sarcidosis

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sarcoidosis

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Sarcoidosis

Definition and Epidemiology

Sarcoidosis is a chronic multisystem granulomatous disease of unknown etiology, characterized by the formation of non-caseating (non-necrotizing) granulomas in affected tissues. It occurs worldwide, in patients of every age, ethnicity, and socioeconomic class, though patterns of prevalence vary considerably.

Prevalence: Highest in Scandinavia (Sweden: 64/100,000). In the United States: 10.9/100,000 in White persons vs. 35.5/100,000 in African Americans.
Sex: Women are slightly more affected, particularly African American women aged 30-39. Late-onset disease (ages 65-69) is 5x more common in women.
Lifetime risk: 0.85% (White U.S. residents) vs. 2.4% (Black U.S. residents).
Onset: Most commonly between ages 20-40, with a second peak at ages 65-69.
Andrews' Diseases of the Skin, p. 1321

Pathophysiology

The disease is driven by a Th1/Th17 immune response in which activated macrophages and CD4+ helper T cells form granulomas. IL-2 and IFN-γ secreting CD4+ Th cells play a key role, along with TNF and other Th1/Th17 cytokines.

Circulating cytokines, chemokines, and other mediators not only cause direct granulomatous organ damage but also produce systemic symptoms (fatigue, fever, weight loss, depression) through non-tissue-damaging mechanisms - called parasarcoidosis syndromes.

Key genetic associations:

HLA-DRB1 variants increase risk
HLA-DQB1*0201 and HLA-DRB1*0301 associate with acute disease and good prognosis
HLA-B8/DR3 associated with Löfgren syndrome
TNF promoter polymorphisms linked to erythema nodosum
ANXA11, BTNL2, CCR5 polymorphisms also identified

A notable metabolic effect: active sarcoidosis upregulates 1-alpha-hydroxylase, converting inactive 25-OH vitamin D to active 1,25-OH vitamin D, causing hypercalcemia.

Fishman's Pulmonary Diseases and Disorders, pp. 470-475

Organ Involvement

Sarcoidosis earns its reputation as a "great imitator" - it can affect virtually any organ.

Organ System	Prevalence	Key Manifestations
Pulmonary	>90%	Restrictive/obstructive disease, reduced DLCO, bilateral hilar adenopathy, pulmonary fibrosis, pulmonary hypertension
Constitutional	>50%	Fever, night sweats, fatigue, weight loss
Skin	20-30%	Lupus pernio, papules/plaques/nodules, erythema nodosum, scar/tattoo granulomas
Eyes	20-30%	Anterior/posterior uveitis, optic neuritis, chorioretinitis
Hematologic	20-30%	Lymphadenopathy, splenomegaly, anemia, lymphopenia
Cardiac	5-20%	Arrhythmias, heart block, dilated cardiomyopathy, sudden death
Liver/abdominal	10-20%	Hepatomegaly, granulomatous hepatitis, portal hypertension
Joints/MSK	10-20%	Arthralgia, polyarthritis, Achilles tendinitis, dactylitis
Neurologic	5-10%	Bell's palsy (most common), basilar meningitis, optic neuropathy, small fiber neuropathy
Renal	<10%	Nephrocalcinosis, renal calculi, interstitial nephritis

Fishman's Pulmonary Diseases and Disorders, Table 53-2

Key Specific Syndromes

Löfgren Syndrome: Acute triad of erythema nodosum + bilateral hilar adenopathy + periarthritis/arthritis, typically with fever. Generally carries a good prognosis.

Lupus Pernio: Indurated plaques/nodules on the nose and central face - a marker of chronic sarcoidosis strongly associated with upper airway granulomatous infiltration, pulmonary fibrosis, and persistent pulmonary involvement.

Cardiac Sarcoidosis: Clinically apparent in <10% of U.S. cases, but autopsy studies show myocardial involvement in >20% (U.S.) and >50% (Japan). Ventricular arrhythmias and high-degree heart block can cause sudden death.

Neurosarcoidosis: Cranial neuropathies dominate; VII nerve (Bell's) palsy is most common. Hypothalamic involvement can cause diabetes insipidus, hypogonadism, or hyperprolactinemia.

Chest Radiographic Staging (Scadding)

Stage	Finding	Prognosis
0	Normal	-
I	Bilateral hilar adenopathy only	>80% resolve at 2-5 years
II	Hilar adenopathy + parenchymal infiltrates	Intermediate
III	Parenchymal infiltrates only (no adenopathy)	<30% resolve
IV	Pulmonary fibrosis	Does not resolve

Diagnosis

The diagnosis is never fully secure and requires:

Compatible clinical and radiologic presentation
Histologic demonstration of non-necrotizing granulomas (ideally in two or more organs)
Exclusion of other causes (especially tuberculosis, fungal infections, other granulomatous diseases)

Useful workup:

Chest radiograph and HRCT
Pulmonary function tests (FVC, DLCO - DLCO is the most sensitive early marker)
Serum ACE (angiotensin-converting enzyme) - elevated in ~60%, neither sensitive nor specific
24-hour urinary calcium (hypercalciuria)
LFTs, renal function, serum calcium
Ophthalmologic examination (slit-lamp)
ECG (screening for cardiac involvement)
Serum LDH, lysozyme
BAL: CD4:CD8 ratio >3.5 is suggestive
FDG-PET/CT: useful for detecting active inflammation in cardiac and neurologic sarcoidosis and identifying the best biopsy site
Cardiac MRI with gadolinium: reveals myocardial inflammation and scarring in a non-coronary distribution

Biopsy sites (least invasive first): skin lesions, peripheral lymph nodes, transbronchial lung biopsy (high yield ~70-90%), EBUS-guided mediastinal biopsy.

The historical Kveim test (intradermal inoculation of sarcoid splenic tissue) is now essentially obsolete.

Murray & Nadel's Textbook of Respiratory Medicine, pp. 3565-3575

Treatment

There are no FDA-approved systemic therapies for sarcoidosis. Treatment is indicated for threatened organ function, not just for the presence of disease.

Indications for Treatment

Severe ocular, cardiac, or neurologic disease
Progressive, persistent, or symptomatic pulmonary disease
Disfiguring cutaneous disease (especially lupus pernio)
Persistent hypercalcemia
Renal or hepatic dysfunction
Symptomatic myopathy, painful lymphadenopathy
Severe fatigue and weight loss

Treatment Ladder

1. Corticosteroids (first-line)

Prednisone 20-40 mg/day, tapered slowly to maintenance 5-15 mg/day
Duration: minimum 6-24 months (premature taper leads to relapse)
Inhaled corticosteroids have limited effectiveness alone
Löfgren syndrome: NSAIDs first; corticosteroids if arthritis is disabling

2. Steroid-sparing agents (second-line)

Hydroxychloroquine (200-400 mg/day): particularly for skin and hypercalcemia
Methotrexate (7.5-15 mg/week): most widely used second-line agent
Azathioprine: alternative immunosuppressant

3. Biologics (refractory disease)

Infliximab (anti-TNF): evidence-based for pulmonary and cutaneous sarcoidosis; a recent 2025 systematic review and meta-analysis (PMID: 40393718) confirmed efficacy of biologic and targeted synthetic therapies in sarcoidosis
Adalimumab: alternative anti-TNF
Caution: anti-TNF agents are contraindicated in active infections (especially TB - screening required)

Cutaneous disease specifically:

Intralesional corticosteroid injections (first-line for localized lesions, repeated every 2-4 weeks)
Topical steroids often inadequate (poor penetration of thick granulomas)
Hydroxychloroquine or methotrexate for refractory/widespread disease
Fishman's Pulmonary Diseases and Disorders, pp. 597-619
Textbook of Family Medicine 9e, p. 489

Prognosis

Stage I disease: excellent prognosis; most resolve spontaneously
Stage II/III: ~50-70% improve with treatment
Stage IV (fibrotic): irreversible
Chronic progressive disease occurs in >20% overall
Monitoring for at least 3 years after apparent remission is recommended; longer for serious pulmonary or extrapulmonary disease
Special concern: aspergilloma can develop in cavitary/fibrotic upper lobe lesions and is a serious complication

Recent evidence: A 2025 systematic review and meta-analysis in Thorax (PMID: 40393718) confirmed the efficacy of biologics (particularly anti-TNF agents) in sarcoidosis - relevant for refractory cases where standard immunosuppression has failed.

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pharmacology 2nd year mbbs CNS chapter answers and questions for mpmsu exams

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MPMSU 2nd year MBBS pharmacology CNS chapter previous year questions

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2nd Year MBBS Pharmacology - CNS Chapter

MPMSU Exam Questions & Answers

Topics based on MPMSU/MCI 2nd Prof pattern: General Anesthesia, Sedative-Hypnotics, Antiepileptics, Antiparkinsonians, Antipsychotics, Antidepressants, Opioid Analgesics, Alcohol

SECTION A - LONG ANSWER QUESTIONS (10 Marks)

Q1. Classify antiepileptic drugs. Describe the pharmacological actions, mechanism of action, uses, and adverse effects of Phenytoin.

CLASSIFICATION OF ANTIEPILEPTIC DRUGS:

Based on mechanism:

Drug	Mechanism	Seizure Type
Phenytoin	Na⁺ channel blocker	Focal, generalized tonic-clonic
Carbamazepine	Na⁺ channel blocker	Focal, generalized tonic-clonic
Valproic acid	Multiple (Na⁺ block + GABA ↑ + T-Ca²⁺ block)	All types including absence
Phenobarbital	GABA potentiation	Focal, generalized
Ethosuximide	T-type Ca²⁺ channel blocker	Absence seizures only
Benzodiazepines (Diazepam, Lorazepam)	GABA-A potentiation	Status epilepticus, acute
Levetiracetam	SV2A modulation	Focal and generalized
Lamotrigine	Na⁺ channel blocker	Focal and generalized

PHENYTOIN (Diphenylhydantoin)

Mechanism of Action:

Blocks voltage-gated sodium channels in a use-dependent (frequency-dependent) manner
Preferentially binds to the inactivated state of Na⁺ channels, prolonging the refractory period
Prevents repetitive high-frequency neuronal firing without affecting normal low-frequency firing
Also has minor effects on calcium channels and GABA

Pharmacological Actions:

Anticonvulsant: suppresses focal seizure activity and prevents spread
Antiarrhythmic: Class IB (stabilizes cardiac membranes)
No sedation at therapeutic doses (unlike phenobarbital)

Pharmacokinetics:

Oral bioavailability: ~90%
Protein binding: ~90% (to albumin)
Zero-order (non-linear) kinetics at therapeutic doses - small dose increments cause disproportionate rise in plasma levels
Hepatic enzyme inducer (CYP2C9, CYP2C19): reduces efficacy of warfarin, OCP, corticosteroids
Therapeutic plasma level: 10-20 mcg/mL
Half-life: variable (dose-dependent), approximately 20-60 hours

Uses:

Generalized tonic-clonic seizures (first-line)
Focal (partial) seizures
Status epilepticus (IV phenytoin/fosphenytoin)
Trigeminal neuralgia
Cardiac arrhythmias (digitalis-induced)

Adverse Effects:

Dose-related (common): Nystagmus (earliest sign), ataxia, diplopia, mental confusion, sedation
Chronic/long-term:
- Gingival hyperplasia (common in children, due to collagen accumulation)
- Hirsutism, acne
- Coarsening of facial features
- Folate deficiency → megaloblastic anemia
- Vitamin D deficiency → osteomalacia
- Peripheral neuropathy
Idiosyncratic: Skin rashes (morbilliform), Stevens-Johnson syndrome
Teratogenic: Fetal hydantoin syndrome (cleft palate, digital/nail hypoplasia, microcephaly)
IV rapid infusion: Hypotension, cardiac arrhythmias, "purple glove syndrome"

Adams and Victor's Principles of Neurology, 12th Ed; Katzung's Basic & Clinical Pharmacology, 16th Ed

Q2. Classify antipsychotic drugs. Describe the pharmacological actions, mechanism of action, uses, and adverse effects of Chlorpromazine.

CLASSIFICATION OF ANTIPSYCHOTIC DRUGS:

First Generation (Typical/Conventional) - D2 antagonists:

Phenothiazines:
- Aliphatic: Chlorpromazine, Triflupromazine
- Piperazine: Fluphenazine, Trifluoperazine
- Piperidine: Thioridazine
Butyrophenones: Haloperidol, Droperidol
Thioxanthenes: Flupenthixol

Second Generation (Atypical) - D2 + 5-HT2A antagonists:

Clozapine (gold standard for refractory schizophrenia)
Risperidone, Olanzapine, Quetiapine, Aripiprazole, Ziprasidone

CHLORPROMAZINE (CPZ)

Mechanism of Action:

Primary: Blocks postsynaptic D2 dopamine receptors (mesolimbic and mesocortical pathways)
Also blocks: α1-adrenoceptors, H1-histamine, muscarinic (M1), and 5-HT2 receptors
The antipsychotic effect is due to D2 blockade in the mesolimbic pathway (reduces positive symptoms)
D2 blockade in the nigrostriatal pathway causes extrapyramidal side effects
D2 blockade in the tuberoinfundibular pathway causes hyperprolactinemia

Pharmacological Actions:

CNS effects:

Antipsychotic: reduces hallucinations, delusions (positive symptoms)
Sedation (via H1 blockade)
Antiemetic: blocks D2 in chemoreceptor trigger zone (CTZ)
Hypothermia (poikilothermia)
Lowers seizure threshold

Peripheral effects:

Hypotension: α1 blockade (orthostatic hypotension)
Anticholinergic effects: dry mouth, urinary retention, constipation, blurred vision
Antihistaminic: sedation, weight gain

Uses:

Schizophrenia, mania, acute psychosis
Antiemetic (nausea/vomiting due to drugs, radiation, surgery)
Hiccups (intractable)
Pre-anesthetic medication (potentiates anesthetics)
Tetanus (as adjunct)
Chlorpromazine equivalents (reference drug for antipsychotic dosing)

Adverse Effects:

Extrapyramidal effects (EPS) - most important:

Acute dystonia (within hours-days): involuntary muscle spasms of face/neck - Rx: benztropine/diphenhydramine
Akathisia (weeks): restlessness, inability to sit still - Rx: propranolol, benzodiazepines
Drug-induced Parkinsonism (weeks-months): tremor, rigidity, bradykinesia - Rx: anticholinergics (trihexyphenidyl)
Tardive Dyskinesia (months-years): repetitive, involuntary orofacial movements - irreversible, no reliable treatment

Endocrine:

Hyperprolactinemia → galactorrhea, amenorrhea, gynecomastia, sexual dysfunction

Autonomic:

Orthostatic hypotension (dangerous in elderly), anticholinergic effects

Metabolic:

Weight gain, glucose intolerance (more with atypicals)

Rare but serious:

Neuroleptic Malignant Syndrome (NMS): hyperthermia, muscle rigidity, autonomic instability, elevated CPK - life-threatening emergency - Rx: stop drug, dantrolene, bromocriptine
Cholestatic jaundice, agranulocytosis (rare)
Lowers seizure threshold

Skin/eyes (chronic):

Photosensitivity, skin pigmentation
Corneal/lens deposits
Retinal pigmentation (thioridazine)

Goodman & Gilman's Pharmacological Basis of Therapeutics; Kaplan & Sadock's Comprehensive Textbook of Psychiatry

Q3. Classify opioid analgesics. Describe the pharmacological actions, mechanism, uses, and adverse effects of Morphine. Compare Morphine and Pethidine.

CLASSIFICATION OF OPIOID ANALGESICS:

Category	Drugs
Strong agonists (mu)	Morphine, Pethidine (Meperidine), Fentanyl, Methadone, Oxycodone
Moderate agonists	Codeine, Tramadol, Propoxyphene
Mixed agonist-antagonists	Pentazocine (κ agonist, μ antagonist), Buprenorphine (partial μ agonist)
Pure antagonists	Naloxone, Naltrexone

Opioid Receptor Types:

μ (Mu): Analgesia (supraspinal + spinal), euphoria, respiratory depression, constipation, physical dependence
κ (Kappa): Spinal analgesia, sedation, dysphoria, miosis
δ (Delta): Analgesia, mood modulation
All are GPCRs (Gi linked) → ↓ cAMP, ↑ K⁺ conductance (hyperpolarization), ↓ Ca²⁺ conductance

MORPHINE

Mechanism: Activates μ-opioid receptors (primarily) → inhibits adenylyl cyclase → hyperpolarizes neurons → decreases nociceptive transmission in dorsal horn and supraspinal centres

Pharmacological Actions:

CNS:

Analgesia: Effective for severe visceral and somatic pain; raises pain threshold and alters pain perception (reduces suffering)
Euphoria (in pain patients) or dysphoria (in pain-free subjects)
Sedation and drowsiness
Respiratory depression (medullary respiratory centre; most dangerous effect - due to μ receptor)
Antitussive: Suppresses cough reflex
Miosis (pin-point pupils): due to stimulation of Edinger-Westphal nucleus (parasympathetic) - does NOT develop tolerance - useful diagnostically in overdose
Nausea/vomiting: Stimulates CTZ

CVS:

Vasodilation (histamine release), orthostatic hypotension
Bradycardia

GIT:

Constipation: ↓ GI motility (peripheral μ receptors) - tolerance does NOT develop
Spasm of sphincter of Oddi (increases biliary pressure - caution in biliary colic)

Other:

Urinary retention (detrusor relaxation, sphincter contraction)
Pruritus (histamine release)

Pharmacokinetics:

Poor oral bioavailability (~25%) due to first-pass metabolism
Protein binding: ~35%
Metabolized in liver to morphine-6-glucuronide (active, potent) and morphine-3-glucuronide (inactive)
Duration: 4-6 hours
Excreted in urine (dose reduction needed in renal failure)

Uses:

Severe pain - post-op, MI (drug of choice for pain of MI), cancer pain
Acute pulmonary edema (via vasodilation, reduces preload + allays anxiety)
Preanesthetic medication
Antidiarrheal (as codeine/loperamide)
Cough suppression

Adverse Effects:

Respiratory depression (most dangerous), constipation, nausea/vomiting
Addiction/dependence and withdrawal syndrome
Histamine release → pruritus, bronchospasm
Urinary retention, biliary colic exacerbation

Tolerance: Develops to analgesia, euphoria, respiratory depression, nausea; does NOT develop to constipation and miosis

Opioid Overdose Triad: Coma + Pin-point pupils + Respiratory depression

Treatment: IV Naloxone (μ antagonist, 0.4-2 mg IV)

COMPARISON: MORPHINE vs PETHIDINE

Feature	Morphine	Pethidine (Meperidine)
Chemical class	Phenanthrene alkaloid	Phenylpiperidine (synthetic)
Potency	Standard (10 mg)	Less potent (75-100 mg = 10 mg morphine)
Duration	4-6 hours	2-3 hours (shorter)
Smooth muscle	More spasm (biliary, urinary)	Less smooth muscle spasm
Biliary/renal colic	Contraindicated (worsens spasm)	Preferred (less spasm)
CVS	Bradycardia	Tachycardia (atropine-like effect)
Antitussive	Yes	Less effective
Antidiarrheal	Used	Not used
Constipation	More	Less
Metabolite toxicity	Morphine-6-glucuronide (active)	Norpethidine (toxic - CNS excitation, seizures)
Seizure risk	Less	High (norpethidine)
Use in obstetrics	Prolonged effect on neonate	Preferred (shorter duration)
Use in MAO inhibitor patients	Safer	Contraindicated (serotonin syndrome risk)

Goodman & Gilman's Pharmacological Basis of Therapeutics, 14th Ed

SECTION B - SHORT ANSWER QUESTIONS (5 Marks)

Q4. Write a short note on Benzodiazepines / Diazepam.

BENZODIAZEPINES

Mechanism of Action:

Positive allosteric modulators of GABA-A receptors
Bind to the benzodiazepine binding site (between α and γ subunits of GABA-A receptor)
Increase the frequency of Cl⁻ channel opening (NOT the duration - that is barbiturates)
Result: enhanced Cl⁻ influx → hyperpolarization → reduced neuronal excitability
Require endogenous GABA to be present (cannot activate Cl⁻ channel alone)

Pharmacological Actions:

Anxiolytic (reduce anxiety without sedation at low doses)
Sedative-hypnotic
Anticonvulsant
Centrally-acting muscle relaxant
Anterograde amnesia

Uses:

Anxiety disorders (GAD, panic disorder) - lorazepam, alprazolam
Insomnia - temazepam, nitrazepam, triazolam
Status epilepticus - IV diazepam or lorazepam (drug of choice)
Alcohol withdrawal - chlordiazepoxide, diazepam
Preanesthetic medication - midazolam
Muscle relaxant - diazepam
Procedural sedation - midazolam

Adverse Effects:

Sedation, psychomotor impairment, anterograde amnesia
Respiratory depression (less than barbiturates)
Dependence and withdrawal (anxiety, insomnia, tremors, seizures)
Flumazenil (competitive antagonist) reverses effects

Advantage over barbiturates: Safer (wide therapeutic index, respiratory depression only at very high doses)

Q5. Write a short note on Levodopa (L-DOPA) in Parkinsonism.

PARKINSON'S DISEASE (PD): Degenerative loss of dopaminergic neurons in the substantia nigra (pars compacta) → depletion of dopamine in the striatum → imbalance between dopamine (reduced) and acetylcholine (relatively increased) → tremor, rigidity, bradykinesia, postural instability

LEVODOPA (L-DOPA):

Why not dopamine? Dopamine does not cross the blood-brain barrier (BBB). Levodopa (L-3,4-dihydroxyphenylalanine) is the amino acid precursor of dopamine and crosses the BBB via amino acid transporter.

Mechanism: L-DOPA → converted to dopamine by DOPA decarboxylase in the brain → replenishes striatal dopamine levels

Combined with Carbidopa:

Carbidopa is a peripheral DOPA decarboxylase inhibitor (does not cross BBB)
Prevents peripheral conversion of L-DOPA to dopamine
Benefits: Reduces dose of L-DOPA needed by ~75%, reduces peripheral side effects (nausea, vomiting, cardiac arrhythmias), increases CNS bioavailability
Standard preparation: Sinemet (carbidopa:levodopa = 1:4 or 1:10)

Pharmacological Effects:

Ameliorates all motor symptoms of PD: tremor, rigidity, bradykinesia (most effective drug for motor symptoms)
Akinesia and rigidity respond better than tremor

Adverse Effects:

Peripheral (due to dopamine formation outside CNS):

Nausea, vomiting (most common, reduced with carbidopa)
Cardiac arrhythmias
Orthostatic hypotension

Central:

Dyskinesias (involuntary choreoathetoid movements) - most troublesome long-term
On-off phenomenon (wearing-off and unpredictable fluctuations) - due to disease progression and altered pharmacokinetics
Psychiatric effects: vivid dreams, hallucinations, psychosis, impulse control disorders
Sleep attacks

Drug Interactions:

Pyridoxine (Vit B6) ↑ peripheral decarboxylation of L-DOPA → counteracts effect (not a problem with carbidopa combination)
MAO inhibitors (non-selective) → hypertensive crisis (contraindicated)
Antipsychotics (D2 blockers) → worsen parkinsonism
High-protein meals → compete with L-DOPA for intestinal transport

Katzung's Basic & Clinical Pharmacology, 16th Ed

Q6. Classify sedative-hypnotic drugs. Write the mechanism of action and uses of Barbiturates.

CLASSIFICATION OF SEDATIVE-HYPNOTICS:

Benzodiazepines: Diazepam, Lorazepam, Alprazolam, Midazolam, Nitrazepam
Barbiturates: Phenobarbital (long-acting), Thiopental (ultra-short), Amobarbital (intermediate)
Non-benzodiazepine hypnotics (Z-drugs): Zolpidem, Zopiclone, Zaleplon
Melatonin receptor agonists: Ramelteon
Miscellaneous: Chloral hydrate, Buspirone (for anxiety)

BARBITURATES:

Mechanism:

Enhance GABA-A receptor activity - INCREASE duration of Cl⁻ channel opening (vs. benzodiazepines which increase frequency)
At high doses, can directly activate Cl⁻ channel even without GABA (explaining their greater CNS depression and lethality)
Also block AMPA (glutamate) receptors

Thiopental Sodium (IV anesthesia):

Ultra-short acting (duration ~5-10 min) due to rapid redistribution from brain to muscle and fat
Used for induction of general anesthesia
Anticonvulsant (lowers cerebral metabolic rate - used in status epilepticus/raised ICP)
Stages of anesthesia: Analgesia → Excitement → Surgical anesthesia → Medullary depression

Phenobarbital:

Long-acting (t½ = 80-120 hours)
Antiepileptic: used in all types of seizures except absence
Hepatic enzyme inducer

Q7. Write a short note on Status Epilepticus and its treatment.

DEFINITION: Continuous seizure activity lasting >5 minutes OR ≥2 seizures without recovery of consciousness between them

Emergency management (stepwise):

Time	Drug	Dose/Route
0-5 min	Airway, oxygen, IV access, blood glucose	-
5-20 min	Lorazepam IV (first line) or Diazepam IV/rectal	Lorazepam 0.1 mg/kg IV
20-40 min	Fosphenytoin or Valproate IV if benzodiazepine fails	20 mg/kg IV
40+ min (refractory)	Phenobarbital IV or Midazolam/Propofol/Thiopental infusion (general anesthesia)	ICU setting

IV Lorazepam is drug of first choice for immediate management of status epilepticus.

Q8. Write a short note on Classification of Antidepressants with mechanism and uses.

CLASSIFICATION:

Class	Drugs	Mechanism
SSRIs (first line)	Fluoxetine, Sertraline, Paroxetine, Citalopram, Escitalopram	Block serotonin (5-HT) reuptake transporter (SERT)
SNRIs	Venlafaxine, Duloxetine	Block SERT + norepinephrine transporter (NET)
TCAs	Imipramine, Amitriptyline, Clomipramine	Block SERT + NET; also block H1, M1, α1 (many side effects)
MAO Inhibitors	Phenelzine, Tranylcypromine (irreversible); Moclobemide (reversible, MAO-A)	Inhibit MAO-A → ↑ 5-HT, NE; MAO-B inhibitors → ↑ dopamine (used in PD: selegiline)
Atypicals	Bupropion (NDRI), Mirtazapine (NaSSA), Trazodone	Various mechanisms

Key side effects to remember:

SSRIs: sexual dysfunction, serotonin syndrome (with MAOIs), GI upset, SIADH
TCAs: anticholinergic (dry mouth, retention, constipation), cardiotoxic (QT prolongation, arrhythmias in overdose), sedation, weight gain
MAOIs: Cheese reaction (hypertensive crisis with tyramine-rich food like aged cheese, red wine, beer)
Bupropion: lowers seizure threshold, no sexual dysfunction

Uses of antidepressants:

Major depressive disorder (primary use)
Anxiety disorders, OCD (SSRIs/SNRIs)
Neuropathic pain (duloxetine, amitriptyline)
Nocturnal enuresis (imipramine)
Panic disorder (SSRIs, TCAs)

SECTION C - SHORT NOTES / VIVA TOPICS (2-3 Marks)

Q9. Classify General Anesthetics. Write stages of anesthesia.

Classification:

Inhalational: Gas - Nitrous oxide (N₂O); Volatile liquids - Halothane, Isoflurane, Sevoflurane, Desflurane
Intravenous: Thiopental, Propofol, Ketamine, Etomidate, Midazolam

Stages of General Anesthesia (Guedel's - described for diethyl ether):

Stage	Name	Features
Stage I	Analgesia	Patient conscious, pain threshold raised, amnesia begins
Stage II	Excitement/Delirium	Irregular breathing, vomiting risk, dangerous stage - avoid stimulation
Stage III	Surgical Anesthesia	Regular breathing, muscle relaxation, 4 planes
Stage IV	Medullary Depression	Respiratory and CVS failure, death

Pre-anesthetic medication: Diazepam/midazolam (anxiolytic), morphine (analgesia), atropine (dry secretions, prevent bradycardia), metoclopramide (antiemetic)

Q10. Nitrous Oxide (Laughing Gas)

Colorless, odorless gas; weak anesthetic (MAC >100%) - cannot produce surgical anesthesia alone
Mechanism: NMDA receptor antagonism (blocks glutamate)
Used in combination with other agents (reduces their dose)
Excellent analgesia; used in dental procedures and obstetric analgesia
Diffuses rapidly into gas-filled cavities - contraindicated in: pneumothorax, bowel obstruction, middle ear surgery
Megaloblastic anemia with prolonged use (oxidizes Vit B12, inactivates methionine synthase)

Q11. Drug of Choice (DOC) - CNS Quick Reference

Condition	Drug of Choice
Status epilepticus (immediate)	IV Lorazepam (or Diazepam)
Tonic-clonic seizures	Valproate / Phenytoin
Absence seizures	Ethosuximide (or Valproate)
Febrile seizures	Diazepam (rectal/IV)
Parkinson's disease	Levodopa + Carbidopa
Schizophrenia	Haloperidol (typical) / Risperidone (atypical)
Refractory schizophrenia	Clozapine
Opioid overdose	Naloxone IV
Benzodiazepine overdose	Flumazenil IV
Neuroleptic Malignant Syndrome	Dantrolene + Bromocriptine
Manic episode	Lithium (or Valproate, Olanzapine)
Depression (first-line)	SSRI (Fluoxetine/Sertraline)
Nocturnal enuresis	Imipramine
Cheese reaction (MAOI)	Phentolamine (alpha blocker)
Methanol poisoning	Ethanol / Fomepizole + Folate

Q12. Alcohol (Methyl Alcohol Poisoning)

Methanol (wood alcohol) poisoning:

Metabolized by alcohol dehydrogenase → Formaldehyde → Formic acid (toxic metabolites)
Features: Visual disturbances → blindness (optic nerve/retina damage), metabolic acidosis (high anion gap), CNS depression
Treatment:
- Ethanol (competitive substrate for alcohol dehydrogenase - prevents methanol metabolism) OR
- Fomepizole (alcohol dehydrogenase inhibitor - preferred, fewer side effects)
- Sodium bicarbonate (correct acidosis)
- Folate (enhances formate metabolism)
- Hemodialysis (severe cases)

IMPORTANT EXAM MNEMONICS

Side effects of Chlorpromazine = ABCDE:

Agranulocytosis (rare), Anticholinergic effects
Blood pressure (hypotension), Block (heart - ECG changes)
Cholestatic jaundice, Corneal/lens deposits
Dyskinesias (tardive), Dopamine block → prolactin ↑
EPS (extrapyramidal side effects)

Opioid tolerance - "CAD" (where tolerance DOES develop): Cough suppression, Analgesia, respiratory Depression, euphoria (Tolerance does NOT develop to: Constipation, Miosis)

NMS vs Serotonin Syndrome:

Feature	NMS	Serotonin Syndrome
Cause	Antipsychotics (D2 block)	Serotonergic drugs (SSRI + MAOI)
Onset	Days-weeks	Hours
Muscle findings	Lead-pipe rigidity	Clonus, hyperreflexia
Temp	Hyperthermia	Hyperthermia
Treatment	Dantrolene + Bromocriptine	Cyproheptadine (5-HT antagonist)

Sources: Goodman & Gilman's Pharmacological Basis of Therapeutics | Katzung's Basic & Clinical Pharmacology, 16th Ed | Adams & Victor's Principles of Neurology, 12th Ed | Kaplan & Sadock's Comprehensive Textbook of Psychiatry | Stahl's Essential PsychopharmacologyHere is a complete MPMSU-pattern CNS Pharmacology Q&A, organized exactly as the exam expects.

What's Covered (All Major MPMSU CNS Topics):

Long Answer Questions (10 marks each):

Antiepileptic drugs - classification + Phenytoin (mechanism, uses, adverse effects)
Antipsychotics - classification + Chlorpromazine in full detail
Opioid analgesics - classification + Morphine + Morphine vs Pethidine comparison table

Short Answer Questions (5 marks each):

Benzodiazepines/Diazepam - GABA-A mechanism, frequency of Cl⁻ opening, uses
Levodopa + Carbidopa - why L-DOPA is used, on-off phenomenon, adverse effects
Sedative-hypnotics - classification + Barbiturate mechanism (duration of Cl⁻ channel opening)
Status Epilepticus - stepwise treatment ladder (lorazepam → fosphenytoin → thiopental)
Antidepressants - all classes (SSRI, TCA, MAOI, SNRI) with mechanisms

Short Notes / Viva (2-3 marks):

General anesthesia stages (Guedel's stages I-IV)
Nitrous oxide
Drug of Choice table (must-memorize for MPMSU)
Methanol poisoning treatment

Key Mnemonics: NMS vs Serotonin Syndrome, Opioid tolerance "CAD", CPZ side effects "ABCDE"

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