Review this high-yield breakdown of primary care drug classes, mechanisms, and strict contraindications. Print or save this reference to master pharmacology, then test your knowledge with our 3030 practice questions.
Hypertension & Heart Failure
ACE Inhibitors (-pril) — Block conversion of angiotensin I to II / First-line for HTN with diabetes or CKD / Contraindicated in pregnancy and bilateral renal artery stenosis.
ARBs (-sartan) — Block angiotensin II receptors / Used when ACE inhibitors cause dry cough / Contraindicated in pregnancy.
Thiazide Diuretics (hydrochlorothiazide, chlorthalidone) — Inhibit sodium reabsorption in distal tubule / First-line for uncomplicated HTN / Contraindicated with sulfa allergy or severe gout.
Calcium Channel Blockers (Dihydropyridines: -dipine) — Relax vascular smooth muscle / First-line for African American patients with HTN / Watch for peripheral edema.
Beta Blockers (-olol) — Block sympathetic stimulation / Post-MI or heart failure use, not first-line for primary HTN / Avoid non-selective beta blockers in asthma or COPD.
Type 2 Diabetes Mellitus
Biguanides (Metformin) — Decrease hepatic glucose production / First-line for T2DM / Contraindicated in severe renal impairment (eGFR < 30) due to lactic acidosis risk.
SGLT2 Inhibitors (-gliflozin) — Increase urinary glucose excretion / Cardioprotective and renoprotective / Risk of genital mycotic infections and euglycemic diabetic ketoacidosis.
GLP-1 Receptor Agonists (-tide) — Stimulate insulin release and delay gastric emptying / High efficacy for weight loss and cardioprotection / Contraindicated with personal or family history of medullary thyroid carcinoma.
Sulfonylureas (glipizide, glimepiride) — Stimulate pancreatic beta cells to release insulin / High risk of hypoglycemia and weight gain / Avoid in elderly patients (Beers Criteria).
DPP-4 Inhibitors (-gliptin) — Prolong action of incretin hormones / Weight neutral / Risk of joint pain and rare acute pancreatitis.
Dyslipidemia & Cardiovascular
Statins (HMG-CoA reductase inhibitors) — Decrease cholesterol synthesis in liver / First-line for hyperlipidemia and ASCVD risk reduction / Risk of myopathy and elevated liver enzymes; avoid in pregnancy.
Fibrates (fenofibrate, gemfibrozil) — Decrease triglyceride production / Used for severe hypertriglyceridemia to prevent pancreatitis / Increases myopathy risk if combined with statins.
Bile Acid Sequestrants (cholestyramine) — Bind bile acids in intestine / Safe in pregnancy / Can impair absorption of other fat-soluble vitamins and drugs.
Asthma & COPD
SABAs (Albuterol) — Short-acting beta-2 agonists / Rescue inhaler for acute bronchospasm / Overuse indicates poor asthma control.
ICS (Inhaled Corticosteroids: fluticasone, budesonide) — Reduce airway inflammation / First-line daily maintenance for persistent asthma / Rinse mouth after use to prevent oral thrush.
LABAs (salmeterol, formoterol) — Long-acting beta-2 agonists / Maintenance for COPD and asthma / Must always be combined with an ICS in asthma (never used as monotherapy due to mortality risk).
LAMAs (tiotropium) — Long-acting muscarinic antagonists / First-line maintenance for symptomatic COPD / Anticholinergic side effects include dry mouth and urinary retention.
Antibiotics (Key Classes)
Penicillins (amoxicillin) — Inhibit bacterial cell wall synthesis / First-line for acute otitis media and strep pharyngitis / Cross-reactivity risk with cephalosporins.
Macrolides (azithromycin) — Inhibit protein synthesis (50S subunit) / Used for atypical pneumonia or chlamydia / Risk of QT prolongation and GI upset.
Tetracyclines (doxycycline) — Inhibit protein synthesis (30S subunit) / First-line for Lyme disease and Rocky Mountain spotted fever / Contraindicated in pregnancy and children under 8 (tooth discoloration).
Fluoroquinolones (ciprofloxacin, levofloxacin) — Inhibit DNA gyrase / Used for complicated UTIs or severe pneumonia / Black box warning for tendon rupture; avoid in pregnancy.
Sulfonamides (TMP-SMX) — Inhibit folic acid synthesis / First-line for uncomplicated UTI or MRSA skin infections / Contraindicated in sulfa allergy, pregnancy (near term), and G6PD deficiency.
Women's Health & Bone Density
Combined Oral Contraceptives (Estrogen/Progestin) — Suppress ovulation / Regulate menses and reduce dysmenorrhea / Contraindicated in women over 35 who smoke, history of DVT/PE, or migraine with aura.
Progestin-Only Pills (Norethindrone) — Thicken cervical mucus / Safe during lactation and for women with estrogen contraindications / Must be taken at the exact same time daily.
Bisphosphonates (alendronate) — Inhibit osteoclast bone resorption / First-line for osteoporosis / Take on an empty stomach with water and remain upright for 30 minutes to prevent esophagitis.
Mental Health (Antidepressants)
SSRIs (sertraline, escitalopram) — Inhibit serotonin reuptake / First-line for depression and anxiety / Risk of sexual dysfunction, weight gain, and serotonin syndrome.
SNRIs (venlafaxine, duloxetine) — Inhibit serotonin and norepinephrine reuptake / Useful for depression with comorbid neuropathic pain / Can cause dose-dependent increases in blood pressure.
TCAs (amitriptyline) — Inhibit reuptake of serotonin and norepinephrine / Used off-label for migraine prophylaxis and neuropathy / High risk of fatal overdose (cardiac arrhythmias) and anticholinergic effects.
Atypical Antidepressants (bupropion) — Inhibit dopamine and norepinephrine reuptake / Used for depression and smoking cessation / Low risk of sexual dysfunction; contraindicated in seizure disorders or eating disorders.
