One mechanism, then everything that follows.
Each class below starts with what the drug does to a receptor or an enzyme, then derives the uses, the side effects and the contraindications from it. The handful of facts that genuinely cannot be derived are flagged separately, so you know what to reason out and what to memorise.
Why the class is the right unit
Studying drug by drug produces a list that grows faster than anyone can hold it, and it leaves you helpless in front of a generic name you have not specifically revised. Studying by class inverts that. A beta blocker you have never seen is already three quarters explained by the word beta blocker, and what remains is a short set of exceptions worth knowing precisely because they are exceptions.
That is also how the examiners think. Questions rarely ask what a drug is; they describe a patient and ask what happens next, which is a question about the class far more often than about the molecule.
Cardiovascular
Beta blockers
Beta blockers occupy beta-adrenergic receptors so that circulating adrenaline and noradrenaline cannot act on them.
Open class →-prilACE inhibitors
ACE inhibitors block angiotensin converting enzyme, which both reduces angiotensin II production and prevents bradykinin breakdown.
Open class →-statinStatins
Statins inhibit HMG-CoA reductase, the rate-limiting enzyme of cholesterol synthesis in the liver.
Open class →Mixed stemsAnticoagulants
Anticoagulants interrupt the clotting cascade at different points, and where a drug acts determines how fast it works, how it is monitored and how it is reversed.
Open class →Mixed stemsDiuretics
Diuretics block sodium reabsorption at a specific segment of the nephron, and the segment determines both the potency and the electrolyte side effects.
Open class →Central nervous system
Opioids
Opioids activate mu receptors, reducing neuronal excitability and neurotransmitter release along pain pathways and everywhere else those receptors appear.
Open class →-azepam, -azolamBenzodiazepines
Benzodiazepines increase the frequency of chloride channel opening at the GABA-A receptor, amplifying inhibition that GABA itself must initiate.
Open class →Mixed stemsSSRIs
SSRIs block the presynaptic serotonin transporter, leaving more serotonin in the synapse for longer.
Open class →How to use these alongside everything else
Read the class first, then test yourself on it. Understanding a mechanism and being able to retrieve it under time are different skills, and only the second one is examined, so pair each class with its free practice questions rather than reading twice. If your problem is method rather than content, how to study pharmacology sets out what the evidence actually supports, and the blog goes deeper on individual mechanisms than a class page can. Where two members of a class are easy to confuse, the side-by-side drug comparisons split them on the one property that actually separates them, and the regional study guides cover which names and formularies apply where you are training.
Common questions
What is the fastest way to learn a drug class?
Learn what the class does to a receptor or an enzyme, then derive the side effects from it rather than learning them as a second list. Most adverse effects are the intended action of the drug appearing in a tissue where it was not wanted, which means one mechanism can replace a page of memorised facts.
Why learn by class instead of by individual drug?
Because exams and practice both present drugs you have never specifically revised. A class gives you a default: if you know what beta blockade does, an unfamiliar drug ending in -olol is already most of the way explained. Individual drugs then become exceptions to a rule you already hold.
Which drug classes are highest yield?
The cardiovascular classes carry more of a typical pharmacology paper than any other system, and the autonomic groundwork underneath them explains a large share of everything else. Beta blockers, ACE inhibitors and the anticoagulants repay study first.
Do side effects really follow from the mechanism?
Most do, and on each page below they are written that way. A few genuinely do not, such as the rebound risk on stopping a beta blocker abruptly, and those are flagged separately as things that have to be learned outright rather than reasoned out.
Study aid only. These pages are written for learning and examination practice. They are not medical advice, not clinical decision support, and must never be used to make a decision about a real patient. Always verify against your local formulary, the product literature and a qualified pharmacist. See our medical disclaimer.
Learn the class once, recognise every member.
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