This article has been medically approved by Superintendent Pharmacist Shilpa Shailen Karia, MRPharmS. - GPhC Reg No: 2087328
Antihistamines are medicines that are mainly used to relieve the symptoms of allergies. Read our article below for more information on different antihistamines.
Hydroxyzine may be used to treat hives or contact dermatitis. It can be used as a sedative to treat anxiety and depression as it reduces activity in the central nervous system. It is also given with other medications during and after general anaesthesia. 
Promethazine is used for short-term insomnia, hay fever, hives, morning sickness, travel sickness, vertigo, and coughs and colds. Promethazine is often sold as Avomine, Phenergan, or Sominex. It is also sometimes mixed with paracetamol, dextromethorphan, pholcodine, or pseudoephedrine to treat coughs and colds or pain. Popular brand names are: Day & Night Nurse and Night Nurse. 
Fexofenadine is used for hay fever, conjunctivitis, eczema, hives, reactions to insect bites and stings, some food allergies. 
Loratadine is used for hay fever, conjunctivitis, eczema, hives, reactions to insect bites and stings, and some food allergies. Popular brand names are: Clarityn.
Which is better?
There isn’t much evidence that there is a ‘better’ antihistamine. Some people may find one type works better for them, so you might need to try several types to find the one that works for you. Less drowsy antihistamines are generally the best option to manage your symptoms. However, if your symptoms are interrupting your sleep, you may choose a drowsy antihistamine for at night.