Formulary
Lamotrigine: Indications, Dosing, Side Effects and Interactions
Lamotrigine clinical drug profile including indications, dosing, side effects, cautions and interactions.
MedNext Academy | 11 min read
Lamotrigine: Indications, Dosing, Side Effects and Interactions
Lamotrigine clinical drug profile including indications, dosing, side effects, cautions and interactions.
Indications and dose
**Monotherapy of focal seizures,Monotherapy of primary and secondary generalised tonic-clonic seizures,Monotherapy of seizures associated with Lennox-Gastaut syndrome**
- **Child** (By Mouth): 12-17 years Initially 25 mg once daily for 14 days, then increased to 50 mg once daily for further 14 days, then increased in steps of up to 100 mg every 7-14 days; maintenance 100-200 mg daily in 1-2 divided doses; increased if necessary up to 500 mg daily, dose titration should be repeated if restarting after interval of more than 5 days.
- **Adult** (By Mouth): Initially 25 mg once daily for 14 days, then increased to 50 mg once daily for further 14 days, then increased in steps of up to 100 mg every 7-14 days; maintenance 100-200 mg daily in 1-2 divided doses; increased if necessary up to 500 mg daily, dose titration should be repeated if restarting after interval of more than 5 days.
**Adjunctive therapy of focal seizures with valproate,Adjunctive therapy of primary and secondary generalised tonic-clonic seizures with valproate,Adjunctive therapy of seizures associated with Lennox-Gastaut syndrome with valproate**
- **Child** (By Mouth): 12-17 years Initially 25 mg once daily on alternate days for 14 days, then 25 mg once daily for further 14 days, then increased in steps of up to 50 mg every 7-14 days; maintenance 100-200 mg daily in 1-2 divided doses, dose titration should be repeated if restarting after interval of more than 5 days.
- **Adult** (By Mouth): Initially 25 mg once daily on alternate days for 14 days, then 25 mg once daily for further 14 days, then increased in steps of up to 50 mg every 7-14 days; maintenance 100-200 mg daily in 1-2 divided doses, dose titration should be repeated if restarting after interval of more than 5 days.
**Adjunctive therapy of focal seizures (with enzyme inducing drugs) without valproate,Adjunctive therapy of primary and secondary generalised tonic-clonic seizures (with enzyme inducing drugs) without valproate,Adjunctive therapy of seizures associated with Lennox-Gastaut syndromes (with enzyme inducing drugs) without valproate**
- **Child** (By Mouth): 12-17 years Initially 50 mg once daily for 14 days, then 50 mg twice daily for further 14 days, then increased in steps of up to 100 mg every 7-14 days; maintenance 200-400 mg daily in 2 divided doses, increased if necessary up to 700 mg daily, dose titration should be repeated if restarting after interval of more than 5 days.
- **Adult** (By Mouth): Initially 50 mg once daily for 14 days, then 50 mg twice daily for further 14 days, then increased in steps of up to 100 mg every 7-14 days; maintenance 200-400 mg daily in 2 divided doses, increased if necessary up to 700 mg daily, dose titration should be repeated if restarting after interval of more than 5 days.
**Adjunctive therapy of focal seizures (without enzyme inducing drugs) without valproate,Adjunctive therapy of primary and secondary generalised tonic-clonic seizures (without enzyme inducing drugs) without valproate,Adjunctive therapy of seizures associated with Lennox-Gastaut syndromes (without enzyme inducing drugs) without valproate**
- **Child** (By Mouth): 12-17 years Initially 25 mg once daily for 14 days, then increased to 50 mg once daily for further 14 days, then increased in steps of up to 100 mg every 7-14 days; maintenance 100-200 mg daily in 1-2 divided doses, dose titration should be repeated if restarting after interval of more than 5 days.
- **Adult** (By Mouth): Initially 25 mg once daily for 14 days, then increased to 50 mg once daily for further 14 days, then increased in steps of up to 100 mg every 7-14 days; maintenance 100-200 mg daily in 1-2 divided doses, dose titration should be repeated if restarting after interval of more than 5 days.
**Monotherapy or adjunctive therapy of bipolar disorder (without enzyme inducing drugs) without valproate**
- **Adult** (By Mouth): Initially 25 mg once daily for 14 days, then 50 mg daily in 1-2 divided doses for further 14 days, then 100 mg daily in 1-2 divided doses for further 7 days; maintenance 200 mg daily in 1-2 divided doses, patients stabilised on lamotrigine for bipolar disorder may require dose adjustments if other drugs are added to or withdrawn from their treatment regimens-consult product literature, dose titration should be repeated if restarting after interval of more than 5 days; maximum 400 mg per day.
**Adjunctive therapy of bipolar disorder with valproate**
- **Adult** (By Mouth): Initially 25 mg once daily on alternate days for 14 days, then 25 mg once daily for further 14 days, then 50 mg daily in 1-2 divided doses for further 7 days; maintenance 100 mg daily in 1-2 divided doses, patients stabilised on lamotrigine for bipolar disorder may require dose adjustments if other drugs are added to or withdrawn from their treatment regimens-consult product literature, dose titration should be repeated if restarting after interval of more than 5 days; maximum 200 mg per day.
**Adjunctive therapy of bipolar disorder (with enzyme inducing drugs) without valproate**
- **Adult** (By Mouth): Initially 50 mg once daily for 14 days, then 50 mg twice daily for further 14 days, then increased to 100 mg twice daily for further 7 days, then increased to 150 mg twice daily for further 7 days; maintenance 200 mg twice daily, patients stabilised on lamotrigine for bipolar disorder may require dose adjustments if other drugs are added to or withdrawn from their treatment regimens-consult product literature, dose titration should be repeated if restarting after interval of more than 5 days.
**Monotherapy of focal seizures, Monotherapy of primary and secondary generalised tonic-clonic seizures, Monotherapy of seizures associated with Lennox-Gastaut syndrome for lamotrigine**
- **Child 12-17 years** (By mouth): Initially 25 mg once daily for 14 days, then increased to 50 mg once daily for further 14 days, then increased in steps of up to 100 mg every 7-14 days; maintenance 100-200 mg daily in 1-2 divided doses; increased if necessary up to 500 mg daily, dose titration should be repeated if restarting after interval of more than 5 days.
**Monotherapy of typical absence seizures for lamotrigine**
- **Child 2-11 years** (By mouth): Initially 300 micrograms/kg daily in 1-2 divided doses, for 14 days, then 600 micrograms/kg daily in 1-2 divided doses, for further 14 days, then increased in steps of up to 600 micrograms/kg every 7-14 days; maintenance 1-10 mg/kg daily in 1-2 divided doses, increased if necessary up to 15 mg/kg daily, dose titration should be repeated if restarting after interval of more than 5 days.
**Adjunctive therapy of focal seizures with valproate, Adjunctive therapy of primary and secondary generalised tonic-clonic seizures with valproate, Adjunctive therapy of seizures associated with Lennox-Gastaut syndrome with valproate for lamotrigine**
- **Child 2-11 years (body-weight up to 13 kg)** (By mouth): Initially 2 mg once daily on alternate days for first 14 days, then 300 micrograms/kg once daily for further 14 days, then increased in steps of up to 300 micrograms/kg every 7-14 days; maintenance 1-5 mg/kg daily in 1-2 divided doses, dose titration should be repeated if restarting after interval of more than 5 days; maximum 200 mg per day.
- **Child 2-11 years (body-weight 13 kg and above)** (By mouth): Initially 150 micrograms/kg once daily for 14 days, then 300 micrograms/kg once daily for further 14 days, then increased in steps of up to 300 micrograms/kg every 7-14 days; maintenance 1-5 mg/kg daily in 1-2 divided doses, dose titration should be repeated if restarting after interval of more than 5 days; maximum 200 mg per day.
- **Child 12-17 years** (By mouth): Initially 25 mg once daily on alternate days for 14 days, then 25 mg once daily for further 14 days, then increased in steps of up to 50 mg every 7-14 days; maintenance 100-200 mg daily in 1-2 divided doses, dose titration should be repeated if restarting after interval of more than 5 days.
**Adjunctive therapy of focal seizures (with enzyme inducing drugs) without valproate, Adjunctive therapy of primary and secondary generalised tonic-clonic seizures (with enzyme inducing drugs) without valproate, Adjunctive therapy of seizures associated with Lennox-Gastaut syndromes (with enzyme inducing drugs) without valproate for lamotrigine**
- **Child 2-11 years** (By mouth): Initially 300 micrograms/kg twice daily for 14 days, then 600 micrograms/kg twice daily for further 14 days, then increased in steps of up to 1.2 mg/kg every 7-14 days; maintenance 5-15 mg/kg daily in 1-2 divided doses, dose titration should be repeated if restarting after interval of more than 5 days; maximum 400 mg per day.
- **Child 12-17 years** (By mouth): Initially 50 mg once daily for 14 days, then 50 mg twice daily for further 14 days, then increased in steps of up to 100 mg every 7-14 days; maintenance 200-400 mg daily in 2 divided doses, increased if necessary up to 700 mg daily, dose titration should be repeated if restarting after interval of more than 5 days.
**Adjunctive therapy of focal seizures (without enzyme inducing drugs) without valproate, Adjunctive therapy of primary and secondary generalised tonic-clonic seizures (without enzyme inducing drugs) without valproate, Adjunctive therapy of seizures associated with Lennox-Gastaut syndromes (without enzyme inducing drugs) without valproate for lamotrigine**
- **Child 2-11 years** (By mouth): Initially 300 micrograms/kg daily in 1-2 divided doses for 14 days, then 600 micrograms/kg daily in 1-2 divided doses for further 14 days, then increased in steps of up to 600 micrograms/kg every 7-14 days; maintenance 1-10 mg/kg daily in 1-2 divided doses, dose titration should be repeated if restarting after interval of more than 5 days; maximum 200 mg per day.
- **Child 12-17 years** (By mouth): Initially 25 mg once daily for 14 days, then increased to 50 mg once daily for further 14 days, then increased in steps of up to 100 mg every 7-14 days; maintenance 100-200 mg daily in 1-2 divided doses, dose titration should be repeated if restarting after interval of more than 5 days.
Cautions
Brugada syndrome; Parkinson's disease (may be exacerbated) (in adults); seizures (may be exacerbated) Cautions, further information Seizure exacerbation Lamotrigine may exacerbate seizures in patients with myoclonic seizures (including juvenile myoclonic epilepsy), Dravet syndrome, and Lennox-Gastaut syndrome. A
Side effects
Common or very common Aggression; agitation; arthralgia; diarrhoea; dizziness; drowsiness; dry mouth; fatigue; headache; irritability; nausea; pain; rash; sleep disorders; tremor; vomiting Uncommon Alopecia; movement disorders; vision disorders Rare or very rare Confusion; conjunctivitis; disseminated intravascular coagulation; face oedema; fever; haemophagocytic lymphohistiocytosis; hallucination; hepatic disorders; lupus-like syndrome; lymphadenopathy; meningitis aseptic; multi organ failure; nystagmus; seizure; severe cutaneous adverse reactions (SCARs); tic Frequency not known Suicidal behaviours Side-effects, further information Serious skin reactions including Stevens-Johnson syndrome and toxic epidermal necrolysis have developed (especially in children); most rashes occur in the first 8 weeks. Rash is sometimes associated with hypersensitivity syndrome and is more common in patients with history of allergy or rash from other antiepileptic drugs. Consider withdrawal if rash or signs of hypersensitivity syndrome develop. Factors associated with increased risk of serious skin reactions include concomitant use of valproate, initial lamotrigine dosing higher than recommended, and more rapid dose escalation than recommended.
Interactions
**Severe interactions:**
- There is no evidence that lamotrigine causes clinically significant induction or inhibition of cytochrome P450 enzymes.
- Lamotrigine may induce its own metabolism but the effect is modest and unlikely to have significant clinical consequences.
- In a study of patients with epilepsy, coadministration of zonisamide (200 to 400 mg/day) with lamotrigine (150 to 500 mg/day) for 35 days had no significant effect on the pharmacokinetics of...
- Multiple oral doses of bupropion had no statistically significant effects on the single dose pharmacokinetics of lamotrigine in 12 subjects and had only a slight increase in the AUC of lamotrigine...
- Multiple oral doses of lamotrigine 400 mg daily had no clinically significant effect on the single dose pharmacokinetics of 2 mg risperidone in 14 healthy adult volunteers.
**Other interactions (50):**
- Uridine 5'-diphospho (UDP) glucuronyl transferases (UGTs) have been identified as the enzymes responsible for metabolism of lamotrigine.
- Drugs that induce or inhibit glucuronidation may, therefore, affect the apparent clearance of lamotrigine.
- Strong or moderate inducers of the cytochrome P450 3A4 (CYP3A4) enzyme, which are also known to induce UGTs, may also enhance the metabolism of lamotrigine.
- Those drugs that have been demonstrated to have a clinically relevant impact on lamotrigine concentration are outlined in Table 6.
- In addition, this table lists those drugs which have been shown to have little or no effect on the concentration of lamotrigine.
- However, consideration should be given to patients whose epilepsy is especially sensitive to fluctuations in concentrations of lamotrigine.
Pregnancy
Important safety information For lamotrigine MHRA/CHM advice: Antiepileptics: risk of suicidal thoughts and behaviour (August 2008) See Epilepsy . MHRA/CHM advice: Antiepileptic drugs: updated advice on switching between different manufacturers' products (November 2017) See Epilepsy and see also Prescribing and dispensing information . MHRA/CHM advice: Antiepileptic drugs in pregnancy: updated advice following comprehensive safety review (January 2021) See Epilepsy .
Breast feeding
Present in milk, but limited data suggest no harmful effect on infant.
Hepatic impairment
Manufacturer advises caution in moderate to severe impairment. Dose adjustments Manufacturer advises dose reduction of approx. 50% in moderate impairment, and approx. 75% in severe impairment; adjust according to response.
Renal impairment
Caution in renal failure; metabolite may accumulate. M Dose adjustments Consider reducing maintenance dose in significant impairment. M
Medicinal forms
Solution,Tablet,Tablet,Suspension
Clinical governance
**Author:** MedNext Clinical Team. **Clinical reviewer:** Dr Shameer Deen, MBBS, MS, MRCS. **Sources:** BNF, Indian Pharmacopoeia, CIMS India. **Correction:** Report errors at support@mednext.academy.
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