Loratadine

What it is

Loratadine is a second-generation antihistamine that blocks peripheral H1 receptors, so histamine released in an allergic reaction can no longer drive itching, sneezing, nasal discharge and hives. It penetrates the brain poorly, which is why it is regarded as a non-sedating antihistamine. It is used for allergic rhinitis and skin allergy such as urticaria.

Used for

• Allergy

What to know while taking it

Food does not meaningfully change how well it works, so it can be taken with a meal or on an empty stomach, whichever is easier to remember. It is metabolised in the liver, so liver disease or drugs that strongly affect liver enzymes can raise the amount circulating in the body. Although it is described as non-sedating, some people still notice drowsiness, and alcohol or sedatives can make that more likely. Its effect is on symptoms only; it does nothing about the exposure that caused them.

When to see a doctor

Symptoms that continue or worsen despite regular use are worth a medical opinion rather than adding a second antihistamine. Facial or throat swelling, widespread hives, or any difficulty breathing calls for urgent care, not a further tablet.