Home Drug Guide Lamotrigine

Drug Guide

Generic Name

Lamotrigine

Brand Names Lamictal, Lamictal CD, Lamictal XR, Lamictal ODT

Classification

Therapeutic: Anticonvulsant, Mood stabilizer

Pharmacological: Voltage-gated sodium channel inhibitor

FDA Approved Indications

  • Bipolar I disorder maintenance therapy
  • Partial seizures
  • Generalized seizures (including primary generalized tonic-clonic seizures)

Mechanism of Action

Lamotrigine stabilizes neuronal membranes by inhibiting voltage-sensitive sodium channels, which decreases the release of excitatory neurotransmitters like glutamate and aspartate, thereby exerting anticonvulsant and mood-stabilizing effects.

Dosage and Administration

Adult: Initial dose typically 25 mg once daily for 2 weeks, then titrated gradually based on response and tolerability.

Pediatric: Starting dose generally 0.3 mg/kg/day, titrated gradually.

Geriatric: Start at lower doses; titrate cautiously due to potential for increased sensitivity.

Renal Impairment: Adjust dose based on renal function; consult detailed dosing guidelines.

Hepatic Impairment: Use with caution; no specific dose adjustment provided, but monitor closely.

Pharmacokinetics

Absorption: Rapid and complete absorption from gastrointestinal tract.

Distribution: Approximately 55% bound to plasma proteins.

Metabolism: Metabolized mainly via conjugation with glucuronic acid; minimal hepatic oxidation.

Excretion: Excreted primarily in urine as metabolites.

Half Life: Approximately 25-33 hours in healthy adults; shorter in children.

Contraindications

  • Hypersensitivity to lamotrigine or other ingredients.
  • History of severe hypersensitivity reactions such as Stevens-Johnson syndrome.

Precautions

  • Risk of aseptic meningitis; monitoring required.
  • History of mood disorders or suicidality; caution advised.
  • Use with caution in patients with kidney or liver impairment.
  • Potential for serious skin reactions; initiate at low doses and titrate slowly.

Adverse Reactions - Common

  • Dizziness (Common)
  • Headache (Common)
  • Nausea (Common)
  • Somnolence (Common)
  • Rash (Uncommon)

Adverse Reactions - Serious

  • Stevens-Johnson syndrome (SJS) (Rare)
  • Toxic epidermal necrolysis (TEN) (Rare)
  • Aseptic meningitis (Rare)
  • Blood dyscrasias (Rare)
  • Suicidal thoughts or behavior (Potentially increased)

Drug-Drug Interactions

  • Valproic acid (increases lamotrigine levels, risk of SJS)
  • Oral contraceptives (may decrease lamotrigine levels)
  • Carbamazepine (may decrease lamotrigine levels)
  • Other enzyme inducers or inhibitors

Drug-Food Interactions

N/A

Drug-Herb Interactions

N/A

Nursing Implications

Assessment: Monitor for skin rash, neurological status, mood changes, CBC counts.

Diagnoses:

  • Risk for skin integrity impairment
  • Risk for neurological impairment

Implementation: Start at low dose, titrate gradually, monitor for adverse reactions.

Evaluation: Assess seizure control, mood stabilization, and adverse effects regularly.

Patient/Family Teaching

  • Take medication exactly as prescribed.
  • Report any skin rash, fever, sore throat, or blisters immediately.
  • Do not stop medication abruptly.
  • Use caution when operating machinery until response is known.
  • Inform about potential mood changes and suicidal thoughts.

Special Considerations

Black Box Warnings:

  • Serious dermatologic reactions such as Stevens-Johnson syndrome and toxic epidermal necrolysis

Genetic Factors: HLA-B extsuperscript*1502 allele may increase risk of SJS in some populations (e.g., Asians).

Lab Test Interference: May affect some laboratory tests, such as blood counts.

Overdose Management

Signs/Symptoms: Dizziness, ataxia, nystagmus, altered mental status.

Treatment: Supportive care; consider activated charcoal if ingestion is recent; hemodialysis may reduce plasma levels in overdose.

Storage and Handling

Storage: Stored at room temperature, 20-25°C (68-77°F).

Stability: Stable up to the expiration date when stored properly.

🛡️ 5 Critical Medication Safety Tips for Nurses

1

Triple-Check High-Risk Medications

Always have another nurse verify insulin, heparin, warfarin, and chemotherapy drugs. These "high-alert" medications cause the most serious errors. Check concentration, dose calculation, and pump settings twice.

2

Know Look-Alike, Sound-Alike Drugs

Common mix-ups: hydromorphone/morphine, Celebrex/Celexa, Zyprexa/Zyrtec. Always use BOTH generic and brand names, read labels twice, and use barcode scanning when available. One wrong letter can be fatal.

3

Assess Before AND After Giving Meds

Check vitals before cardiac meds, pain levels before analgesics, and blood glucose before insulin. Always reassess within 30 minutes to evaluate effectiveness and watch for adverse reactions.

4

Watch for Drug Interactions

Common dangerous combinations: warfarin + aspirin (bleeding), ACE inhibitors + potassium (hyperkalemia), digoxin + diuretics (toxicity). Always check drug interactions before administering new medications.

5

Educate Your Patients

Teach patients medication names, purposes, major side effects, and what to report. Informed patients catch errors and improve compliance. Always encourage questions - an educated patient is a safer patient.

⚡ Remember: When in doubt, don't give it out! It's always safer to double-check than regret later.

⚠️ Medical Disclaimer

This drug guide is for educational purposes only and is NOT intended for clinical use. Always consult current prescribing information, healthcare providers, and institutional protocols before administering any medication. Do not use this information for patient care decisions.