Hi I am preparing for neurosurgery and I want few things of neuropharmacology with antibiotics used in neurosurgery anti epileptics in neurosurgery anti edema agents , chemotherapy agents in neurosurgery and give me drug class, mechanism of action, side effects, special points and try to add as much as images overall and also use standard books Also give some imp drugs of neurology and also add doses of all drugs for different condition and different age grps

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Here is your comprehensive neurosurgery neuropharmacology guide, drawn from Bradley & Daroff's Neurology, Washington Manual, Goldman-Cecil Medicine, Tintinalli's Emergency Medicine, and Rosen's Emergency Medicine, supplemented with current guidelines.

🧠 Neuropharmacology for Neurosurgery — Complete Guide

PART 1 — ANTIBIOTICS IN NEUROSURGERY

1A. Surgical Prophylaxis

Standard Practice (ASHP/IDSA/SIS Guidelines):

For elective craniotomy, CSF-shunting procedures, and intrathecal pump implantation: Cefazolin is first-line; Clindamycin or Vancomycin for penicillin allergy.

🔵 CEFAZOLIN (1st-Generation Cephalosporin)

Feature	Details
Drug Class	1st-generation cephalosporin (β-lactam)
Mechanism	Inhibits bacterial cell wall synthesis by binding penicillin-binding proteins (PBPs), blocking transpeptidation of peptidoglycan
Spectrum	Gram-positive cocci (S. aureus, S. epidermidis — main SSI pathogens), some Gram-negatives
Dose — Adults	2 g IV (3 g if >120 kg) given within 60 min before incision; redose every 4 hours intraoperatively
Dose — Pediatric	30 mg/kg IV (max 2 g) within 60 min before incision
Duration	Single dose; discontinue within 24 hours of surgery end (no benefit to prolonged prophylaxis)
Side Effects	Hypersensitivity (rash, anaphylaxis <0.02%), C. difficile colitis (rare), phlebitis
Special Points	Does NOT cross intact BBB well — used for wound/bone prophylaxis, not CNS infection treatment; adequate CSF penetration only with inflamed meninges

🔵 VANCOMYCIN (Glycopeptide)

Feature	Details
Drug Class	Glycopeptide antibiotic
Mechanism	Binds D-Ala-D-Ala terminus of peptidoglycan precursors → blocks transglycosylation → inhibits cell wall synthesis
Spectrum	MRSA, MRSE, coagulase-negative staphylococci, Enterococcus
Dose — Adults (prophylaxis)	15–20 mg/kg IV (max 3 g), infused over 60–120 min, started 60–120 min before incision
Dose — Pediatric (prophylaxis)	15 mg/kg IV (max 750 mg/dose)
Dose — Adults (treatment — meningitis/ventriculitis)	15–20 mg/kg IV every 8–12 hours (target AUC/MIC 400–600)
Dose — Pediatric (treatment)	40–60 mg/kg/day IV divided every 6 hours
Intrathecal/Intraventricular	5–20 mg/day (for shunt infections/ventriculitis)
Side Effects	Red man syndrome (vancomycin flushing syndrome — slow infusion), nephrotoxicity, ototoxicity, DRESS
Special Points	Use when MRSA prevalence >10–20% or patient is MRSA carrier; target trough for CNS infection: 15–20 µg/mL; preferred for post-neurosurgical meningitis

🔵 MEROPENEM (Carbapenem) — for CNS Infections

Feature	Details
Drug Class	Carbapenem (β-lactam)
Mechanism	Binds multiple PBPs → inhibits cell wall synthesis; resistant to most β-lactamases
Spectrum	Broad: GN including Pseudomonas, Enterobacteriaceae, anaerobes, most GP
Dose — Adults (meningitis)	2 g IV every 8 hours (high-dose for CNS penetration)
Dose — Pediatric	40 mg/kg IV every 8 hours (max 2 g/dose)
Side Effects	Seizures (especially at high doses or renal failure), nausea, hepatotoxicity
Special Points	Drug of choice for post-neurosurgical Gram-negative meningitis (Acinetobacter, Pseudomonas); good CSF penetration with inflamed meninges

🔵 METRONIDAZOLE — for Anaerobic CNS Infections (Brain Abscess)

Feature	Details
Drug Class	Nitroimidazole
Mechanism	Reduced to cytotoxic intermediates inside anaerobic organisms → DNA strand breakage
Spectrum	Anaerobes, Bacteroides, protozoa
Dose — Adults	500 mg IV every 8 hours or 7.5 mg/kg IV every 6 hours
Dose — Pediatric	7.5 mg/kg IV/PO every 6 hours (max 500 mg/dose)
Side Effects	Metallic taste, peripheral neuropathy (prolonged use), disulfiram-like reaction with alcohol, neurotoxicity (encephalopathy, cerebellar syndrome at high doses)
Special Points	Excellent CNS penetration — crosses BBB regardless of inflammation; cornerstone in brain abscess treatment (combined with ceftriaxone or penicillin)

🔵 CEFTRIAXONE — for Bacterial Meningitis

Feature	Details
Drug Class	3rd-generation cephalosporin
Mechanism	Inhibits PBPs → blocks peptidoglycan cross-linking
Spectrum	S. pneumoniae, N. meningitidis, Gram-negatives, H. influenzae
Dose — Adults	2 g IV every 12 hours (meningitis)
Dose — Children >1 month	100 mg/kg/day IV divided every 12–24 hours (max 4 g/day)
Dose — Neonates	50–100 mg/kg/day IV once daily
Side Effects	Biliary sludging, hypersensitivity, Clostridium difficile
Special Points	Always combine with dexamethasone 0.15 mg/kg IV every 6 hours for 4 days given 15–20 min BEFORE first antibiotic dose to reduce inflammatory cytokine release and hearing loss

🔵 LINEZOLID — for MRSA/VRE CNS infections

Feature	Details
Drug Class	Oxazolidinone
Mechanism	Binds 23S rRNA of 50S ribosomal subunit → inhibits initiation complex formation → inhibits protein synthesis
Dose — Adults	600 mg IV/PO every 12 hours
Dose — Pediatric	10 mg/kg IV/PO every 8 hours (max 600 mg/dose)
Side Effects	Thrombocytopenia (>2 weeks use), serotonin syndrome (with SSRIs/MAOIs), optic neuritis, peripheral neuropathy
Special Points	Excellent CNS penetration (CSF:plasma ratio ~0.7); used when vancomycin fails or for VRE ventriculitis

PART 2 — ANTIEPILEPTIC DRUGS (AEDs) IN NEUROSURGERY

Seizures occur in 20–40% of brain tumor patients and up to 15% post-craniotomy. Seizure prophylaxis is crucial peri-operatively.

🟢 LEVETIRACETAM (Keppra) — Preferred in Neurosurgery

Feature	Details
Drug Class	Pyrrolidine derivative — synaptic vesicle modulator
Mechanism	Binds SV2A (synaptic vesicle glycoprotein 2A) → modulates neurotransmitter release; also inhibits Ca²⁺ channels and reverses inhibition of GABA and glycine-gated currents
Dose — Adults (prophylaxis)	500–1000 mg PO/IV every 12 hours
Dose — Adults (status epilepticus)	1000–3000 mg IV over 15 min (loading), then 1000–3000 mg/day maintenance
Dose — Children (2–17 y)	10–20 mg/kg/day divided BID, up to max 60 mg/kg/day
Dose — Neonates/Infants	10 mg/kg/day, titrate up to 40–60 mg/kg/day
Side Effects	Behavioral changes (irritability, aggression — "Keppra rage"), somnolence, dizziness, infection risk
Special Points	⭐ Drug of choice in neurosurgery — no hepatic enzyme induction, no protein binding issues, no CYP interactions; safe with steroids, chemotherapy, immunosuppressants; renally cleared (adjust in renal failure); available as IV formulation; bioequivalent IV=PO

🟢 PHENYTOIN / FOSPHENYTOIN

Feature	Details
Drug Class	Hydantoin
Mechanism	Blocks voltage-gated Na⁺ channels (use-dependent) → stabilizes neuronal membranes; prolongs refractory period
Dose — Adults (loading)	15–20 mg/kg IV at ≤50 mg/min (phenytoin) or 150 mg PE/min (fosphenytoin)
Dose — Adults (maintenance)	300–400 mg/day PO/IV divided TID or once daily (extended release)
Dose — Children (loading)	15–20 mg/kg IV at ≤1–3 mg/kg/min (phenytoin)
Dose — Children (maintenance)	4–8 mg/kg/day divided BID–TID
Therapeutic level	10–20 µg/mL (free level: 1–2 µg/mL)
Side Effects	Cardiac arrhythmia/hypotension (IV rapid infusion), ataxia, nystagmus, gingival hyperplasia, hirsutism, osteoporosis, SJS/TEN, purple glove syndrome (IV extravasation), zero-order kinetics (saturable)
Special Points	IV phenytoin must be given in normal saline (precipitates in dextrose); NOT compatible with most IV solutions; fosphenytoin is water-soluble prodrug — can be given IM, faster infusion; enzyme inducer (↓ steroids, ↓ chemotherapy levels); narrow therapeutic window; NOT first-line anymore due to interactions

🟢 VALPROATE (Sodium Valproate / Valproic Acid)

Feature	Details
Drug Class	Short-chain branched fatty acid
Mechanism	Na⁺ channel blockade + enhances GABA (↑ GABA synthesis, ↓ GABA degradation) + T-type Ca²⁺ channel inhibition
Dose — Adults (status epilepticus)	20–40 mg/kg IV at 3–6 mg/kg/min loading; maintenance 10–15 mg/kg/day divided BID–TID
Dose — Adults (chronic)	500–2000 mg/day PO divided BID–TID; serum level: 50–100 µg/mL
Dose — Children	15–45 mg/kg/day divided BID–TID
Side Effects	Hepatotoxicity (potentially fatal — check LFTs), pancreatitis, thrombocytopenia, weight gain, tremor, hair loss, teratogenicity (neural tube defects — CONTRAINDICATED in pregnancy/women of childbearing age), hyperammonemia
Special Points	Broad-spectrum AED — covers generalized, focal, myoclonic, absence; inhibits CYP2C9 → ↑ phenytoin levels; good for brain tumor seizures but interact with temozolomide; AVOID in liver disease

🟢 LACOSAMIDE

Feature	Details
Drug Class	Functionalized amino acid
Mechanism	Enhances slow inactivation of voltage-gated Na⁺ channels (distinct from phenytoin which blocks fast inactivation); also binds CRMP-2
Dose — Adults	200–400 mg/day PO/IV divided BID; loading: 200–400 mg IV over 15–60 min
Dose — Children (≥4 years)	2–8 mg/kg/day divided BID (max 400 mg/day)
Side Effects	Dizziness, diplopia, PR interval prolongation (use caution in cardiac patients), ataxia
Special Points	Increasingly used peri-operatively; fewer drug interactions than phenytoin; IV formulation available; good option when benzodiazepines/phenytoin/levetiracetam have failed

🟢 CARBAMAZEPINE

Feature	Details
Drug Class	Iminostilbene
Mechanism	Blocks fast Na⁺ channels (use-dependent); also blocks NMDA receptors and adenosine receptors
Dose — Adults	200 mg PO BID, titrate to 400–1200 mg/day divided TID–QID; serum level: 4–12 µg/mL
Dose — Children	10–20 mg/kg/day divided TID–QID
Side Effects	SJS/TEN (HLA-B1502 in Asian patients — screen before use*), hyponatremia (SIADH), aplastic anemia, agranulocytosis, diplopia, ataxia
Special Points	Strong CYP3A4 inducer → reduces levels of many drugs including corticosteroids, immunosuppressants, OCP; auto-induction (induces its own metabolism); used in trigeminal neuralgia (drug of choice) at 200–1200 mg/day

🟢 STATUS EPILEPTICUS PROTOCOL (Tintinalli/WHO-based)

Time	Drug	Adult Dose	Pediatric Dose
0–5 min (stabilization)	Glucose + thiamine	Thiamine 100 mg IV first if alcoholism suspected	—
5–10 min (1st line)	Lorazepam	0.1 mg/kg IV (max 4 mg/dose), repeat once	0.05–0.1 mg/kg IV (max 4 mg)
5–10 min (prehospital/IM)	Midazolam	10 mg IM (>40 kg)	0.2 mg/kg IM (max 10 mg)
20–40 min (2nd line)	Levetiracetam	60 mg/kg IV (max 4500 mg) over 10 min	40–60 mg/kg IV
20–40 min (alternative)	Fosphenytoin	20 mg PE/kg IV at 150 mg PE/min	20 mg PE/kg IV at 3 mg PE/kg/min
20–40 min (alternative)	Valproate	40 mg/kg IV (max 3000 mg) over 10 min	20–40 mg/kg IV
40–60 min (3rd line/refractory)	Propofol	1–2 mg/kg IV bolus, then 2–10 mg/kg/hr infusion	Avoid in children (<16 y) for prolonged sedation
40–60 min (refractory)	Midazolam infusion	0.2 mg/kg bolus, then 0.05–2 mg/kg/hr	0.15–0.2 mg/kg bolus, then 0.06–1 mg/kg/hr
40–60 min (refractory)	Pentobarbital	5–15 mg/kg IV loading, then 0.5–5 mg/kg/hr	Same

PART 3 — ANTI-EDEMA AGENTS IN NEUROSURGERY

Mechanism Overview — Vasogenic vs Cytotoxic Edema

Osmotic Therapy Mechanism — Vasogenic Edema

🔴 MANNITOL (Osmotic Agent)

Feature	Details
Drug Class	Osmotic diuretic
Mechanism	Creates osmotic gradient across BBB → draws water from brain interstitium into intravascular compartment → reduces brain volume and ICP. Also reduces blood viscosity → ↑ CBF → autoregulation → cerebral vasoconstriction → ↓ ICP. Short-acting rheological effect (onset 15–30 min)
Dose — Adults	0.25–1 g/kg IV over 15–20 min; may repeat every 4–6 hours; maximum 2 g/kg per episode
Dose — Pediatric	0.25–1 g/kg IV over 20–30 min; max 2 g/kg
Concentration used	20% solution (200 mg/mL)
Monitoring	Serum osmolality (target <320 mOsm/kg); osmolar gap (stop if >20); urine output; BUN/creatinine
Side Effects	Rebound ICP (osmolar equilibration), hypovolemia, electrolyte disturbances (hyponatremia → hypernatremia), renal failure (at high doses), pulmonary edema (heart failure patients)
Special Points	Drug of choice for acute ICP elevation; use a filter during infusion (crystals can form); use cautiously in renal failure or CHF; in Rosen's/Tintinalli: combined with head elevation 30°, hyperventilation (PCO₂ 30–35 mmHg), and sedation for ICP management ladder

🔴 HYPERTONIC SALINE (HTS)

Feature	Details
Drug Class	Osmotic agent
Mechanism	Increases serum osmolality → osmotic gradient draws water from brain into blood; avoids mannitol's diuresis; also has immunomodulatory and BBB-stabilizing effects
Formulations	3% NaCl (most common), 7.5%, 23.4%
Dose — Adults (3%)	250–500 mL IV bolus; serum Na target: 145–155 mEq/L
Dose — Adults (23.4%)	30–60 mL IV over 10 min for herniation (through central line only)
Dose — Pediatric	3% NaCl 3–5 mL/kg IV over 15–20 min
Target	Serum sodium 145–155 mEq/L; serum osmolality 300–320 mOsm/kg
Side Effects	Hypernatremia, hypokalemia, central pontine myelinolysis (if corrected too rapidly), phlebitis (hypertonic via peripheral line)
Special Points	Preferred over mannitol when patient is hypovolemic, hemodynamically unstable, or has renal failure; no osmotic diuresis → maintains volume; continuous infusion of 3% NaCl 0.5–1 mL/kg/hr for sustained ICP control; Neurocritical Care Society (2020) guidelines cannot make specific dose recommendation

🔴 DEXAMETHASONE (Corticosteroid — for Vasogenic Edema)

Feature	Details
Drug Class	Synthetic glucocorticoid
Mechanism	Binds glucocorticoid receptors → ↓ VEGF expression → reduces BBB permeability → reduces vasogenic edema around tumors; also ↓ prostaglandins and cytokines
Dose — Adults (brain tumor edema)	10 mg IV loading, then 4 mg IV/PO every 6 hours; taper over weeks
Dose — Pediatric (brain tumor)	0.5–1 mg/kg/day divided every 6 hours (max 10 mg/dose)
Dose — Bacterial meningitis	0.15 mg/kg IV every 6 hours for 4 days (give BEFORE first antibiotic dose) — Neurocritical Care Society Grade A
Dose — Spinal cord injury (historical, now controversial)	NASCIS protocol: 30 mg/kg IV over 15 min, then 5.4 mg/kg/hr for 23–47 hours — NOT recommended by current ACS guidelines
Side Effects	Hyperglycemia (impairs wound healing), immunosuppression (↑ PCP risk), Cushing's syndrome, psychiatric effects (steroid psychosis), avascular necrosis of femoral head, peptic ulcer, insomnia
Special Points	Only effective for VASOGENIC edema (tumor, abscess, radiation) — NOT for cytotoxic edema (stroke, TBI); ⚠️ Do NOT use in PCNSL before biopsy — can cause tumor lysis and false-negative biopsy ("ghost tumor/vanishing tumor"); avoid in traumatic brain injury (CRASH trial showed ↑ mortality)

PART 4 — CHEMOTHERAPY IN NEUROSURGERY

4A. Glioblastoma (GBM) — Stupp Protocol

MGMT Methylation and Temozolomide Response

🟡 TEMOZOLOMIDE (TMZ) — Backbone of GBM Treatment

Feature	Details
Drug Class	Alkylating agent (imidazotetrazine derivative)
Mechanism	Spontaneously converted to MTIC at physiological pH → methylates guanine at O6 position → O6-methylguanine → mispairing with thymine → DNA double-strand breaks → apoptosis. MGMT enzyme reverses this — MGMT methylation = no repair = better response
Dose — Concurrent phase	75 mg/m²/day PO daily during radiotherapy (42–49 days)
Dose — Adjuvant phase	150–200 mg/m²/day PO for 5 days every 28 days × 6 cycles
Pediatric dose	150–200 mg/m²/day × 5 days per cycle (same protocol adapted)
Side Effects	Myelosuppression (lymphopenia — monitor CBC), nausea/vomiting, fatigue, thrombocytopenia, opportunistic infections (PCP pneumonia — give TMP-SMX prophylaxis), hepatotoxicity
Special Points	Oral bioavailability ~100% (can be given with or without food); MGMT promoter methylation is predictive biomarker — methylated = better response (50% vs 14% benefit); crosses BBB well; concurrent PCP prophylaxis with cotrimoxazole (trimethoprim 160 mg + sulfamethoxazole 800 mg PO 3×/week)

(Source: Washington Manual of Medical Therapeutics; Grainger & Allison's Diagnostic Radiology — GBM section; Goldman-Cecil Medicine)

🟡 LOMUSTINE (CCNU) — for Recurrent GBM

Feature	Details
Drug Class	Alkylating agent (nitrosourea)
Mechanism	Alkylates DNA (O6-guanine, N1-adenine, N3-cytosine) + carbamylates proteins → inhibits DNA repair and replication; highly lipophilic → excellent CNS penetration
Dose — Adults	130 mg/m² PO every 6 weeks (single oral dose)
Dose — Pediatric	75–130 mg/m² PO every 6 weeks
Side Effects	Severe delayed myelosuppression (nadir at 4–6 weeks — cumulative), pulmonary fibrosis (cumulative >1000 mg/m²), hepatotoxicity, nausea/vomiting
Special Points	Excellent lipid solubility → crosses BBB; monitor CBC weekly; avoid in patients with compromised bone marrow; cumulative pulmonary toxicity — baseline PFTs; used in MGMT-unmethylated recurrent GBM or combined with temozolomide

🟡 CARMUSTINE (BCNU) / GLIADEL WAFER

Feature	Details
Drug Class	Alkylating agent (nitrosourea)
Mechanism	Same as lomustine — DNA/RNA alkylation and protein carbamylation; bifunctional → crosslinks DNA strands
IV Dose — Adults	150–200 mg/m² IV every 6 weeks (or 75–100 mg/m²/day × 2 days every 6 weeks)
Gliadel Wafer (local)	3.85% BCNU biodegradable polymer wafers — up to 8 wafers placed in tumor resection cavity at surgery; each wafer delivers 7.7 mg BCNU = total ~61.6 mg
Side Effects	Systemic: myelosuppression (delayed, cumulative), pulmonary toxicity, renal toxicity, venous occlusive disease. Wafer: cerebral edema, wound infection, CSF leak
Special Points	Wafer provides local delivery bypassing BBB; approved for GBM at initial surgery and recurrence; reduces systemic toxicity; caution — wafers should not be used with CSF leak (drug disseminates)

🟡 BEVACIZUMAB (Anti-VEGF)

Feature	Details
Drug Class	Humanized monoclonal antibody (anti-VEGF-A)
Mechanism	Binds all isoforms of VEGF-A → prevents binding to VEGFR-1 and VEGFR-2 → inhibits angiogenesis → reduces tumor vascularity and BBB permeability → ↓ edema (potent steroid-sparing effect)
Dose — Adults (recurrent GBM)	10 mg/kg IV every 2 weeks
Dose — Pediatric	10–15 mg/kg IV every 2–3 weeks (pediatric CNS tumors)
Side Effects	Hypertension, thromboembolism (DVT/PE), hemorrhage (impaired wound healing — hold 28 days before surgery), proteinuria, GI perforation, fistula formation, reversible posterior leukoencephalopathy syndrome (RPLS)
Special Points	Steroid-sparing — dramatically reduces vasogenic edema; used for radiation necrosis; ⚠️ hold 4–6 weeks before and after surgery (wound healing); response on MRI can be misleading ("pseudoresponse" — T1 enhancement decreases but disease may progress on T2/FLAIR); approved for recurrent GBM; NF2 vestibular schwannoma (10 mg/kg IV every 2 weeks)

🟡 TUMOR TREATING FIELDS (TTFields — Optune)

Feature	Details
Mechanism	Noninvasive alternating electric fields (200 kHz) → disrupt mitotic spindle → anti-mitotic effect on dividing tumor cells
Use	Concurrent with maintenance TMZ in newly diagnosed GBM (MGMT-methylated and unmethylated)
Dose	Worn ≥18 hours/day continuously
Side Effects	Scalp dermatitis at electrode sites, scalp discomfort; minimal systemic effects
Special Points	EF-14 trial showed improved overall survival from 16 to 20.9 months

4B. Brain Metastases

🟡 WHOLE-BRAIN RADIATION + STEROID-SPARING

Dexamethasone for edema (same dosing as above)
Memantine 10 mg PO BID with WBRT to reduce neurocognitive effects

🟡 TARGETED THERAPY (Lung/Breast/Melanoma Mets)

Drug	Target	Dose
Osimertinib	EGFR (NSCLC mets)	80 mg PO daily
Alectinib	ALK (NSCLC mets)	600 mg PO BID
Dabrafenib + Trametinib	BRAF V600E (melanoma)	150 mg PO BID + 2 mg PO daily
Trastuzumab emtansine	HER2 (breast mets)	3.6 mg/kg IV every 21 days

PART 5 — IMPORTANT NEUROLOGY DRUGS

5A. Parkinson's Disease

🟣 LEVODOPA + CARBIDOPA (Sinemet)

Feature	Details
Class	Dopamine precursor + peripheral decarboxylase inhibitor
Mechanism	Levodopa crosses BBB via L-amino acid transporter → converted to dopamine by DOPA decarboxylase centrally. Carbidopa inhibits peripheral DOPA decarboxylase → ↓ peripheral conversion → ↑ CNS availability, ↓ nausea
Dose (adults)	Start carbidopa/levodopa 25/100 mg PO TID; usual dose range 300–1200 mg levodopa/day divided TID–QID
Elderly	Start with 12.5/50 mg TID and titrate slowly
Side Effects	Dyskinesias (↑ with duration of use), on-off fluctuations, nausea, orthostatic hypotension, psychosis/hallucinations
Special Points	Gold standard for motor symptoms; take on empty stomach (amino acids compete); never abruptly stop (NMS risk); ratio carbidopa:levodopa = 1:4 or 1:10; extended-release (Sinemet CR) for smoothing off-periods

🟣 DOPAMINE AGONISTS — Ropinirole, Pramipexole, Rotigotine

Feature	Details
Class	Non-ergot dopamine receptor agonists (D2/D3)
Mechanism	Directly stimulate D2/D3 receptors in striatum → bypass degenerating presynaptic dopaminergic neurons
Ropinirole	Start 0.25 mg PO TID; titrate to 3–24 mg/day
Pramipexole	Start 0.125 mg TID; titrate to 1.5–4.5 mg/day
Rotigotine	2–8 mg/24h transdermal patch
Side Effects	Impulse control disorders (gambling, hypersexuality), somnolence, leg edema, hallucinations (more than levodopa in elderly), nausea, postural hypotension
Special Points	Often used as monotherapy in younger patients (delay levodopa complications); renal dose adjustment for pramipexole

🟣 MAO-B INHIBITORS — Selegiline, Rasagiline

Feature	Details
Class	Monoamine oxidase B inhibitors
Mechanism	Inhibit MAO-B → ↓ dopamine catabolism in striatum → ↑ dopamine availability
Selegiline	5 mg PO BID (with breakfast and lunch)
Rasagiline	1 mg PO once daily (monotherapy or adjunct)
Side Effects	Insomnia (selegiline), hypertensive crisis with tyramine (cheese effect — minimal at therapeutic doses), serotonin syndrome (with SSRIs/TCAs)
Special Points	Mild neuroprotective effect theoretical; rasagiline has fewer interactions; avoid with meperidine

🟣 CATECHOL-O-METHYLTRANSFERASE (COMT) INHIBITORS — Entacapone, Tolcapone

Drug	Dose	Notes
Entacapone	200 mg PO with each levodopa dose (max 8 doses/day)	Peripheral COMT inhibition only; extends levodopa half-life by 30–50%; ↑ dyskinesia; orange/brown urine
Tolcapone	100–200 mg PO TID	Central + peripheral; ↑ risk hepatotoxicity (monitor LFTs monthly)

🟣 AMANTADINE

Feature	Details
Class	NMDA receptor antagonist / dopamine release enhancer
Mechanism	Blocks NMDA glutamate receptors → reduces dyskinesias; also enhances dopamine release and inhibits reuptake
Dose	100 mg PO BID (max 400 mg/day); reduce in renal failure
Side Effects	Livedo reticularis, ankle edema, hallucinations, anticholinergic effects
Special Points	⭐ Only drug approved for levodopa-induced dyskinesias; also used in influenza and as early PD monotherapy

5B. Multiple Sclerosis

🟣 METHYLPREDNISOLONE — for Acute Relapses

Feature	Details
Dose	1 g IV daily × 3–5 days (adults)
Mechanism	↓ inflammation → restores BBB integrity → speeds recovery
Note	Reduces duration of relapse but does NOT improve long-term outcome

🟣 KEY DISEASE-MODIFYING THERAPIES

Drug	Class	Mechanism	Dose	Key Side Effects
Interferon β-1a	Immunomodulator	↓ T-cell activation, ↓ BBB permeability	30 mcg IM weekly (Avonex) or 44 mcg SC 3×/week (Rebif)	Flu-like symptoms, injection reactions, depression, elevated LFTs
Glatiramer acetate	Immunomodulator	Antigen competition with MBP → shifts Th1→Th2	20 mg SC daily or 40 mg SC 3×/week	Injection site reactions, transient flushing/palpitations
Natalizumab	Anti-α4-integrin (mAb)	Blocks VLA-4 → prevents T-cell transmigration across BBB	300 mg IV every 4 weeks	PML (progressive multifocal leukoencephalopathy — JC virus; risk ↑ with anti-JCV Ab+, prior IS), hypersensitivity
Fingolimod	S1P receptor modulator	Sequesters lymphocytes in lymph nodes	0.5 mg PO daily	Bradycardia (1st dose monitoring), macular edema, lymphopenia, PML (rare), skin cancer
Ocrelizumab	Anti-CD20 (mAb)	Depletes B cells	300 mg IV × 2 doses (2 weeks apart), then 600 mg IV every 6 months	Infusion reactions, infections, PML (rare), ↑ breast cancer risk
Alemtuzumab	Anti-CD52	Depletes T and B lymphocytes	12 mg IV daily × 5 days (year 1), × 3 days (year 2)	Autoimmune disorders (thyroid, ITP, nephropathy), serious infections
Siponimod	S1P1/S1P5 modulator	Lymphocyte sequestration (SPMS-specific)	2 mg PO daily (after titration)	Bradycardia, macular edema, CYP2C9 genotyping required

5C. Migraine

Acute Treatment

Drug	Class	Dose (Adults)	Notes
Sumatriptan	5-HT1B/1D agonist (triptan)	50–100 mg PO; 6 mg SC; 20 mg intranasal	Contraindicated in hemiplegic migraine, CAD, uncontrolled HTN; do NOT use within 24h of ergotamine
Rizatriptan	Triptan	5–10 mg PO; max 30 mg/day	Reduce to 5 mg if on propranolol
Lasmiditan	5-HT1F agonist (ditán)	50–200 mg PO once	No vasoconstriction — safe in CVD; do not drive 8h after
Rimegepant / Ubrogepant	CGRP receptor antagonist (gepant)	75 mg PO (rimegepant); 50–100 mg PO (ubrogepant)	Safe in CV disease; rimegepant also used for prevention

Migraine Prevention

Drug	Dose	Special Notes
Propranolol	40–240 mg/day PO	First-line; contraindicated in asthma/COPD
Topiramate	50–100 mg/day PO divided BID	Cognitive impairment, weight loss, kidney stones, teratogenic (major birth defects)
Amitriptyline	25–75 mg PO at bedtime	Also for tension-type HA, neuropathic pain
Erenumab / Fremanezumab	Anti-CGRP/CGRPR mAb	70–140 mg SC monthly
Valproate	500–1500 mg/day	Avoid in women of childbearing age

5D. Myasthenia Gravis

Drug	Class	Dose	Notes
Pyridostigmine	AChE inhibitor	30–90 mg PO every 4–8 hours	Treatment of symptoms; overdose → cholinergic crisis
Prednisolone	Corticosteroid	1 mg/kg/day PO	Immunosuppression; may worsen initially
Azathioprine	Antimetabolite	2–3 mg/kg/day PO	Steroid-sparing; check TPMT before use
IVIG	Immunomodulation	2 g/kg IV over 2–5 days	Myasthenic crisis
Plasma exchange	Immunoadsorption	5–6 exchanges over 2 weeks	Pre-thymectomy, myasthenic crisis

5E. Alzheimer's Disease

Drug	Class	Dose	MOA
Donepezil	AChE inhibitor	5–10 mg PO at bedtime	↑ ACh in synaptic cleft
Rivastigmine	AChE inhibitor + BuChE	6–12 mg/day PO or 9.5–13.3 mg/24h patch	Also used in Parkinson's dementia
Memantine	NMDA antagonist	10 mg PO BID	Reduces excitotoxicity
Lecanemab	Anti-amyloid mAb	10 mg/kg IV every 2 weeks	Removes amyloid plaques; risk: ARIA (amyloid-related imaging abnormalities)

5F. Neuropathic Pain

Drug	Class	Dose	Notes
Gabapentin	α2δ subunit ligand	300–1200 mg PO TID	Start low; sedation, weight gain; renal dosing
Pregabalin	α2δ subunit ligand	75–300 mg PO BID	Faster titration; neuropathic pain, fibromyalgia
Duloxetine	SNRI	60–120 mg PO daily	Diabetic neuropathy, fibromyalgia
Amitriptyline	TCA	10–75 mg PO at bedtime	Neuropathic pain, PHN
Carbamazepine	Na⁺ channel blocker	200–1200 mg/day	Trigeminal neuralgia drug of choice
Oxcarbazepine	Na⁺ channel blocker	600–1800 mg/day	Better tolerated than carbamazepine for TGN

5G. Spasticity (Post-Stroke, SCI, MS)

Drug	Dose	MOA
Baclofen	5–80 mg/day PO divided TID–QID; intrathecal: 25–800 µg/day	GABA-B agonist → inhibits mono/polysynaptic reflexes
Tizanidine	2–36 mg/day PO divided TID–QID	Central α2-agonist → reduces spinal motor neuron excitability
Dantrolene	25–400 mg/day PO divided QID	Inhibits Ca²⁺ release from SR → reduces muscle contraction (NMS treatment)
Botulinum toxin A	100–400 units IM per treatment session	Blocks ACh release at NMJ → focal chemodenervation

SUMMARY TABLE — Drug Classes at a Glance

Category	First-Line Drug	Key Mechanism
Neurosurgical prophylaxis	Cefazolin	β-lactam → PBP blockade
Post-op meningitis	Vancomycin + Meropenem	Cell wall synthesis inhibition
Brain abscess	Ceftriaxone + Metronidazole	Cell wall + DNA strand breaks
Peri-op AED	Levetiracetam	SV2A binding → ↓ neurotransmitter release
Status epilepticus 1st	Lorazepam/Midazolam	GABA-A potentiation
Status epilepticus 2nd	Levetiracetam/Fosphenytoin/Valproate	Multiple mechanisms
Cerebral edema (acute)	Mannitol or HTS	Osmotic gradient
Tumor edema	Dexamethasone	↓ VEGF, ↓ BBB permeability
GBM chemotherapy	Temozolomide	O6-guanine alkylation
Anti-angiogenic	Bevacizumab	Anti-VEGF-A
Parkinson's	Levodopa/Carbidopa	Dopamine replacement
MS relapse	Methylprednisolone	Anti-inflammatory
MS prevention	Natalizumab/Ocrelizumab	Immune cell trafficking blockade
Migraine acute	Sumatriptan	5-HT1B/1D agonist
Neuropathic pain	Gabapentin/Pregabalin	α2δ subunit blockade

Sources: Bradley & Daroff's Neurology in Clinical Practice (9780323642613); Washington Manual of Medical Therapeutics (9781975190620); Goldman-Cecil Medicine (9780323930345); Tintinalli's Emergency Medicine (9781260019933); Rosen's Emergency Medicine (9780323757898); AES Antiseizure Medication Summary 2024; Neurocritical Care Society Cerebral Edema Guidelines 2020; ASHP/IDSA Surgical Prophylaxis Guidelines.This is a complete, exam-ready neuropharmacology reference for neurosurgery preparation. Here's a quick orientation of what's covered:

What's Inside

📋 5 Major Sections:

Antibiotics in Neurosurgery — Cefazolin (prophylaxis), Vancomycin (MRSA/post-op infection), Meropenem (Gram-negative meningitis), Metronidazole (brain abscess), Ceftriaxone (bacterial meningitis), Linezolid (VRE/refractory MRSA)
Antiepileptics — Levetiracetam ⭐ (preferred peri-op AED), Phenytoin/Fosphenytoin, Valproate, Lacosamide, Carbamazepine, plus the full Status Epilepticus 3-tier escalation protocol with time-based doses
Anti-Edema Agents — Mannitol (acute ICP — 0.25–1 g/kg IV), Hypertonic Saline (3% and 23.4%), Dexamethasone (vasogenic edema/tumor — NOT for TBI/cytotoxic edema) with critical contraindications
Chemotherapy — Temozolomide (Stupp protocol — 75 mg/m² concurrent, 150–200 mg/m² adjuvant), Lomustine, Carmustine/Gliadel wafer, Bevacizumab (anti-VEGF), Tumor Treating Fields, plus targeted therapy for brain metastases
Important Neurology Drugs — Parkinson's (Levodopa/Carbidopa, DA agonists, MAO-B inhibitors, Amantadine), MS (Natalizumab, Ocrelizumab, IFN-β, Fingolimod), Migraine (triptans, gepants, ditans, CGRP mAbs), Myasthenia, Alzheimer's, Neuropathic pain, Spasticity

⭐ Key Exam Points to Remember:

Levetiracetam > Phenytoin in neurosurgery (no enzyme induction, no CYP interactions)
Mannitol — stop if osmolar gap >20 or serum osm >320
Dexamethasone CONTRAINDICATED before PCNSL biopsy ("vanishing tumor")
MGMT methylation = better TMZ response
Bevacizumab — hold 4–6 weeks perioperatively (wound healing)
Ceftriaxone + Dexamethasone (before antibiotics) for bacterial meningitis

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