Hoja de repaso: Pharmacology Essentials for Healthcare

📋 Course Outline

1. Autonomic receptor pharmacology
2. Psychopharmacology and antipsychotics
3. Antimicrobials and resistance
4. Diuretics and antihypertensives
5. Drug absorption and distribution
6. Therapeutic drug monitoring and lab tests
7. Toxicology and antidotes
8. Endocrine and diabetes therapy
9. Cardiovascular and antiplatelet drugs
10. Drug mechanisms and clinical uses

📖 1. Autonomic receptor pharmacology

🔑 Key Concepts & Definitions

• Clonidine : Clonidine is a centrally acting alpha2-adrenergic agonist used for hypertension and related off-label indications.
• Parasympatholytic drugs : Parasympatholytic drugs antagonize parasympathetic (muscarinic) signaling to reduce secretions and inhibit smooth-muscle activity.
• Beta-adrenergic receptors : Beta-adrenergic receptors are adrenergic receptor subtypes whose stimulation produces smooth-muscle and cardiovascular effects.

📝 Essential Points

• Clonidine is centrally acting, increases vagal tone, and is used in opioid withdrawal treatment.
• Clonidine is contraindicated in angina according to the false-statement item.
• Stimulation of beta-adrenergic receptors relaxes the uterus in the tested options.
• Parasympatholytic drugs are not expected to relax the bladder sphincter in the tested options.

💡 Memory Hook

Clonidine: Alpha2 “center” → calmer sympathetic output; Parasympatholytics → dry/wide pupils, but bladder sphincter doesn’t relax.

📖 2. Psychopharmacology and antipsychotics

🔑 Key Concepts & Definitions

• Antidopaminergic neuroleptics : Antidopaminergic neuroleptics are antipsychotic drugs that reduce dopamine signaling and thereby trigger typical extrapyramidal adverse effects.
• Pseudo-parkinsonian syndrome : Pseudo-parkinsonian syndrome is an extrapyramidal reaction that can appear after treatment with certain dopamine-blocking antipsychotics.
• Benzodiazepines : Benzodiazepines are anxiolytic drugs whose effects depend on binding to GABA-mediated neurotransmission.
• Clozapine : Clozapine is an atypical antipsychotic noted for a lower risk of extrapyramidal symptoms than many typical agents.

📝 Essential Points

• Chlorpromazine and phenothiazine neuroleptics can cause extrapyramidal syndrome due to their antidopaminergic action.
• Pseudo-parkinsonian syndrome can be observed after haloperidol treatment.
• Benzodiazepines produce amnesia and muscle relaxation but are not antidepressants.
• Aripiprazole is least likely among listed atypical antipsychotics to cause extrapyramidal symptoms.
• Clozapine is not associated with pseudoparkinsonism as a potential adverse effect in the provided options.

💡 Memory Hook

Haloperidol causes pseudo-parkinsonism; clozapine/ aripiprazole are the “low EPS” antipsychotics.

📖 3. Antimicrobials and resistance

🔑 Key Concepts & Definitions

• Metronidazole : An antimicrobial often used for anaerobic infections that causes a potentially dangerous reaction when taken with alcohol.
• Bismuth metronidazole tetracycline : A proton-pump inhibitor–based regimen that pairs bismuth with metronidazole and tetracycline to eradicate Helicobacter pylori.
• Liposomal amphotericin B : A formulation of amphotericin B whose clinical use focuses on reducing nephrotoxicity while maintaining antifungal activity.
• Ertapenem : A carbapenem antibiotic that lacks coverage against Pseudomonas aeruginosa.

📝 Essential Points

• Metronidazole should not be used with alcohol because it can produce a disulfiram-like reaction.
• A common H. pylori regimen is a proton pump inhibitor plus bismuth, metronidazole, and tetracycline.
• Liposomal amphotericin B decreases nephrotoxicity compared with conventional amphotericin B.
• Ertapenem does not have coverage against P. aeruginosa.
• In chronic pro-drug administration, increased CYP expression leading to conversion to the active drug results in increased efficacy.
• For possible MRSA respiratory tract infections, daptomycin is not recommended.

💡 Memory Hook

Metronidazole + alcohol = “disulfiram-like” reaction (think D I S: disulfiram mimic).

📖 4. Diuretics and antihypertensives

🔑 Key Concepts & Definitions

• Mannitol : Mannitol is an osmotic diuretic used to reduce cerebral edema in acute brain injury settings.
• Loop diuretics : Loop diuretics are diuretics that act in the loop of Henle to increase salt and water excretion.
• Thiazide diuretics : Thiazide diuretics are diuretics that act in the distal tubule to inhibit sodium reabsorption.
• ACE inhibitors : ACE inhibitors are antihypertensives that reduce angiotensin II–mediated vasoconstriction and support improved cardiovascular hemodynamics.
• Central nervous system diuretics : Centrally acting agents are antihypertensives that act via the CNS rather than direct renal tubular effects.

📝 Essential Points

• Mannitol is most useful for acute treatment of a comatose patient with brain injury and cerebral edema.
• Acetazolamide’s mechanism is carbonic anhydrase inhibition.
• Thiazide diuretics inhibit the NaCl cotransporter in the distal tubule.
• Furosemide’s mechanism is inhibition of the NaK2Cl transporter.
• Ototoxicity is a unique side effect associated with loop diuretics.
• ACE inhibitors improve cardiovascular hemodynamics by antagonizing angiotensin II’s vasoconstrictive effects at its receptors.

💡 Memory Hook

Think: Loop = NaK2Cl; Thiazide = distal NaCl; Acetazolamide = carbonic anhydrase.

📖 5. Drug absorption and distribution

🔑 Key Concepts & Definitions

• Partition constant : A physical property describing how a drug distributes between lipid and water phases, affecting how easily it moves between body compartments.
• Volume of distribution : A pharmacokinetic parameter linking the amount of drug in the body to the measured plasma concentration, reflecting extent of tissue distribution.
• Urinary ion trapping : A distribution principle where increasing urine pH alters a weak acid or base ionization state, reducing back-diffusion and increasing renal drug elimination.

📝 Essential Points

• The degree of movement of a drug between body compartments is determined by its partition constant, degree of ionization, and size.
• In salicylate poisoning, giving sodium bicarbonate increases elimination by urinary ion trapping of salicylate.
• For a weak acid drug with pKa 5.2 (naproxen), plasma pH makes it predominantly ionized, so the fraction water soluble is >99%.
• Insulin absorption from an injection site is explained best by endocytosis.
• For an acidic drug with pKa about 9 (HCTZ), the main site of absorption is most likely the stomach.
• If a dose-proportional feature is tested by food-drug interaction, milk is said to enhance ciprofloxacin absorption, which is the incorrect statement.

💡 Memory Hook

Think “pH traps”: bicarbonate raises urine pH so ionized salicylate can’t easily slip back into blood.

📖 6. Therapeutic drug monitoring and lab tests

🔑 Key Concepts & Definitions

• Therapeutic drug monitoring : Therapeutic drug monitoring is a clinical practice that measures drug levels to guide safe dosing and effectiveness.
• Therapeutic range : Therapeutic range is the blood concentration interval linked to desired effects while minimizing toxicity.
• Digoxin therapeutic range : Digoxin therapeutic range is the adult serum concentration interval used to reduce the risk of toxicity.
• Hemoglobin A1c : Hemoglobin A1c is a lab test used to assess long-term glycemic control in monitoring follow-up.

📝 Essential Points

• Therapeutic drug monitoring is recommended for antiepileptics, aminoglycosides, and digitalis, except anti-vitamin K therapy.
• In adults, the therapeutic range for digoxin is 0.8 to 2 ng/mL.
• A normal platelet count is between 150,000 and 450,000 cells/μL, and a low platelet count is termed thrombocytopenia.
• The normal triglyceride level is below 150 mg/dL.
• For diabetic monitoring and follow-up, Hemoglobin A1c is the indicated test. (
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📖 7. Toxicology and antidotes

🔑 Key Concepts & Definitions

• Toxicology : Toxicology is the study of adverse effects that chemical substances cause in the body.
• Antidote : An antidote is a medicine that counteracts a specific poisoning mechanism to reduce toxicity or prevent death.
• Hemoperfusion with charcoal : Hemoperfusion with activated charcoal is a blood-treatment technique that filters anticoagulated blood through charcoal or resin particles.
• N-acetylcysteine : N-acetylcysteine is an antidote used to prevent liver failure after overdoses of analgesics that form a toxic quinone imine metabolite.
• Naloxone : Naloxone is an antidote used for opioid overdose characterized by respiratory depression and bilateral miosis.

📝 Essential Points

• Clinical toxicity secondary to accidental exposure is termed poisoning, intoxication, or overdose depending on context, with toxicology describing the field studying such events.
• An antidote for an overdose that commonly causes death from respiratory arrest due to bilateral miosis is naloxone.
• The antidote used to prevent liver failure in analgesic overdose that produces a toxic quinone amine metabolite is N-acetylcysteine.
• The first drug of choice for a toxidrome with constricted pupils, twitching, and labored breathing is atropine.
• An anticoagulated-blood filtration technique using a column with activated charcoal or resin particles is called hemoperfusion with charcoal/resin.

💡 Memory Hook

Match the toxidromes: opioid miosis→Naloxone; acetaminophen-like liver failure→N-acetylcysteine; benzodiazepine sedation→Flumazenil; cholinergic signs→Atropine.

📖 8. Endocrine and diabetes therapy

🔑 Key Concepts & Definitions

• HemoglobinA1c : HemoglobinA1c is a blood test that reflects average glycemic control over the preceding weeks rather than an individual glucose reading.
• Metformin : Metformin is a first-line drug for type 2 diabetes that is chosen early in treatment for many newly diagnosed patients.
• Canagliflozin : Canagliflozin is a diabetes drug whose side effects can include genital infections during clinical use.
• Insulin Degludec : Insulin degludec is an insulin analog designed for a prolonged duration of action.

📝 Essential Points

• In diabetic patients’ monitoring and follow-up, the indicated test is HemoglobinA1c, not peptide C or insulinemia.
• For a newly diagnosed overweight patient with type 2 diabetes and HbA1c 7.5%, the best initial add-on therapy is metformin.
• In clinical trials with canagliflozin, an adverse event reported is genital infections.
• For insulin analog duration, insulin degludec has the longest duration of action among the listed options.
• The recommended calcium dose in geriatrics is 1200 mg.

💡 Memory Hook

A1c tracks averages; Metformin starts first; Canagliflozin → genital infections; Degludec lasts longest; Geriatrics calcium = 1200 mg.

📖 9. Cardiovascular and antiplatelet drugs

🔑 Key Concepts & Definitions

• Evolocumab : Evolocumab is a monoclonal antibody used to reduce LDL cholesterol and act by blocking PCSK9.
• Apixaban : Apixaban is an oral anticoagulant that directly inhibits factor Xa to reduce clot formation.
• Digoxin : Digoxin is a cardiac glycoside used to treat atrial fibrillation by increasing vagal tone.
• Low molecular weight heparins : Low molecular weight heparins are anticoagulants that include enoxaparin and tinzaparin but exclude fondaparinux.

📝 Essential Points

• Diltiazem slows conduction through the AV node and has primary action directly on L-type calcium channels.
• In microalbuminuria, ACE inhibitors or ARBs are recommended to treat the patient.
• For chronic heart failure, optimal pharmacotherapy is furosemide, lisinopril, and carvedilol.
• Apixaban’s mechanism is direct inhibition of factor Xa.
• Digoxin treats arrhythmias by increasing vagal tone.
• Among antiplatelet agents, dabigatran does not have antiplatelet properties.],

📖 10. Drug mechanisms and clinical uses

🔑 Key Concepts & Definitions

• Furosemide–amiodarone interaction : Drug interaction involving furosemide and amiodarone that can produce clinically significant effects during co-administration.
• Octreotide for variceal bleeding : Somatostatin analog that treats bleeding esophageal varices by producing vasoconstriction.
• Amiodarone thyroid effects : Amiodarone can alter thyroid function and increases the risk of hypothyroidism within months of therapy.

📝 Essential Points

• In the case described, the significant drug interaction is between furosemide and amiodarone.
• Octreotide is used to treat bleeding of esophageal varices by causing vasoconstriction.
• Optimal chronic heart failure pharmacotherapy (from the options) is furosemide plus lisinopril plus carvedilol.
• With a markedly suppressed TSH of 0.041 mIU/ml, the most appropriate levothyroxine modification is to decrease the dose to 100 mcg oral daily.
• Amiodarone therapy increases the risk of developing hypothyroidism within 6 months of therapy.

💡 Memory Hook

Amiodarone → thyroid disturbance: think “watch TSH” (hypothyroidism risk within ~6 months).

📊 Synthesis Tables

Diuretic mechanisms (site/target)

Antipsychotic EPS risk (as stated)

⚠️ Common Pitfalls & Confusions

1. Mixing up clonidine’s effect (centrally acting; increases vagal tone for opioid withdrawal) with contraindications like angina, which are used as false statements in questions.
2. Confusing which antipsychotic is linked to pseudo-parkinsonism: haloperidol (yes) vs clozapine/aripiprazole being lower-EPS in the provided options.
3. Thinking benzodiazepines are antidepressants; the source states they produce amnesia and muscle relaxation but are not antidepressants.
4. Blaming the wrong drug for H. pylori “bismuth + metronidazole + tetracycline” regimens (they’re paired with a proton pump inhibitor).
5. Assuming ertapenem covers Pseudomonas aeruginosa; the source states it does not have coverage against P. aeruginosa.
6. For salicylate poisoning, giving bicarbonate with the wrong rationale: it works by urinary ion trapping (raising urine pH to increase elimination), not by “decreasing absorption.”
7. Mixing up toxicology antidotes: naloxone for opioid overdose with bilateral miosis/respiratory depression; N-acetylcysteine for acetaminophen-like toxic metabolite preventing liver failure; flumazenil is for benzodiazepines.

✅ Exam Checklist

1. Autonomic section: identify clonidine as centrally acting, knows it increases vagal tone, and recall the false statement about angina contraindication.
2. Autonomic section: distinguish beta-adrenergic stimulation effect (relaxation of the uterus) from parasympatholytic effects (no relaxation of the bladder sphincter in the tested options).
3. Antipsychotics: link antidopaminergic neuroleptics (chlorpromazine/phenothiazines) to extrapyramidal syndrome and recognize haloperidol → pseudo-parkinsonian syndrome.
4. Antipsychotics: compare EPS risk among atypicals—clozapine not associated with pseudoparkinsonism (in options) and aripiprazole least likely among listed for EPS.
5. Antimicrobials/resistance: apply metronidazole + alcohol as disulfiram-like reaction and recall the standard H. pylori regimen (PPI + bismuth + metronidazole + tetracycline).
6. Antimicrobials/resistance: recall liposomal amphotericin B reduces nephrotoxicity vs conventional amphotericin B, and ertapenem does not cover P. aeruginosa.
7. Diuretics/antihypertensives: match mechanisms—thiazides inhibit distal NaCl cotransporter, loop diuretics inhibit NaK2Cl, acetazolamide inhibits carbonic anhydrase, and mannitol is for acute cerebral edema in comatose brain injury.
8. Drug absorption/distribution: use partition constant + ionization + size to predict compartment movement; know sodium bicarbonate increases elimination in salicylate poisoning via urinary ion trapping.
9. Therapeutic drug monitoring/labs: state TDM applies to antiepileptics, aminoglycosides, and digitalis; recognize digoxin adult therapeutic range 0.8–2 ng/mL and HbA1c for long-term glycemic monitoring.
10. Toxicology/antidotes: map toxidromes—opioid miosis/respiratory depression → naloxone; acetaminophen-like toxic quinone metabolite liver failure prevention → N-acetylcysteine; (as stated) first toxidrome option with constricted pupils/labored breathing → atropine; benzodiazepine sedation → flumazenil.
11. Endocrine/diabetes: select HbA1c for monitoring follow-up; recall metformin as best initial add-on for newly diagnosed overweight type 2 with HbA1c 7.5%; canagliflozin adverse event = genital infections; insulin degludec has longest duration; geriatrics calcium dose = 1200 mg.
12. Cardiovascular/antiplatelet & mechanisms: recall apixaban direct factor Xa inhibition, digoxin increases vagal tone, and evolocumab blocks PCSK9 to reduce LDL.
13. Drug mechanisms/clinical uses: identify furosemide + amiodarone as significant interaction; octreotide for esophageal variceal bleeding via vasoconstriction; amiodarone hypothyroidism risk within ~6 months and TSH 0.041 mIU/ml → decrease levothyroxine dose to 100 mcg daily (per options).