Dosing and uses of Nix, Elimite, Acticin (permethrin)
Adult dosage forms and strengths
cream
- 5%
liquid
- 1%
lotion
- 1%
Scabies
Cream: Apply from head to toe, leave on for 8-14 hr, rinse; may reapply in 7 days if live mites reappear
Single application usually curative
Head Lice & Nits (Eggs)
Lotion/cream rinse/liquid: apply to washed hair, leave on 10 min, rinse and comb out nits and eggs; may repeat in 7 days if lice or nits still present
Single application usually curative.
Pediatric dosage forms and strengths
cream
- 5%
liquid
- 1%
lotion
- 1%
Scabies & Head Lice
<2 months
- Safety & efficacy not established
>2 months
- Scabies: Apply cream from head to toe; leave on for 8-14 hr, rinse; may reapply in 7 days if live mites reappear; single application usually curative
- Head Lice & Nits (Eggs): Apply lotion/cream/liquid to washed hair, leave on 10 min, rinse and comb out nits and eggs; may repeat in 7 days if lice or nits still present; single application usually curative
Nix, Elimite, Acticin (permethrin) adverse (side) effects
1-10%
Mild and transient burning and stinging (10%)
Pruritus (7%)
Warnings
Contraindications
Hypersensitivity
< 2 months of age (OTC)
Cautions
May exacerbates itching, swelling, and redness temporarily
For external use only
Avoid contact with eyes
May cause difficulty breathing or asthmatic attack in patients with ragweed allergies
Pregnancy and lactation
Pregnancy category: B
Lactation: Not known if distributed in breast milk; may temporarily withhold the drug while the mother is nursing
Pregnancy categories
A: Generally acceptable. Controlled studies in pregnant women show no evidence of fetal risk.
B: May be acceptable. Either animal studies show no risk but human studies not available or animal studies showed minor risks and human studies done and showed no risk.
C: Use with caution if benefits outweigh risks. Animal studies show risk and human studies not available or neither animal nor human studies done.
D: Use in LIFE-THREATENING emergencies when no safer drug available. Positive evidence of human fetal risk.
X: Do not use in pregnancy. Risks involved outweigh potential benefits. Safer alternatives exist.
NA: Information not available.
Pharmacology of Nix, Elimite, Acticin (permethrin)
Mechanism of action
Like natural pyrethrins, permethrin acts as a neurotoxin by depolarizing nerve cell membranes of parasites
The drug disrupts sodium ion influx through cell membrane channels by which membrane repolarization is regulated
Delayed repolarization results in paralysis of nerves in the exoskeletal respiratory muscles of parasite leading to death
Pharmacokinetics
Absorbed: Small amounts (< 2%)
Metabolism: Rapidly metabolized by ester hydrolysis to inactive metabolites
Excretion: Urine
