g., risperidone, olanzapine, clozapine). Typicals carry more extrapyramidal symptoms and tardive dyskinesia, atypicals more weight gain and metabolic syndrome. Neuroleptic malignant syndrome is an emergency, and clozapine needs blood count monitoring for agranulocytosis.
Antiseizure medications: Drugs that prevent seizures by reducing neuronal excitability (e.g., levetiracetam, valproate, carbamazepine, phenytoin, lamotrigine); benzodiazepines stop a prolonged seizure. Drowsiness and dizziness are common; some cause serious rashes, liver injury, blood disorders, birth defects or many interactions, several need blood levels checked, and all carry a risk of suicidal thoughts. Give them on schedule and never stop them abruptly, as seizures can follow. Take fall precautions; teach the client to report a rash or mood change at once and not to drive until cleared.
Benzodiazepines: A drug class that enhances GABA to produce anxiolytic, sedative, muscle-relaxant and anticonvulsant effects (e.g., lorazepam, diazepam, midazolam); used for anxiety, seizures and alcohol withdrawal. With opioids or alcohol they raise the risk of respiratory depression, and in older adults they can cause falls and confusion. Flumazenil is the reversal agent but can trigger seizures in long-term users. Dependence can develop, so long-term use is tapered.
Beta blockers: A drug class that blocks beta-1 receptors in the heart (nonselective agents also block beta-2), lowering heart rate, contractility and blood pressure; used for hypertension, angina, arrhythmias and heart failure. Check the apical pulse and blood pressure first, and hold and consult if they are below ordered parameters. They can mask signs of hypoglycemia, nonselective agents can trigger bronchospasm in asthma, and they must not be stopped abruptly.
Biguanides: An oral drug class that is usually first-line in type 2 diabetes; its only member in current use, metformin, lowers hepatic glucose production, improves insulin sensitivity and rarely causes hypoglycemia on its own. Nausea, diarrhea and a metallic taste are common at first, so it is taken with meals, and long-term use can lower vitamin B12. Lactic acidosis is rare but serious; kidney impairment, hypoxia, heavy alcohol use and dehydration raise the risk. Check kidney function, and hold the drug as ordered around iodinated contrast studies, surgery or acute illness.
Bioavailability: The fraction of a dose that reaches the systemic circulation unchanged. An IV drug has 100% bioavailability; oral drugs usually have less, because they must be absorbed and many are partly broken down by the liver before reaching the circulation (the first-pass effect). That is why oral and IV doses of the same drug can differ, and why sublingual, transdermal or rectal routes can bypass part of the first pass. Food, other drugs, and gut or liver disease change bioavailability, so give drugs as directed in relation to meals and never switch routes without an order.
Bronchodilators: Drugs that relax bronchial smooth muscle to open the airways: short- and long-acting beta-2 agonists (e.g., salbutamol, also called albuterol), anticholinergics (e.g., ipratropium, tiotropium) and theophylline. Short-acting agents relieve acute symptoms and long-acting ones are for maintenance. In asthma (GINA), a short-acting agent is not used as the only treatment, and a long-acting beta-2 agonist is never used alone, only with an inhaled corticosteroid. They can cause tachycardia, palpitations and tremor. Teach inhaler and spacer technique, and reassess breath sounds afterwards.
Calcium channel blockers: A drug class that blocks calcium entry into vascular smooth muscle and heart cells. Dihydropyridines (e.g., amlodipine) dilate arteries and can cause headache, flushing, ankle edema and reflex tachycardia. Nondihydropyridines (diltiazem, verapamil) also slow the heart rate and AV conduction and can cause bradycardia, heart block and constipation. They treat hypertension, angina and some arrhythmias. Check blood pressure and pulse before each dose, hold and consult if below ordered parameters, and teach the client to avoid grapefruit juice.
Cardiac glycosides: A drug class that strengthens myocardial contraction and slows the heart rate; the main example is digoxin, used in heart failure and atrial fibrillation. Its therapeutic range is narrow. Count the apical pulse for a full minute first and, in adults, usually hold the drug and consult if the rate is below 60/min. Hypokalemia increases toxicity; nausea, anorexia, yellow-green halos and new arrhythmias signal toxicity.
Cephalosporins: Beta-lactam antibiotics grouped into generations, with later generations more active against gram-negative bacteria (e.g., first-generation cefazolin, third-generation ceftriaxone). Cefazolin is widely used for surgical prophylaxis, given within the hour before incision. Cross-reactivity with penicillins is low, but consult the provider after a severe penicillin reaction. Diarrhea and Clostridioides difficile infection can occur. Never mix or co-infuse ceftriaxone with calcium-containing IV solutions, and avoid it in newborns who need them. Take an allergy history and monitor for anaphylaxis.
Corticosteroids: A drug class with strong anti-inflammatory and immunosuppressive effects (e.g., prednisolone, dexamethasone). They can cause hyperglycemia, masked signs of infection, fluid retention, peptic ulcers, bone loss and mood changes. After long-term use they suppress the adrenal glands, so they are tapered rather than stopped abruptly; monitor blood glucose and watch for infection.
Cytochrome P450 enzymes: A family of enzymes, mainly in the liver and gut, that metabolize many drugs (e.g., CYP3A4, CYP2D6). Enzyme inducers (e.g., rifampin, carbamazepine, St. John's wort) speed metabolism and can make other drugs fail; inhibitors (e.g., clarithromycin, fluconazole, grapefruit juice) slow it and can push other drugs to toxic levels. Genetic differences make some people fast or slow metabolizers. This underlies many serious interactions, for example with warfarin. Check every new drug, supplement and herbal product against the client's medication list, and report interactions.
Drug interaction: When the effect of a drug is increased or decreased by another drug, a food, an herbal product or alcohol. For example, grapefruit juice slows the metabolism of some drugs, and sudden changes in vitamin K-rich foods alter the effect of warfarin. Ask about every product the client takes, including herbal ones, and check an interaction reference.
GLP-1 receptor agonists: Injectable or oral drugs that mimic the gut hormone GLP-1 (e.g., liraglutide, semaglutide): they increase glucose-dependent insulin release, suppress glucagon, slow gastric emptying and reduce appetite. They treat type 2 diabetes, and some treat obesity. Nausea, vomiting and diarrhea are common; hypoglycemia is unlikely unless combined with insulin or a sulfonylurea. They are not used with a personal or family history of medullary thyroid cancer or MEN 2. Teach the client to report severe abdominal pain (pancreatitis) or persistent vomiting and to tell the anesthesia team before surgery.
Half-life: The time it takes for the plasma concentration of a drug to fall by half. It determines how often a drug is given: with regular dosing, steady state is reached after about 4–5 half-lives, and a stopped drug is largely eliminated over a similar period. It can lengthen in kidney or liver failure.
High-alert medications: Drugs that carry a heightened risk of significant harm when used in error, such as insulin, anticoagulants, opioids, concentrated electrolytes (e.g., potassium chloride), chemotherapy and neuromuscular blockers. Store them separately with warning labels, and use an independent double check by two clinicians when preparing and giving them.
Inhaled corticosteroids: Corticosteroids taken by inhalation to reduce airway inflammation (e.g., budesonide, fluticasone, beclomethasone); they are controller medicines in asthma and in some clients with COPD, and do not relieve an acute attack. GINA recommends that treatment for adults and adolescents with asthma contain an inhaled corticosteroid. Oral thrush and hoarseness are the most common adverse effects. Teach regular use, correct inhaler technique and a spacer when needed, and have the client rinse the mouth and spit after each use.
Insulin therapy: The hormone made by pancreatic beta cells that lets glucose enter cells; as a drug it comes in rapid-, short-, intermediate- and long-acting types. It is life-sustaining in type 1 diabetes. Its main risk is hypoglycemia: monitor blood glucose, time meals to the insulin's action and use a double check when giving it. Regular insulin is the type generally used for IV infusion.
Laxatives: Drugs that promote bowel movements: bulk-forming agents (e.g., psyllium), osmotic agents (e.g., lactulose, polyethylene glycol), stimulants (e.g., senna, bisacodyl) and stool softeners (docusate). They prevent and treat constipation, for example during opioid therapy, and prepare the bowel for procedures. Bulk formers need plenty of fluid to avoid obstruction; overuse can cause dehydration, electrolyte imbalance and dependence. They are not given when bowel obstruction is suspected or for acute abdominal pain. Assess bowel pattern, abdomen and fluid intake; teach fiber, fluids and activity.
Leukotriene receptor antagonists: Oral drugs that block receptors for leukotrienes, which cause bronchoconstriction, mucus and inflammation (e.g., montelukast); used as add-on controllers in asthma, for exercise-induced bronchospasm and, when other treatments fail, for allergic rhinitis, not for an acute attack. Serious neuropsychiatric effects such as agitation, sleep disturbance, depression and suicidal thinking have been reported. Teach daily use and keeping a rescue inhaler at hand, and ask the client and family to report mood or behavior changes at once.
Loop diuretics: A drug class that blocks sodium and chloride reabsorption in the loop of Henle, producing strong diuresis (e.g., furosemide); used for edema, heart failure and acute pulmonary edema. Watch for hypokalemia, hyponatremia, dehydration, hypotension and ototoxicity with rapid IV injection. Monitor intake and output, daily weight, electrolytes and blood pressure.
Mood stabilizers: Drugs that prevent manic and depressive episodes in bipolar disorder: lithium and antiepileptics such as valproate, carbamazepine and lamotrigine. Lithium has a narrow therapeutic range, so blood levels and renal and thyroid function are monitored. Dehydration and low salt intake raise lithium levels; nausea, diarrhea, coarse tremor, ataxia and confusion signal toxicity. Valproate and carbamazepine are teratogenic.
Nitrates: A drug class that dilates veins and coronary arteries, reducing preload and myocardial oxygen demand (e.g., nitroglycerin, isosorbide mononitrate); used to treat and prevent angina. Headache, flushing, dizziness and hypotension are common. Taken with phosphodiesterase-5 inhibitors (e.g., sildenafil) they cause severe hypotension, so ask about these drugs. Have the client sit before taking sublingual nitroglycerin, and teach them to call emergency services if pain persists 5 minutes after the first dose. Patches and long-acting forms need a nitrate-free interval to prevent tolerance.
Nonsteroidal anti-inflammatory drugs: A drug class that inhibits cyclooxygenase (COX) enzymes and reduces prostaglandin production, relieving pain, fever and inflammation (e.g., ibuprofen, naproxen). They raise the risk of GI bleeding and ulcers, kidney injury, fluid retention and cardiovascular events. Give them with food, and use them cautiously in older adults, in kidney disease and with anticoagulants.
Opioid analgesics: Drugs that bind opioid receptors in the central nervous system to relieve moderate to severe pain (e.g., morphine, fentanyl, oxycodone). The most dangerous effect is respiratory depression, which is usually preceded by increasing sedation, so assess sedation level along with respiratory rate. Constipation, nausea and itching are common. Naloxone reverses them; keep monitoring, because it can wear off before the opioid does.
Opioid antagonists: Drugs that displace opioids from their receptors and reverse their effects; naloxone, given IV, IM, subcutaneously or intranasally, reverses opioid-induced respiratory depression within minutes. Its effect can wear off before a long-acting opioid's, so respiratory depression can return: keep monitoring respiratory rate, oxygen saturation and sedation level after it is given. In clients who take opioids regularly, rapid reversal can cause acute withdrawal and severe pain, so titrate as ordered. Keep naloxone available wherever opioids are given.
Patient-controlled analgesia: A programmable infusion pump that lets the client give themselves small preset doses of an analgesic, usually an opioid, by pressing a button, within a lockout interval and dose limits set by the prescriber; it gives steadier pain control and a sense of control. Only the client may press the button: family members or staff pressing it (PCA by proxy) can cause oversedation. Assess pain, sedation level, respiratory rate and oxygen saturation regularly, have a second nurse check the pump settings, keep naloxone available, and teach the client how to use it.
Peak and trough levels: The highest (peak) blood concentration of a drug and the lowest (trough) level just before the next dose. They are measured for narrow-range drugs such as aminoglycosides to check effectiveness and avoid toxicity; vancomycin is increasingly monitored by area under the curve (AUC) instead. Draw the trough just before the next dose and record the exact sampling time.
Penicillins: Beta-lactam antibiotics that block bacterial cell wall synthesis (e.g., amoxicillin, ampicillin, piperacillin-tazobactam), used against many gram-positive and some gram-negative infections. Allergic reactions range from rash to anaphylaxis and are more likely after a previous penicillin reaction. Ask about allergies before the first dose, observe the client for anaphylaxis after it, and keep emergency treatment at hand. Diarrhea and Clostridioides difficile infection can occur; teach the client to complete the full course.
Pharmacodynamics: What a drug does to the body: how it produces its effects, mostly by binding to receptors, enzymes or ion channels. An agonist activates a receptor, an antagonist blocks it, and a partial agonist produces a weaker effect. Potency, efficacy and the dose-response relationship describe how much drug is needed and how large an effect it can produce; tolerance is a smaller response with repeated use. Together with pharmacokinetics, it explains why the same drug affects people differently. Assess the expected therapeutic effect and the adverse effects of every drug you give.
Pharmacokinetics: What the body does to a drug: absorption, distribution, metabolism (mostly in the liver) and excretion (mostly by the kidneys). These processes change in older adults, children and clients with liver or kidney impairment, so drugs can accumulate to toxic levels; monitor renal and hepatic function.
Polypharmacy: The concurrent use of many medications. In older adults it raises the risk of falls, confusion, drug interactions and adverse reactions. Build a complete medication list, including over-the-counter and herbal products, consider criteria for potentially inappropriate drugs in older adults (e.g., Beers), and review unnecessary drugs with the prescriber.
Potassium-sparing diuretics: Weak diuretics that increase sodium excretion in the distal nephron while retaining potassium: aldosterone antagonists (spironolactone, eplerenone) and epithelial sodium channel blockers (amiloride, triamterene). They are used in heart failure, ascites from cirrhosis, primary hyperaldosteronism and resistant hypertension. The main danger is hyperkalemia, more likely with ACE inhibitors, ARBs or kidney failure; spironolactone can cause gynecomastia. Monitor potassium and kidney function, and teach the client to avoid potassium supplements and potassium-based salt substitutes.
Proton pump inhibitors: Drugs that block the final step of acid secretion in the gastric parietal cells (e.g., omeprazole, pantoprazole); used for gastroesophageal reflux, peptic ulcer, H. pylori eradication with antibiotics, stress ulcer prevention and stomach protection during NSAID therapy. Oral forms work best taken before breakfast. Use, especially long-term, is linked to Clostridioides difficile infection, pneumonia, low magnesium, vitamin B12 deficiency and fractures, so the continued need should be reviewed. Teach the client to swallow delayed-release forms whole and to report black stools.
Rights of medication administration: Checks made for every dose so medications are given safely: right client, right drug, right dose, right route and right time, often extended with right documentation, right reason and the right to refuse. Repeat the checks while preparing the drug and again at the bedside. The rights reduce errors but do not replace system-level safeguards.
Selective serotonin reuptake inhibitors: A class of antidepressants that blocks serotonin reuptake at the synapse (e.g., sertraline, fluoxetine, escitalopram); widely used for depression and anxiety disorders. The full effect takes several weeks. Monitor closely early in treatment, especially in young people, as suicidal thinking can increase. Combining them with other serotonergic drugs risks serotonin syndrome, and they should not be stopped abruptly.
Serotonin syndrome: A potentially life-threatening reaction to serotonergic drugs (such as SSRIs, SNRIs, MAO inhibitors, tramadol and triptans), most often when they are combined but also with one drug alone, especially when it is started or its dose is increased. Signs include agitation or confusion, tachycardia, hyperthermia, sweating, diarrhea, tremor, clonus and hyperreflexia. Hold the suspected drug, notify the prescriber and monitor vital signs and temperature closely.
SGLT2 inhibitors: Oral drugs that make the kidneys excrete glucose and sodium in the urine (e.g., empagliflozin, dapagliflozin); besides lowering glucose in type 2 diabetes, they protect the heart and kidneys and are also used in heart failure and chronic kidney disease. Genital fungal infections, urinary tract infections, volume depletion and hypotension can occur. They can cause ketoacidosis with near-normal glucose (euglycemic DKA), especially during acute illness, fasting or surgery. Teach genital hygiene and adequate fluid intake, and hold the drug as ordered during acute illness and before surgery.
Statins: A drug class that inhibits HMG-CoA reductase, reducing cholesterol synthesis in the liver and lowering LDL cholesterol (e.g., atorvastatin, rosuvastatin); they reduce cardiovascular risk in coronary artery disease, stroke and diabetes. The key adverse effects are myopathy and, rarely, rhabdomyolysis; liver enzymes can rise. They are not used in pregnancy. Teach the client to report unexplained muscle pain, weakness or dark urine at once, that some statins interact with grapefruit juice, and that diet and exercise remain part of treatment.
Sulfonylureas: Oral drugs for type 2 diabetes that make pancreatic beta cells release insulin regardless of the blood glucose level (e.g., glipizide, glimepiride, gliclazide). Hypoglycemia is the main risk, especially in older adults, in kidney impairment and when meals are skipped or delayed, and it can be prolonged. Weight gain is common. Teach the client to take the drug with or just before a meal, never to skip meals, to recognize and treat hypoglycemia, and to check blood glucose as advised; beta blockers can mask the warning signs.
Therapeutic index: The ratio between the toxic dose and the effective dose of a drug. With a narrow therapeutic index (e.g., digoxin, lithium, warfarin, aminoglycosides) effective and toxic levels lie close together, so monitor blood levels and signs of toxicity and watch for drug interactions.
Thiazide diuretics: A class of moderate-strength diuretics that block sodium and chloride reabsorption in the distal tubule (e.g., hydrochlorothiazide, indapamide); a common first-line treatment for hypertension. They can cause hypokalemia, hyponatremia, hypercalcemia, hyperglycemia and raised uric acid (gout attacks), and they work less well when kidney function is very low. Monitor blood pressure, electrolytes, blood glucose and daily weight; teach the client to take the drug in the morning to avoid nocturia and to report signs of hypokalemia.
Thrombolytics: Drugs that dissolve existing clots by converting plasminogen to plasmin (e.g., alteplase, tenecteplase). They are used in acute ischemic stroke within the treatment window, in STEMI when timely percutaneous coronary intervention is not available, and in massive pulmonary embolism. The gravest risk is major bleeding, including intracranial hemorrhage. Verify eligibility and exclusion criteria with a checklist, keep blood pressure below the ordered limit, perform frequent neurological checks, avoid unnecessary punctures and IM injections afterward, and watch for bleeding and angioedema.
Vancomycin: A glycopeptide antibiotic that inhibits cell wall synthesis in gram-positive bacteria; given IV for resistant gram-positive infections, including MRSA, and orally for Clostridioides difficile infection. Infusing it too fast causes an infusion reaction with flushing of the face, neck and trunk, itching and hypotension, so it is infused over at least 60 minutes. It can cause nephrotoxicity and ototoxicity, and blood levels are monitored. Follow the ordered infusion rate, monitor creatinine and urine output, and draw levels at the ordered times.
Vasopressors and inotropes: High-alert drugs that support perfusion in shock: vasopressors (e.g., norepinephrine, epinephrine, vasopressin) constrict vessels to raise blood pressure, and inotropes (e.g., dobutamine) strengthen cardiac contraction. Hypovolemia is corrected first; they are given as a continuous infusion by pump, preferably through a central line, and titrated to the ordered mean arterial pressure. Monitor blood pressure continuously, plus heart rate, rhythm, urine output and limb perfusion, and check the infusion site often, because extravasation can cause tissue necrosis.