Lamotrigine Tapering from 150 mg
Taper lamotrigine by reducing the dose by approximately 50% per week over at least 2 weeks when discontinuing. 1
FDA-Recommended Discontinuation Protocol
The FDA label for Lamictal explicitly states: "Discontinuation: Taper over a period of at least 2 weeks (approximately 50% dose reduction per week)." 1 This is the authoritative guidance that should direct your tapering strategy.
Practical Tapering Schedule from 150 mg
Following the FDA's 50% weekly reduction guideline:
- Week 1: Reduce to 75 mg daily
- Week 2: Reduce to 37.5 mg daily (or 25-50 mg if exact dosing unavailable)
- Week 3: Discontinue
If 37.5 mg tablets are unavailable, you can use 50 mg for week 2, then 25 mg for an additional few days before stopping.
Important Clinical Considerations
Withdrawal Phenomena
Be aware that lamotrigine withdrawal symptoms can occur and may be clinically significant. Research documents specific withdrawal reactions including:
- Psychomotor inhibition, anhedonia, tremor, tachycardia, and hyperhydrosis when stopped abruptly 2
- End-of-dose emergent symptoms (anxiety, emotional lability, irritability) occurring 1-2 hours before the next scheduled dose, even on stable dosing 3
These symptoms typically resolve spontaneously within days but can cause marked subjective distress.
When Slower Tapering May Be Warranted
While the FDA mandates a minimum 2-week taper, consider extending the taper over 4-6 weeks or longer if:
- The patient has been on lamotrigine for an extended period (months to years)
- The patient is particularly sensitive to medication changes
- There is a history of withdrawal symptoms from other CNS-active medications
- The patient experiences emergence of mood symptoms or anxiety during the taper
In these cases, reduce by 25 mg every 1-2 weeks rather than 50% weekly.
Critical Safety Warning
Never restart lamotrigine after discontinuation due to rash unless benefits clearly outweigh risks. 1 The risk of serious, life-threatening rash (Stevens-Johnson syndrome, toxic epidermal necrolysis) is substantially increased with rechallenge after a drug-related rash.
Drug Interaction Considerations
If the patient is taking valproate, carbamazepine, phenytoin, phenobarbital, or estrogen-containing contraceptives, be aware these significantly alter lamotrigine metabolism 1. However, during discontinuation, this is less critical than during initiation—just maintain the 2-week minimum taper regardless of concomitant medications.
Monitoring During Taper
Watch for:
- Seizure breakthrough (if used for epilepsy)
- Mood destabilization (if used for bipolar disorder)
- Withdrawal symptoms (anxiety, irritability, tremor, autonomic symptoms)
- Any new rash (though this is primarily a concern during initiation/escalation, not tapering)