Posted by ed_uk2010 on May 27, 2013, at 14:05:15
In reply to Re: When will Lamictal kick in? » ed_uk2010, posted by SLS on May 27, 2013, at 6:47:18
Hello,
>I didn't know this. I had thought that for epilepsy, a great many people need to go to 500 mg/day. Thanks for the information.
In epilepsy, most patients who are going to respond well (or remit) on a particular medication do so at fairly moderate doses. Only a minority experience substantial additional benefit by taking very high doses.
For example, the dose of valproate should rarely need to exceed 30mg/kg/day in divided doses, which often amounts to about 2g per day. Carbamazepine is normally effective at up to 800mg per day in divided doses - and doses should rarely exceed 1200mg.
The dose of lamotrigine depends partly on whether it is used alone or with other medications, but is usually between 100mg and 400mg per day. Lamotrigine is potentiated by valproate, both on a pharmacokinetic and pharmacodynamic level. In contrast, lamotrigine levels are reduced by enzyme-inducing drugs such as carbamazepine and phenytoin. Very high doses of lamotrigine eg. 500-700mg/day are occasionally used in refractory epilepsy for patients also taking enzyme-inducing drugs, but adverse effects may be increased, any there may be little additional benefit above 400mg.
Optimal lamotrigine doses for the majority of adults with focal or generalised epilepsy are as follows:
Monotherapy:
100mg to 200mg per day, sometimes up to 300mg per day, rarely more. Around 200mg/day may be chosen as an initial target dose, or the drug may be titrated to effect.Combination therapy with valproate:
Very gradual titration up to 100-200mg per day. Not more than 200mg per day.Combination therapy with an enzyme-inducing drug: 200mg to 400mg per day, always in divided doses.
poster:ed_uk2010
thread:1044255
URL: http://www.dr-bob.org/babble/20130527/msgs/1044354.html