Chlorphenamine

What is Chlorphenamine?

Chlorphenamine is an antihistamine that treats allergy symptoms like itching, watery eyes and sneezing. Unlike more common antihistamines, Chlrophenamine often causes drowsiness, which can help you sleep better if scabies are causing nighttime itching. The medical term for this is nocturnal pruritus.

Scabies is a skin condition caused by mites that burrow into your skin. These mites, called Sarcoptes scabiei, lay eggs in the epidermis (the outermost layer of skin) that hatch after 3 or 4 days. Once hatched, the larvae (baby mites) live in your skin, causing intense itchiness and a rash on any areas where the mites are present.^[1]

Left untreated, scabies can last for months and sometimes lead to more serious conditions. Although antihistamines like Chlorphenamine don’t treat your scabies directly, they might help with itchiness and reduce your urge to scratch.

How does Chlorphenamine work?

Antihistamines are so-called because they block histamine, a compound in your body that protects from foreign invaders, such as parasites.^[2]When you have an allergy, your immune system tells your body that the allergen is a threat, and produces histamine as a response. Excessive histamine, however, is produced as a reaction to ‘harmless’ triggers, like dust and pollen. Your body reacts in different ways, such as making your nose run, or tightening your breathing by constricting muscles. Because these excessive immune responses can be harmful, antihistamines are used to calm these symptoms down.

Chlorphenamine is a strong antihistamine that causes drowsiness. If your itchiness from scabies is made worse by hives, or your skin is itchy because of other allergies, Chlrophenamine can relieve these symptoms by counteracting the effects of histamine.

What doses of Chlorphenamine are there?

Chlorphenamine is available as 4mg tablets. The usual dose is one tablet every 4-6 hours.

You can take a maximum of 6 tablets a day, but it might not be necessary to take any more than one tablet a day. To help with nocturnal itching caused by scabies, you might be advised to take Chlorphenamine in the evening, before bed. The sedative effect can help you fall asleep while easing the itchiness.

How to take Chlorphenamine

Chlorphenamine tablets should be swallowed whole with water.

Because the medication causes drowsiness, it’s best to take it in the evening. If you’re taking it in the day, try to limit activities where you need to be alert. You should avoid driving or operating any machinery after you’ve taken your tablet.

How long does Chlorphenamine take to work?

Chlorphenamine starts to work anywhere between 30-60 minutes after taking it.^[1]
If the itching from scabies is keeping you up at night, you might be advised to take a tablet just before bed. As well as helping you drift off, Chlorphenamine can prevent your scabies itch from waking you up during the night.

What should I do if I make a mistake while using Chlorphenamine?

Taking too much Chlorphenamine can put you at risk of having convulsions, so you should always stick to the amount a clinician has advised you to take.

If you think you’ve taken too many tablets, go to the casualty department at your nearest hospital for help as soon as possible. As Chlorphenamine causes drowsiness, you should also avoid driving.

There’s never any need to take a double dose of Chlorphenamine to make up for a tablet you’ve missed. Simply skip the missed dose and carry on as normal.