Phenytek

Adult Dosing .

Dosage forms:  ER CAP: 200 mg, 300 mg

Special Note

[formulation clarification]

Info: phenytoin ER caps contain 8% less drug than chewable tabs and susp; monitor closely and consider dose adjustment if switching between products

seizure disorder

[300-400 mg/day PO divided bid-tid]

Start: 100 mg PO tid; Max: 600 mg/day for maint. tx; Alt: 4-7 mg/kg/day PO divided bid-tid; Info: may consider load of 15-20 mg/kg PO divided in 3 doses given 2h apart, then start maint. dose after 12-24h; consider low start dose in elderly pts and CYP2C9 intermediate or poor metabolizers; dose adjustment may be needed during pregnancy and/or postpartum; adjust dose no more frequently than q7-10 days based on tx response and serum levels; if divided doses unequal, give larger dose qhs; if stable on bid-tid ER dosing, then may switch to qd ER dosing; 100 mg cap not avail. for this brand, see other phenytoin ER products; do not open cap; taper dose gradually to D/C

renal dosing

[see below]

renal impairment: no adjustment; Info: do not give oral loading regimen

HD/PD: no adjustment; no supplement; Info: do not give oral loading regimen

hepatic dosing

[see below]

hepatic impairment: not defined; Info: do not give oral loading regimen

Peds Dosing .

Dosage forms:  ER CAP: 200 mg, 300 mg

Special Note

[formulation clarification]

Info: phenytoin ER caps contain 8% less drug than chewable tabs and susp; monitor closely and consider dose adjustment if switching between products

seizure disorder

[7-9 yo]

Dose: 7-8 mg/kg/day PO divided bid-tid; Start: 5 mg/kg/day PO divided bid-tid; Max: 300 mg/day for maint. tx; Info: may consider load of 15-20 mg/kg PO divided in 3 doses given 2h apart, then start maint. dose after 12-24h; consider low start dose in CYP2C9 intermediate or poor metabolizers; adjust dose no more frequently than q7-10 days based on tx response and serum levels; if divided doses unequal, give larger dose qhs; if stable on bid-tid ER dosing, then may switch to qd ER dosing; 100 mg cap not avail. for this brand, see other phenytoin ER products; do not open cap; taper dose gradually to D/C

[10-16 yo]

Dose: 6-7 mg/kg/day PO divided bid-tid; Start: 5 mg/kg/day PO divided bid-tid; Max: 300 mg/day for maint. tx; Info: may consider load of 15-20 mg/kg PO divided in 3 doses given 2h apart, then start maint. dose after 12- 24h; consider low start dose in CYP2C9 intermediate or poor metabolizers; adjust dose no more frequently than q7-10 days based on tx response and serum levels; if divided doses unequal, give larger dose qhs; if stable on bid-tid ER dosing, then may switch to qd ER dosing; 100 mg cap not avail. for this brand, see other phenytoin ER products; do not open cap; taper dose gradually to D/C

[>16 yo]

see Adult Dosing

renal dosing

[see below]

renal impairment: no adjustment; Info: do not give oral loading regimen

HD/PD: no adjustment; no supplement; Info: do not give oral loading regimen

hepatic dosing

[see below]

hepatic impairment: not defined; Info: do not give oral loading regimen