Lamotrigine
Rash
The appearance of a rash occurring between five days and eight weeks of taking lamotrigine may have serious consequences. Some fever or flu-like symptoms may be present before or at the same time as the rash. A rash that occurs in the first five days of taking lamotrigine is probably nondrug related but regardless, the patient should stop taking the drug and contact their doctor or psychiatrist as it may still represent a lamotrigine (hypersensitivity-type) reaction with potential internal organ involvement.
1. The more common, less serious rashes A rash is most likely to be less serious if it has the following characteristics:
fine red spots that do not merge together, are not tender to the touch, but may be itchy
no accompanying fever or flu-like symptoms either before or at the same time as the rash
peaks within days and settles in 10-14 days.
2. The rare but more serious rash potentially with a severe, life-threatening reaction:
is accompanied by fever, flu-like symptoms or lack of appetite
involves the lining membranes of the eyes, lips, mouth, nostrils, genital or anal areas (muqueuses - haut du cou)
is prominent on the neck and upper trunk
merging, widespread red swollen rashes (wheals or hives) sometimes with round red target-like spots
purplish, small spots or larger areas of skin discoloration that, when pressed with the finger, do not go white as other rashes do (sous cuttanée), and are tender to the touch
skin swelling and redness all over the body, with or without widespread shedding of the skin (sometimes in large sheets).
https://www.blackdoginstitute.org.au/wp-content/uploads/2020/04/7-lamotrigine-associated-rash.pdf
Cominaison avec Epival
Reduce the lamotrigine dose by 50% of the general dose when combined with valproate. Start valproate at low dose and increase dose based on serum concentration slowly.
Ex:
Réduire Epival à 250mg PO QHS x 1 semaine puis cesser
Débuter lamotrigine à 12,5mg PO QHS après que l'Épival ait été réduit x 3 jours.
Augmenter lamotrigine à 25mg PO QHS après 1 semaine à 12,5mg. Réévaluation médicale ensuite pour la suite de la prescription. Merci
https://wiki.psychiatrienet.nl/wiki/Combining-Lamotrigine-Valproic_acid