2. Introduction
ā¢Drugs used to kill parasites that live on body
surface
ā¢ Lice ā Pediculosis sp. ā wingless insects
ā¢Mites ā Sarcoptes/Acarus scabiei ā
Arachnids ā minute arthropods infesting
human hair and skin
3. Scabies
ā¢ Highly contagious mite
ā¢Burrows through the epidermis, laying eggs ā
form papules ā immenseitching
ā¢ Secondary infection ā antibiotics
ā¢ Finger webs
ā¢ Forearm, trunks, genitals and lower legs
ā¢ Family members
ā¢ Cross infection andre-infection
5. Pediculosis
ā¢The lice thrive on head - P. capitis
ā¢ Body ā P. corporis
ā¢ Pubic region ā P. pubis
ā¢Cause itching, suck blood and produce typhus and
relapsing fever
ā¢The eggs are called nits ā attached to hair and
clothes by chitin like content
8. Sulfur ointment
ā¢ Oldest scabicide ā weak pediculocide, antiseptic, fungicide an
keratolytic
ā¢ MOA: Slowly reduced to H2S and SO2on skin and pentathionic acid
ā¢ pentathionic acid ā dissolve the cuticle of mice and kill it
ā¢ Reactions are carried out by epidermal cells and arthropod
themselves
ā¢ Used as 10% ointment ā After a warm scrubbing bath (to open up
burrows) ā messaged over the entire body (below neck) ā 3
consecutive nights ā soap water bath on 4th day
ā¢ Disadvantages:
ā¢Messy treatment
ā¢Socially unacceptable ā interfere with person`s vocation
ā¢Repeated applicationneeded
9. Permethrin
ā¢ Broad spectrum
ā¢ Most efficacious and most convenient for both scabies and lice
ā¢ MOA: Neurological paralysis of insects ā delayed
depolarization
ā¢ Toxicity lower in human than lindane
ā¢ Persists over skin for days but systemic absorption low
ā¢ 100% cure rate and resistance rare
ā¢ Effective in lindane non-responsivecases
ā¢ ADRs: Transient burning, itching, tingling, erythema and rash
ā¢ Preparations: For scabies ā 5% cream, 1$ soap and 5% lotion
For head lice: 1% lotion and 5% cream
ā¢ First choice drug now for scabies and lice
11. Lindane
ā¢Gamma benzene hexachloride
ā¢ broad spectrum ā lice and mites
ā¢MOA: Penetrates to insects through their chitinous cover and
affects nervous system
ā¢ Head lice ā 67% to 92%cure rate and scabies ā 84 t0 92%
ā¢ Lower efficacy than permethrin andresistance
ā¢ Combines with Benzyl benzoate ā100%
ā¢ Preparations: 1% lotion and cream
ā¢Pediculosis: apply over scalp, 12 ā 24 hours, shower cap ā repeat
after one week if needed, avoideyes
ā¢For Scabies: Rubbed over body below neck and scrub bath after
12 -24 hours ā repeat after one week if needed
ā¢Disadvantages: Lipid soluble, gets absorbed, systemic toxicity ā
CN stimulation, vertigo, convulsion (Children) and cardiac
arrhythmia
12. Lindane
ā¢Widely distributed in the body ā fats
ā¢Metabolized and eliminated and half-life 24
hours
ā¢ Microsomal enzyme inducer
ā¢ Less favoured for treatment of scabies
ā¢ Whole body application ā systemic toxicity
ā¢Avoid in infants, young children and
pregnancy
Source: Google Images
13. Benzyl benzoate
ā¢ Oily liquid with faint aromatic smell
ā¢ The emulsion is applied all over the body and 2nd
coat on next day ā except face and neck
ā¢ Wash off after 24 hours
ā¢ Convenient and does not interfere normal works
ā¢70 ā 100% cure rate in scabies ā no systemic
toxicity
ā¢ Contraindicated in children - Neurological symptoms
ā¢ Preparatin ā 25% lotion
14. Other drugs
Crotamiton
ā¢ Scabicidal, pediculocide and antipruritic
ā¢ Low cure rate
ā¢ Lesser systemictoxicity
ā¢ Preferred in children
ā¢10% cream andlotion
Dicophane (DDT)
ā¢ Popular insecticide fpor mosquitoes, flies and pests
ā¢ Scabies and pediculosis 1 ā 2% lotion or cresam
ā¢ Washed off after 24 hours
ā¢Absorbed through skin and ā enzyme induction, rashes, tremor
etc.
ā¢ Acts as neurotoxin forarthropods
15. Ivermectin
ā¢ Source: Streptomyces avermitilis
ā¢Anthelmintic drug ā also useful in scabies
and pediculosis
ā¢ SARS Cov 2 ???
ā¢Only orally effective drug ā 12 mg single
dose ā 100% cure rate
ā¢ AIDS with scabies and head lice also
ā¢ Replaced DEC ā in River blindness
ā¢ DOC in Strongyloidosis
ā¢ Bancroftian and brugian filaria
Source: Google Images
16. Ivermectin ā contd.
MOA:
ā¢Nematodes develop tonic paralysis
ā¢ Acts through special type of Cl- channel present
only in invertebrates
ā¢No such channel in flukes and tapeworm ā
ineffective
ā¢ Potentiation of GABAergic receptors
ā¢ p-glycoprotein related efflux from brain in human ā
no action