Anesthetic product	Methods	Onset/duration	Effectiveness	Complications
TAC (0.5% tetracaine, 1:2,000 epinephrine, and 11.8% cocaine)	2 to 5 mL (1 mL per cm of laceration) applied to wound with cotton or gauze for 10 to 30 minutes	Onset: effective 10 to 30 minutes after application Duration: not established	May be as effective as lidocaine for lacerations on face and scalp	Rare severe toxicity, including seizures and sudden cardiac death
LET (4% lidocaine, 1:2,000 epinephrine, and 0.5% tetracaine)	1 to 3 mL directly applied to wound for 15 to 30 minutes	Onset: 20 to 30 minutes Duration: not established	Similar to TAC for face and scalp lacerations; less effective on extremities	No severe adverse effects reported
EMLA (2.5% lidocaine and 2.5% prilocaine)	Thick layer (1 to 2 g per 10 cm2) applied to intact skin with covering patch of Tegaderm	Onset: must be left on for 1 to 2 hours Duration: 0.5 to 2 hours	Variable, depending on duration of application	Contact dermatitis, Methemoglobinemia (very rare)
Iontophoresis	Small current applied to lidocaine-soaked sponges on intact skin	Onset: 10 minutes Duration: 10 to 20 minutes	Good for small procedures, depth of anesthesia greater than EMLA	Stinging sensation; may burn skin if high current