Trigeminal Neuralgia¶

DIAGNOSIS: Trigeminal Neuralgia ICD-10: G50.0 (Trigeminal neuralgia) SCOPE: Diagnosis, differentiation of classic (idiopathic) vs secondary TN (MS, tumor, vascular), medical and surgical management. Covers typical TN (TN1), atypical TN (TN2), and secondary TN.

STATUS: Draft - Pending Review

PRIORITY KEY: STAT = Immediate | URGENT = Within hours | ROUTINE = Standard | EXT = Extended/atypical cases | - = Not applicable to this setting

SECTION A: ACTION ITEMS¶

1. LABORATORY WORKUP¶

1A. Essential/Core Labs¶

Test	Rationale	Target Finding	ED	HOSP	OPD	ICU
CBC with differential	Baseline before carbamazepine (bone marrow suppression risk); exclude infection	Normal	STAT	ROUTINE	ROUTINE	-
CMP (comprehensive metabolic panel)	Baseline renal/hepatic function before carbamazepine; SIADH risk	Normal	STAT	ROUTINE	ROUTINE	-
HLA-B*1502 genotype	Screen Asian patients before carbamazepine/oxcarbazepine (SJS/TEN risk)	Negative	-	ROUTINE	ROUTINE	-

1B. Extended Workup (Second-line)¶

Test	Rationale	Target Finding	ED	HOSP	OPD	ICU
ESR, CRP	Inflammatory causes; giant cell arteritis if age >50 with atypical features	Normal	-	ROUTINE	ROUTINE	-
ANA, anti-dsDNA	SLE or connective tissue disease with trigeminal involvement	Negative	-	-	ROUTINE	-
Lyme antibodies	Endemic areas; if facial numbness or other cranial nerve involvement	Negative	-	-	ROUTINE	-
Vitamin B12	Deficiency can cause neuropathy	>300 pg/mL	-	ROUTINE	ROUTINE	-
TSH	Exclude thyroid dysfunction	Normal	-	ROUTINE	ROUTINE	-
Glucose (fasting) or HbA1c	Diabetes screening; diabetic neuropathy	FBG <126 mg/dL; HbA1c <6.5%	-	ROUTINE	ROUTINE	-

1C. Rare/Specialized (Refractory or Atypical)¶

Test	Rationale	Target Finding	ED	HOSP	OPD	ICU
CSF analysis (cell count, protein, oligoclonal bands)	MS suspected; atypical presentation	Normal or OCBs if MS	-	EXT	EXT	-
Anti-aquaporin-4 (NMO-IgG)	Neuromyelitis optica with trigeminal involvement	Negative	-	-	EXT	-
Paraneoplastic antibody panel	Atypical facial pain; occult malignancy	Negative	-	-	EXT	-
ACE level	Sarcoidosis with cranial nerve involvement	Normal	-	-	EXT	-

2. DIAGNOSTIC IMAGING & STUDIES¶

2A. Essential/First-line¶

Study	Timing	Target Finding	Contraindications	ED	HOSP	OPD	ICU
MRI Brain with trigeminal protocol (3T preferred; CISS/FIESTA sequences)	Initial workup	Neurovascular compression (SCA, AICA); rule out MS plaques, tumor, other structural cause	MRI-incompatible devices	URGENT	ROUTINE	ROUTINE	-
MRA Brain (circle of Willis)	If MRI suggests vascular compression	Confirm vascular loop (SCA, AICA) compressing trigeminal nerve	Same as MRI	-	ROUTINE	ROUTINE	-

2B. Extended¶

Study	Timing	Target Finding	Contraindications	ED	HOSP	OPD	ICU
MRI Brain with contrast	Tumor suspected; atypical presentation	Rule out schwannoma, meningioma, epidermoid cyst	Contrast allergy; renal impairment	-	ROUTINE	ROUTINE	-
MRI Spine (cervical/thoracic)	MS suspected; other neurological symptoms	Demyelinating lesions	MRI contraindications	-	ROUTINE	ROUTINE	-
CT Head	MRI contraindicated; acute presentation	Rule out mass, hemorrhage	None	STAT	-	-	-

2C. Rare/Specialized¶

Study	Timing	Target Finding	Contraindications	ED	HOSP	OPD	ICU
Trigeminal reflex testing (blink reflex, masseter reflex)	Sensory loss; atypical TN	Normal or abnormal R1/R2 latencies	None	-	-	EXT	-
Visual evoked potentials (VEPs)	MS suspected	Prolonged P100 latency if demyelinating	None	-	-	EXT	-
CT angiography	MRA non-diagnostic; surgical planning	Vascular anatomy for MVD	Contrast allergy; renal impairment	-	ROUTINE	EXT	-

3. TREATMENT¶

3A. Acute/Emergent¶

Treatment	Route	Indication	Dosing	Contraindications	Monitoring	ED	HOSP	OPD	ICU
Carbamazepine	PO	Severe acute TN flare requiring rapid loading	100 mg BID; 200 mg BID :: PO :: :: Start 100-200 mg BID; may increase by 100 mg q12h if severe; max 1200 mg/day	AV block; bone marrow suppression; concurrent MAOIs; HLA-B*1502 positive	CBC, sodium, LFTs at baseline; sodium q2-4wk initially	URGENT	URGENT	-	-
Oxcarbazepine	PO	Alternative if carbamazepine not tolerated; fewer drug interactions	150 mg BID; 300 mg BID :: PO :: :: Start 150-300 mg BID; may increase by 150-300 mg q3d if severe; max 1800 mg/day	Hypersensitivity; HLA-B*1502 positive	Sodium q2-4wk initially (higher SIADH risk than CBZ)	URGENT	URGENT	-	-
IV Fosphenytoin	IV	Status trigeminus (severe, refractory, continuous attacks); oral medications not tolerated	15 mg PE/kg IV :: IV :: :: 15 mg PE/kg IV load over 30 min; followed by phenytoin PO or IV 100 mg TID	Complete heart block; sinus bradycardia	Continuous cardiac monitoring; BP	STAT	STAT	-	-
Lidocaine 4% topical	TOP	Adjunctive for trigger point relief	Apply to trigger zone :: TOP :: :: Apply to trigger zone TID-QID PRN; temporary relief	None significant	None	URGENT	URGENT	ROUTINE	-

3B. Symptomatic Treatments (First-line)¶

Treatment	Route	Indication	Dosing	Contraindications	Monitoring	ED	HOSP	OPD	ICU
Carbamazepine (Tegretol)	PO	First-line for classic TN; strongest evidence	100 mg BID; 200 mg BID; 200 mg TID; 300 mg TID; 400 mg TID :: PO :: :: Start 100 mg BID; increase by 100 mg q3-7d; target 600-1200 mg/day divided BID-TID; max 1200 mg/day	AV block; bone marrow suppression; MAOIs; porphyria; HLA-B*1502 positive	CBC, sodium, LFTs at baseline, 4wk, 8wk, then q3-6mo; drug level if needed (4-12 mcg/mL)	-	ROUTINE	ROUTINE	-
Carbamazepine XR (Carbatrol, Tegretol-XR)	PO	Better tolerability with extended-release formulation	200 mg BID; 300 mg BID; 400 mg BID; 600 mg BID :: PO :: :: Start 200 mg BID; increase by 200 mg q1wk; max 1200 mg/day	Same as IR	Same as IR	-	ROUTINE	ROUTINE	-
Oxcarbazepine (Trileptal)	PO	First-line alternative; fewer drug interactions; similar efficacy	150 mg BID; 300 mg BID; 450 mg BID; 600 mg BID :: PO :: :: Start 150-300 mg BID; increase by 150-300 mg q1wk; target 600-1800 mg/day; max 1800 mg/day	Hypersensitivity; HLA-B*1502 positive	Sodium at baseline, 2wk, 4wk, then q3-6mo (SIADH more common than CBZ)	-	ROUTINE	ROUTINE	-

3C. Second-line/Refractory¶

Treatment	Route	Indication	Dosing	Contraindications	Monitoring	ED	HOSP	OPD	ICU
Baclofen	PO	Add-on to carbamazepine; or monotherapy if CBZ/OXC not tolerated	5 mg TID; 10 mg TID; 20 mg TID :: PO :: :: Start 5 mg TID; increase by 5 mg/dose q3d; target 30-80 mg/day divided TID; max 80 mg/day	Severe renal impairment	Sedation, dizziness; taper slowly to avoid withdrawal seizures	-	ROUTINE	ROUTINE	-
Lamotrigine	PO	Add-on therapy; refractory TN	25 mg daily; 50 mg daily; 50 mg BID; 100 mg BID :: PO :: :: Start 25 mg daily x2wk; then 50 mg daily x2wk; increase by 50 mg q2wk; target 200-400 mg/day	History of serious rash; concurrent valproate (reduce dose)	Rash (SJS risk - titrate slowly)	-	ROUTINE	ROUTINE	-
Gabapentin	PO	Add-on therapy; mild benefit as monotherapy	300 mg qHS; 300 mg TID; 600 mg TID; 900 mg TID :: PO :: :: Start 300 mg qHS; increase by 300 mg q3d; target 900-2400 mg/day divided TID; max 3600 mg/day	Severe renal impairment (dose adjust)	Sedation, dizziness, edema; reduce dose in renal impairment	-	ROUTINE	ROUTINE	-
Pregabalin	PO	Add-on therapy; possibly better tolerability than gabapentin	75 mg BID; 150 mg BID; 225 mg BID; 300 mg BID :: PO :: :: Start 75 mg BID; increase by 75-150 mg q1wk; target 150-600 mg/day; max 600 mg/day	Severe renal impairment (dose adjust)	Sedation, dizziness, weight gain, edema	-	ROUTINE	ROUTINE	-
Phenytoin	PO	Historical use; add-on if other agents fail	100 mg TID; 200 mg TID :: PO :: :: Start 100 mg TID; target 300-500 mg/day; adjust by levels	Complete heart block; porphyria	Drug level (10-20 mcg/mL); gingival hyperplasia; CBC	-	ROUTINE	ROUTINE	-
Botulinum toxin type A	SC	Refractory to oral medications; localized trigger zone	25-75 units :: SC :: :: 25-75 units subcutaneously into trigger zone; repeat q12wk	Infection at injection site; neuromuscular disease	Facial weakness, bruising	-	-	ROUTINE	-
Duloxetine	PO	Comorbid depression; neuropathic pain component	30 mg daily; 60 mg daily :: PO :: :: Start 30 mg daily x1wk; increase to 60 mg daily; max 120 mg/day	MAOIs; uncontrolled glaucoma; severe renal impairment	BP, serotonin syndrome signs	-	ROUTINE	ROUTINE	-
Pimozide	PO	Refractory cases; limited evidence	2 mg daily; 4 mg daily :: PO :: :: Start 2 mg daily; may increase to 4-8 mg daily; max 12 mg/day	QT prolongation; concurrent QT-prolonging drugs; Parkinson's	ECG (QTc); extrapyramidal symptoms	-	-	EXT	-

3D. Surgical/Interventional Therapies¶

Treatment	Route	Indication	Dosing	Pre-Treatment Requirements	Contraindications	Monitoring	ED	HOSP	OPD	ICU
Microvascular decompression (MVD)	Surgical	Classic TN with vascular compression on MRI; good surgical candidate	Open craniotomy :: Surgical :: :: Retromastoid craniectomy; Teflon felt between nerve and vessel; definitive treatment	MRI confirming vascular compression; cardiac clearance; anesthesia clearance	Poor surgical candidate; significant comorbidities; short life expectancy	Post-op neuro checks; hearing assessment; CSF leak	-	-	ROUTINE	-
Percutaneous glycerol rhizotomy	Surgical	Elderly; poor surgical candidate; MS-related TN; recurrence after MVD	Glycerol injection into Meckel's cave :: Percutaneous :: :: Inject 0.2-0.4 mL glycerol via foramen ovale under fluoroscopy	Coagulation studies; informed consent regarding numbness	Active infection; bleeding diathesis	Facial numbness (expected); corneal reflex; anesthesia dolorosa risk	-	-	ROUTINE	-
Percutaneous balloon compression	Surgical	V1 predominant TN (preserves corneal reflex); poor surgical candidate	Balloon compression :: Percutaneous :: :: Inflate balloon via foramen ovale for 60-120 seconds	Coagulation studies	Uncontrolled hypertension during procedure	Facial numbness; masseter weakness; corneal reflex	-	-	ROUTINE	-
Percutaneous radiofrequency thermocoagulation	Surgical	Poor surgical candidate; recurrence after other procedures	RF lesioning :: Percutaneous :: :: Create lesion via foramen ovale at affected division(s)	Coagulation studies; patient cooperation (awake procedure)	Cannot cooperate with awake procedure	Facial numbness; corneal reflex; anesthesia dolorosa risk	-	-	ROUTINE	-
Gamma Knife radiosurgery (GKRS)	Non-invasive	Poor surgical candidate; anticoagulated; MS-related TN; recurrence	70-90 Gy to root entry zone :: Non-invasive :: :: Single fraction to trigeminal root entry zone; effect delayed 1-3 months	MRI for targeting; stereotactic frame placement	Tumor causing TN (requires resection)	Delayed effect (weeks-months); facial numbness (10-30%); can repeat	-	-	ROUTINE	-
CyberKnife stereotactic radiosurgery	Non-invasive	Alternative to Gamma Knife; frameless option	60-75 Gy :: Non-invasive :: :: Frameless stereotactic radiosurgery to trigeminal root	MRI for targeting	Same as GKRS	Same as GKRS	-	-	EXT	-

4. OTHER RECOMMENDATIONS¶

4A. Referrals & Consults¶

Recommendation	ED	HOSP	OPD	ICU
Neurology referral for diagnosis confirmation, medication optimization, and long-term management	ROUTINE	ROUTINE	ROUTINE	-
Neurosurgery consultation for surgical evaluation if medication refractory or vascular compression on imaging	-	ROUTINE	ROUTINE	-
Pain management referral for multidisciplinary approach and interventional options	-	-	ROUTINE	-
Oral surgery or dentistry to rule out dental pathology mimicking TN	-	-	ROUTINE	-
Neuro-ophthalmology if V1 involvement with corneal reflex concerns	-	ROUTINE	ROUTINE	-
Psychiatry or psychology for coping strategies given chronic severe pain and depression risk	-	-	ROUTINE	-
Ophthalmology for corneal protection if reduced corneal sensation after procedure	-	ROUTINE	ROUTINE	-

4B. Patient Instructions¶

Recommendation	ED	HOSP	OPD
Avoid known triggers such as cold wind, touching face, eating, brushing teeth, or talking when possible	ROUTINE	ROUTINE	ROUTINE
Return immediately if facial weakness, hearing changes, or fever develop after procedure (may indicate serious complication)	-	ROUTINE	ROUTINE
Do not stop carbamazepine or oxcarbazepine abruptly as this may cause rebound pain or seizures	ROUTINE	ROUTINE	ROUTINE
Report any skin rash, mouth sores, or fever immediately (may indicate serious drug reaction SJS/TEN)	ROUTINE	ROUTINE	ROUTINE
Monitor for signs of low sodium (confusion, nausea, headache, muscle cramps) especially in first weeks on carbamazepine/oxcarbazepine	ROUTINE	ROUTINE	ROUTINE
Report any easy bruising, bleeding, or frequent infections (may indicate bone marrow suppression)	ROUTINE	ROUTINE	ROUTINE
Keep a pain diary to track triggers, severity, and medication effectiveness	-	ROUTINE	ROUTINE
Protect eye on affected side if corneal sensation reduced after surgery (use lubricating drops, protective eyewear)	-	ROUTINE	ROUTINE
Soft diet may reduce triggered attacks during flares	ROUTINE	ROUTINE	ROUTINE

4C. Lifestyle & Prevention¶

Recommendation	ED	HOSP	OPD
Avoid extreme cold or wind to face (use scarf or mask in cold weather)	-	ROUTINE	ROUTINE
Maintain good dental hygiene to prevent dental infections that may worsen or mimic TN	-	ROUTINE	ROUTINE
Stress reduction techniques (meditation, relaxation) as stress can exacerbate attacks	-	ROUTINE	ROUTINE
Use lukewarm water for face washing; avoid very cold water	-	ROUTINE	ROUTINE
Consider electric toothbrush with soft bristles to minimize trigger stimulation	-	-	ROUTINE
Eat softer foods during flare periods to reduce chewing-triggered attacks	-	ROUTINE	ROUTINE
Avoid alcohol which may interact with medications and worsen symptoms	-	ROUTINE	ROUTINE
Join TN support groups for coping strategies and emotional support	-	-	ROUTINE

SECTION B: REFERENCE¶

5. DIFFERENTIAL DIAGNOSIS¶

Alternative Diagnosis	Key Distinguishing Features	Tests to Differentiate
Dental pathology (pulpitis, periapical abscess, cracked tooth)	Constant aching pain; thermal sensitivity; localized to tooth; percussion tenderness	Dental exam and imaging; periapical X-rays
Temporomandibular joint disorder (TMD)	Jaw pain; clicking/popping; pain with chewing; muscle tenderness	TMJ exam; imaging if needed
Cluster headache	Severe unilateral orbital pain; autonomic symptoms (lacrimation, rhinorrhea, ptosis); lasts 15-180 min	Clinical history; no trigger by light touch
Short-lasting unilateral neuralgiform headache attacks (SUNCT/SUNA)	Very brief attacks (seconds); prominent autonomic features; no refractory period	Clinical features; MRI to rule out pituitary lesion
Persistent idiopathic facial pain (atypical facial pain)	Constant daily pain; poorly localized; no triggers; often psychological component	Diagnosis of exclusion; normal imaging
Postherpetic neuralgia	History of shingles in trigeminal distribution; constant burning pain; allodynia	History of vesicles; sensory loss in dermatome
Multiple sclerosis (secondary TN)	Younger age; bilateral TN; other neurological symptoms/signs; MS lesion on MRI	MRI brain/spine; CSF oligoclonal bands; evoked potentials
Trigeminal schwannoma	Progressive sensory loss; facial weakness; may have TN-like pain	MRI with contrast (enhancing mass at cerebellopontine angle)
Meningioma (skull base)	Progressive symptoms; may have cranial nerve palsies	MRI with contrast (dural-based enhancing mass)
Glossopharyngeal neuralgia	Pain in throat, ear, tongue; triggered by swallowing; similar shock-like quality	Clinical localization; pain in different distribution
Giant cell arteritis	Age >50; temporal headache; jaw claudication; elevated ESR/CRP	ESR, CRP, temporal artery biopsy
Trigeminal neuropathy	Constant numbness or pain; sensory loss on exam; not shock-like	Trigeminal reflex testing; MRI for cause

6. MONITORING PARAMETERS¶

Parameter	Frequency	Target/Threshold	Action if Abnormal	ED	HOSP	OPD	ICU
Pain severity (NRS 0-10, attack frequency)	Each visit	50%+ reduction; acceptable quality of life	Uptitrate medication; add second agent; consider surgery	-	ROUTINE	ROUTINE	-
CBC with differential (carbamazepine)	Baseline, 4wk, 8wk, then q3-6mo	WBC >3000; ANC >1500; platelets >100k	Hold medication if bone marrow suppression; hematology consult	-	ROUTINE	ROUTINE	-
Serum sodium (carbamazepine/oxcarbazepine)	Baseline, 2wk, 4wk, 8wk, then q3-6mo	>125 mEq/L	Fluid restriction; consider dose reduction or switch; severe hyponatremia requires urgent treatment	STAT	ROUTINE	ROUTINE	-
LFTs (AST, ALT, ALP)	Baseline, 4wk, 8wk, then q3-6mo	ALT/AST <3x ULN	Reduce dose or discontinue if significant elevation	-	ROUTINE	ROUTINE	-
Carbamazepine level	If toxicity suspected; adherence concerns; drug interactions	4-12 mcg/mL	Adjust dose accordingly	-	ROUTINE	ROUTINE	-
Skin exam	Each visit; urgent if rash	No rash	Discontinue immediately if rash with systemic symptoms (SJS risk)	STAT	ROUTINE	ROUTINE	-
Corneal reflex (if V1 TN or post-procedure)	Post-procedure; each follow-up	Intact	Eye protection; ophthalmology referral; lubricating drops	-	ROUTINE	ROUTINE	-
Neurological exam (sensory, motor, reflexes)	Each visit	Stable or improved; no new deficits	Re-evaluate diagnosis if progressive; repeat imaging	-	ROUTINE	ROUTINE	-
ECG (if on phenytoin, pimozide)	Baseline; with dose changes	Normal QTc (<470 ms men, <480 ms women)	Reduce dose or discontinue if QTc prolonged	-	ROUTINE	ROUTINE	-

7. DISPOSITION CRITERIA¶

Disposition	Criteria
Discharge home	Mild-moderate pain controlled with oral medications; able to eat and drink; no concerning symptoms; follow-up arranged
Admit to floor	Severe uncontrolled pain requiring IV medications or monitoring; unable to take oral medications; significant hyponatremia; new neurological deficits requiring workup
Admit to ICU	Rarely needed; severe hyponatremia with altered mental status; anaphylaxis to medication
Outpatient follow-up	2-4 weeks initially for medication titration and lab monitoring; then every 3-6 months when stable
Surgical referral criteria	Failed 2+ medications at adequate doses; intolerable side effects; vascular compression on MRI; patient preference for definitive treatment

8. EVIDENCE & REFERENCES¶

Recommendation	Evidence Level	Source
Carbamazepine first-line for classic TN	Class I, Level A	Cruccu et al. Eur J Neurol 2008 (EFNS Guidelines)
Oxcarbazepine effective alternative to carbamazepine	Class II, Level B	Di Stefano et al. Drugs 2018
HLA-B*1502 screening in Asian patients before carbamazepine	Class I, Level A	Chen et al. NEJM 2011
Baclofen add-on therapy for TN	Class III, Level C	Fromm et al. Arch Neurol 1984
Lamotrigine add-on for refractory TN	Class III, Level C	Zakrzewska et al. Pain 1997
MVD superior long-term outcomes	Class II, Level B	Barker et al. NEJM 1996
Gamma Knife for TN	Class II, Level B	Kondziolka et al. Stereotact Funct Neurosurg 2010
Percutaneous procedures for TN	Class III, Level C	Kanpolat et al. Neurosurgery 2001
Botulinum toxin for refractory TN	Class II, Level B	Shehata et al. J Headache Pain 2013
MRI with CISS/FIESTA for TN evaluation	Class II, Level B	Becker et al. Radiology 2010
ICHD-3 classification of TN	Expert consensus	Headache Classification Committee. Cephalalgia 2018
Comprehensive TN management review	Expert review	Cruccu et al. Nat Rev Neurol 2020

CHANGE LOG¶

v1.0 (January 27, 2026) - Initial template creation - Comprehensive coverage of classic and secondary TN - First-line (carbamazepine, oxcarbazepine) and second-line medical therapies - Surgical options including MVD, percutaneous procedures, and stereotactic radiosurgery - Structured dosing format for order sentence generation - PubMed citations with verified PMIDs

APPENDIX A: TN Classification (ICHD-3)¶

Classical Trigeminal Neuralgia (TN1)¶

Paroxysmal attacks lasting fraction of a second to 2 minutes
Unilateral distribution in trigeminal territory
Triggered by innocuous stimuli (light touch, chewing, talking, cold wind)
Electric shock-like, shooting, stabbing quality
Stereotyped in individual patient
No neurological deficit
MRI shows neurovascular compression OR is normal

Secondary Trigeminal Neuralgia¶

Same attack characteristics as classical TN
Underlying cause identified:
Multiple sclerosis (demyelinating lesion in root entry zone)
Tumor (schwannoma, meningioma, epidermoid)
Arteriovenous malformation
Other structural lesion
May have neurological deficit (sensory loss, weakness)

Idiopathic Trigeminal Neuralgia¶

Same attack characteristics as classical TN
No neurovascular compression on imaging
No identified secondary cause

Trigeminal Neuralgia with Concomitant Continuous Pain (TN2/Atypical)¶

Classical TN attacks PLUS
Continuous or near-continuous background pain in same distribution
More difficult to treat; may indicate central sensitization

APPENDIX B: Carbamazepine Drug Interactions¶

Major Interactions (Avoid or Adjust)¶

Drug/Class	Interaction	Management
MAOIs	Serotonin syndrome risk	Contraindicated
Nefazodone	Decreased CBZ metabolism; increased toxicity	Avoid
Oral contraceptives	Decreased efficacy (CYP3A4 induction)	Use alternative contraception
Warfarin	Decreased warfarin effect	Monitor INR closely
Doxycycline	Decreased doxycycline levels	Use alternative antibiotic
Macrolide antibiotics	Increased CBZ levels (CYP3A4 inhibition)	Monitor for toxicity
Azole antifungals	Increased CBZ levels	Monitor for toxicity
HIV protease inhibitors	Variable; decreased PI levels	Avoid or use with caution
Grapefruit juice	Increased CBZ absorption	Avoid

Autoinduction¶

Carbamazepine induces its own metabolism
Steady-state levels decrease 3-4 weeks after initiation
May need dose increase after 2-4 weeks

APPENDIX C: Surgical Option Comparison¶

Procedure	Pain-Free Rate (1yr)	Pain-Free Rate (5yr)	Recurrence	Numbness	Advantages	Disadvantages
MVD	90-95%	70-80%	20-30%	2-5%	Definitive; preserves sensation; lowest recurrence	Craniotomy; general anesthesia; serious complication risk (1-2%)
Gamma Knife	75-85%	50-60%	40-50%	10-30%	Non-invasive; outpatient	Delayed effect (weeks-months); higher recurrence
Glycerol rhizotomy	70-90%	50-60%	50-70%	50-70%	Percutaneous; quick recovery	High numbness rate; shorter duration
Balloon compression	80-90%	50-60%	40-60%	50-90%	Good for V1 TN; preserves corneal reflex	Numbness common; shorter duration
RF thermocoagulation	85-95%	50-60%	50-75%	80-100%	Precise targeting; immediate effect	Numbness universal; anesthesia dolorosa risk