Permethrin

Permethrin is a topical scabicide and pediculicide (synthetic pyrethroid) medicine available in Bangladesh under many brand names. Below are its uses, dosage, side effects and precautions — and all brands with their current prices.

Permethrin is used for:

• Scabies — the 5% cream is the standard treatment for the mite infestation that causes severe itching (typically worse at night), thread-like burrows and small bumps between the fingers, on wrists, elbows, armpits, waist, buttocks and genitals
• Treatment of household and close contacts of a scabies patient — usually everyone is treated at the same time, even without symptoms
• Head lice — using the preparations and strengths intended for that purpose, as advised by a doctor or pharmacist

A doctor may also use it as part of the plan for crusted (severe) scabies along with other treatment. Diagnosis matters — itching has many causes, so let a doctor confirm scabies first.

For scabies, use Permethrin exactly as your doctor advises. The cream must cover the whole body from the neck down — not just the itchy spots.

1. Bathe or wash with cool water and dry the skin completely; apply to cool, dry skin
2. Apply to every part of the body below the neck — including skin folds, between the fingers and toes, under the nails, wrists, armpits, waist, groin, buttocks and soles. In infants, the elderly and as the doctor directs, the scalp, face (avoiding eyes and mouth) and ears are also treated
3. Leave the cream on for 8–14 hours, usually overnight, then wash off thoroughly
4. If you wash your hands during this period, re-apply cream to them

A second application after 7 days is commonly advised. Treat all household members and close contacts on the same day. Children should be treated under a doctor's guidance.

Side effects of Permethrin are usually mild and limited to the skin:

• Temporary burning or stinging after application
• Tingling or numb feeling
• Itching and mild redness
• Dry skin or mild rash

Important: itching often continues for 2–4 weeks after successful treatment. This is the body's allergic reaction to dead mites and their debris — it does not mean the treatment failed, and the cream should not be re-applied again and again for this itch alone. Seek medical advice if you see new burrows or new spots appearing, signs of skin infection (pus, crusting, spreading redness), or any severe reaction.

• Treat the whole family and close contacts on the same day, even those without itching — otherwise the infestation passes back and forth
• Wash all clothes, bedsheets, pillow covers and towels used in the previous 2–3 days in hot water and dry them in full sun or iron them; items that cannot be washed can be sealed in a plastic bag for at least 72 hours — the mites die away from human skin
• Avoid the eyes, mouth, nose and other mucous membranes; rinse with plenty of water if contact occurs
• Do not apply to broken, weeping or heavily inflamed skin without medical advice
• Persistent itching after treatment is expected — ask your doctor about antihistamines or soothing creams instead of repeatedly re-applying Permethrin
• Use in infants under 2 months only if a doctor decides

Permethrin is applied to the skin and very little is absorbed, so interactions with tablets and other medicines taken by mouth are unlikely. Points to remember:

• Other skin medicines — do not apply steroid creams, other anti-itch creams or moisturisers at the same time as the treatment layer unless your doctor advises; steroids can mask the rash and make it hard to judge cure
• Repeat antiparasitic treatments — do not combine or repeat scabies treatments (for example adding ivermectin or benzyl benzoate) on your own; sequencing is the doctor's decision

Tell your doctor about all medicines and skin products you or your children use before starting Permethrin.

Do not use Permethrin if you:

• Are allergic to permethrin, other pyrethroids or pyrethrins, or any ingredient of the cream
• Are known to be allergic to chrysanthemum-family plants, from which related compounds are derived

It is generally not used in infants under 2 months of age unless a doctor specifically decides. Do not apply it to the eyes or inside the mouth or nose, or to severely broken skin without medical advice. If a previous application caused a severe reaction such as widespread rash, swelling or breathing difficulty, do not use Permethrin again and inform your doctor.

Pregnancy: Permethrin is poorly absorbed through the skin and is broken down quickly in the body. When scabies needs treatment in pregnancy, permethrin cream is generally regarded as the preferred option — but it should still be used only after consulting your doctor, who will confirm the diagnosis and the correct way to apply it.

Breastfeeding: Levels reaching breast milk after skin application are expected to be very low. If you are breastfeeding, ask your doctor; you may be advised to wash the cream off the nipple area before feeding or to time applications around feeds.

Store Permethrin below 30°C in a cool, dry place, away from direct sunlight, heat and open flame.

• Keep the tube or bottle tightly closed when not in use
• Keep out of the reach and sight of children
• Do not use after the expiry date printed on the pack
• Do not pour leftover cream or lotion into drains or ponds — permethrin is harmful to fish; dispose of it with household waste as the pharmacist advises