Med Drug Classes Cardiovascular Anti Infective And Analgesia

---
name: med-drug-classes-cardiovascular-anti-infective-and-analgesia
description: "Use for these drug classes specifically: cardiovascular agents and the mechanisms behind antihypertensives, anticoagulants and lipid-lowering therapy, anti-infectives with the mechanisms, spectrum and the resistance pressure that shapes prescribing, and analgesia across non-opioid and opioid agents including tolerance, dependence and the pain-management trade-offs. Technical orientation, not medical advice or prescribing guidance."
---

# Medicine and Pharmacology: Cardiovascular, Anti-infectives, and Analgesia

> **Part 3 of 6** of the *Fundamentals of Medicine and Pharmacology* reference (plugin `medicine-and-pharmacology-fundamentals`), covering §13–§15. Sibling skills: `med-reading-the-field-physiology-and-clinical-reasoning` (§0–§6), `med-pharmacokinetics-pharmacodynamics-and-interactions` (§7–§12), `med-drug-classes-neuro-endocrine-immunology-and-oncology` (§16–§19), `med-evidence-trials-safety-screening-and-ethics` (§20–§26), `med-reference` (§27–§32). Section numbers are shared across the set; a reference written as §N → `skill` points into that sibling skill.
>
> **Currency:** The physiology and pharmacology are stable. Two areas are moving fast. See §27 → `med-reference` for incretin therapeutics, and antimicrobial resistance.

> **⚠️ NOT MEDICAL ADVICE, and this matters more here than in any other file in this
> series.** ⚠️ **Nothing here is a diagnosis, a treatment recommendation, or dosing
> guidance. Individual clinical decisions require a licensed clinician who knows your
> history, and no general reference substitutes for that.**
>
> **⚠️ This is pitched where a preclinical survey or an informed-patient reference sits:
> the concepts that let you understand what medicine is doing and evaluate claims about
> it.** ⚠️ **It deliberately contains no dosing tables, no specific regimens, and no
> operational detail.**
>
> **Complements an organic-chemistry reference (drug molecules and metabolism), a
> statistics-adjacent reference (trial methodology), and a speaking-and-influence reference
> (§20 → `med-evidence-trials-safety-screening-and-ethics`'s evidence-quality reasoning is the same skill).**
>
> **⚠️ GOTCHA** boxes mark where clinical intuition — including clinicians' intuition — is
> reliably wrong.
>
> **The three ideas that organize this document:**
> 1. **⚠️ A TEST RESULT IS NOT A DIAGNOSIS** (§6 → `med-reading-the-field-physiology-and-clinical-reasoning`). **The probability that a positive test
>    means disease depends on how likely disease was beforehand. This single Bayesian fact
>    is the most useful thing in clinical medicine and the most consistently misunderstood
>    by patients and clinicians alike.**
> 2. **⚠️ EVERY DRUG IS A POISON AT SOME DOSE, AND EVERY EFFECT HAS A COST** (§9 → `med-pharmacokinetics-pharmacodynamics-and-interactions`, §12 → `med-pharmacokinetics-pharmacodynamics-and-interactions`).
>    **There are no side effects — only effects, some of which you wanted. The therapeutic
>    question is always a ratio, never an absolute.**
> 3. **⚠️ MOST OF WHAT DETERMINES HEALTH HAPPENS OUTSIDE CLINICAL MEDICINE** (§25 → `med-evidence-trials-safety-screening-and-ethics`).
>    **Sanitation, nutrition, income, housing and vaccination did more for life expectancy
>    than the entire therapeutic pharmacopoeia, and clinical medicine's share of health
>    outcomes is smaller than its share of spending.**

---

## §13. Cardiovascular

**⚠️ Antihypertensives** by mechanism: ⚠️ **ACE inhibitors and ARBs (renin-angiotensin
system), calcium channel blockers, thiazide diuretics, beta blockers, and mineralocorticoid
receptor antagonists.**
**⚠️ Heart failure therapy** has shifted from symptom relief to ⚠️ **disease-modifying
combinations shown to reduce mortality — and note that the drugs that make patients feel
better and the drugs that keep them alive are not always the same, which is a general
lesson.**
**⚠️ Antithrombotics**: ⚠️ **antiplatelets versus anticoagulants act on different parts of
haemostasis; ⚠️ direct oral anticoagulants largely displaced warfarin because they need no
routine monitoring — a pharmacokinetic advantage translating into a practical one.**
**⚠️ Lipid modification**: ⚠️ **statins, ezetimibe, PCSK9 inhibitors — and cardiovascular
prevention is the clearest illustration of §20 → `med-evidence-trials-safety-screening-and-ethics`'s absolute-versus-relative risk problem,
because the same relative risk reduction means very different things at different baseline
risk.**
**⚠️ Antiarrhythmics** — ⚠️ **and the CAST trial is the canonical cautionary tale, where
suppressing arrhythmias on the ECG increased mortality: a surrogate endpoint moving the
right way while patients died** (§21 → `med-evidence-trials-safety-screening-and-ethics`).

---

## §14. ⚠️ Anti-infectives

```
⚠️ ⚠️ THE UNIQUE FEATURE OF THIS CLASS: ⚠️ you are treating an
   organism, not a receptor — ⚠️ so it EVOLVES, and every use
   selects for resistance. ⚠️ Antimicrobials are the only drug
   class whose effectiveness is a depletable shared resource
   (§27.2)
⚠️ ANTIBACTERIAL MECHANISMS  ⚠️ cell wall synthesis (beta-lactams,
   glycopeptides) · protein synthesis (macrolides,
   aminoglycosides, tetracyclines) · nucleic acid
   (fluoroquinolones) · metabolic pathways (sulfonamides)
   ⚠️ SELECTIVE TOXICITY works because these targets differ from
   human ones — ⚠️ which is why antibacterials are relatively
   safe and antivirals and antifungals are harder
⚠️ ⚠️ RESISTANCE MECHANISMS  ⚠️ enzymatic inactivation
   (beta-lactamases), target modification, efflux pumps,
   reduced permeability — ⚠️ and HORIZONTAL GENE TRANSFER, which
   means resistance spreads between species and not only by
   descent
⚠️ ⚠️ STEWARDSHIP PRINCIPLES  ⚠️ right drug, right dose, right
   duration, narrowest adequate spectrum · ⚠️ culture before
   treating where possible · ⚠️ de-escalate on results ·
   ⚠️ AND SHORTER COURSES ARE INCREASINGLY SUPPORTED BY
   EVIDENCE — ⚠️ the "always finish the course" advice is being
   revised for many indications, though this is a decision for
   the prescriber and not the patient
⚠️ ⚠️ ANTIBIOTICS DO NOT TREAT VIRAL INFECTIONS, and prescribing
   them for viral illness is a major driver of resistance
   while providing no benefit
⚠️ ANTIVIRALS  ⚠️ harder because viruses use host machinery;
   ⚠️ HIV combination therapy is the model — multiple targets
   simultaneously to make resistance improbable
⚠️ ANTIFUNGALS  ⚠️ hardest of all, because fungi are eukaryotes
   and share much of our biochemistry; ⚠️ resistance is rising
   and the pipeline is thin (§27.2)
⚠️ VACCINES  ⚠️ prevention rather than treatment, and among the
   highest-value interventions in all of medicine (§25)
```

---

## §15. ⚠️ Analgesia

**⚠️ Pain is a perception, not a signal** — ⚠️ **nociception is the sensory input; pain is
what the brain constructs from it, modulated by context, expectation, mood and prior
experience.** ⚠️ **This is why psychological interventions have real analgesic effects and
why pain without tissue damage is not imaginary.**
**⚠️ The mechanisms available**: ⚠️ **NSAIDs and paracetamol act peripherally and centrally
on inflammatory and other pathways; ⚠️ opioids act on opioid receptors; ⚠️ adjuvants
(certain antidepressants and anticonvulsants) treat NEUROPATHIC pain, which responds poorly
to conventional analgesics; ⚠️ local anaesthetics block conduction.**
**⚠️ NSAIDs' limits** are the ones people underestimate: ⚠️ **gastrointestinal, renal and
cardiovascular risk, all dose- and duration-related.**
> **⚠️ GOTCHA — the opioid story is a case study in how evidence and incentive failure
> combine.** ⚠️ **Claims of low addiction risk in chronic non-cancer pain were promoted on
> very weak evidence, prescribing expanded enormously, and the resulting harm was severe.**
> **⚠️ The subsequent correction has its own harms — patients with legitimate severe pain,
> including cancer and palliative patients, facing under-treatment.** ⚠️ **Both failures are
> real and the field is still calibrating.**

**⚠️ Tolerance, dependence and addiction are three different things** — ⚠️ **physical
dependence is an expected pharmacological adaptation and is not addiction, which is a
behavioural disorder.** ⚠️ **Conflating them harms patients in both directions.**
**⚠️ Multimodal analgesia** — ⚠️ **combining mechanisms to reduce reliance on any one — is
current best practice.**