Antihistamines are used in the treatment of allergic responses, particularly nasal allergies, for example hay fever, and can reduce vasomotor rhinitis. They are all able to reduce rhinorrhoea and sneezing but are less able to reduce nasal congestion.
Broadly speaking they may be divided into two groups - sedative and non-sedative, the distinction being the amount the drug crosses the blood-brain barrier and thus the amount of effect the drug has centrally. The non- sedative antihistamines are a more recent development, and it should be noted that they can have a sedative effect in some people.
Last reviewed 01/2018