Read the leaflet that comes with your particular brand for further information. All antihistamines work pretty well to reduce symptoms of allergy. Your doctor or pharmacist may advise or prescribe a particular antihistamine depending on the cause of your allergy and on whether you require a sedating or non-sedating medicine. For other conditions, specific antihistamines may be used.
For example, cyclizine and promethazine teoclate are used for feeling sick nausea and being sick vomiting , not for hay fever. Chlorphenamine is the antihistamine most used in an emergency situation such as anaphylaxis, and may be given by injection in this situation.
An antihistamine tablet typically starts to work within 30 minutes after being taken. The peak of effectiveness is typically within hours after being taken. This can vary depending on the reason for treating you. If you have hay fever you may take the medicine throughout the pollen season. Most people who take antihistamines do not have any serious side-effects.
If side-effects do occur, they are usually minor. The most common are:. For a full list of all the side-effects and possible interactions associated with your medicine, consult the leaflet that comes with your medication.
If you think you have had a side-effect to one of your medicines you can report this on the Yellow Card Scheme. You can do this online at www. The Yellow Card Scheme is used to make pharmacists, doctors and nurses aware of any new side-effects that medicines or any other healthcare products may have caused. If you wish to report a side-effect, you will need to provide basic information about:. Most people can take antihistamines safely. Antihistamines should not be used by people with a rare metabolic disorder called acute porphyria.
In addition, they may not be suitable for people with liver or kidney problems. First-generation antihistamines may not be suitable for men with prostate enlargement benign prostatic hyperplasia. They may also not be suitable for people with raised pressure in the eye acute glaucoma or who are at risk of glaucoma. Women who are pregnant or breast-feeding are usually advised not to take antihistamines. This is because it is not known if they do any harm and studies cannot be done on women in this situation just in case.
However, they are not known to cause harm. If certain conditions such as hay fever or morning sickness make you very unwell in pregnancy, the benefit of treatment may be more than the very small risk of any harm. Your doctor would talk this over with you and prescribe one of the antihistamines believed to be safe in pregnancy if you choose to take one.
Similarly, in breast-feeding women, in some cases the benefits may be more than the risk. Antihistamines do come through in small quantities into breast milk, although they are not known to cause any harm. A full list of people who should not take antihistamines is included with the information leaflet that comes in the medicine packet.
If you are prescribed or buy an antihistamine, read this to be sure you are safe to take it. Usually it is possible to find an antihistamine which keeps your symptoms controlled. Sometimes you may need to experiment and try more than one to find the one that works best for you. Antihistamines are generally more effective when taken constantly rather than intermittently. This is particularly applicable for people with hay fever seasonal allergic rhinitis.
In the summer months the pollen count is generally higher and you may be in contact with the allergen on a regular basis. Taking the medication regularly may help keep your symptoms under control. Their effectiveness will also depend on the dose you take and what form the medicine is given in. Drug companies are naturally pretty reluctant to go around testing medicines on pregnant or breast-feeding women, so there aren't any studies to guide them.
They tend to advise against to be on the safe side, although there is no evidence they cause a problem. Discuss this with your doctor who will talk you through the options. If the benefits of treatment are thought to outweigh any possible risks, the one usually advised is loratadine. Alcohol interacts with antihistamines. Probably the effect is greater for the sedative antihistamines, but it can occur with either type.
Alcohol and an antihistamine in combination are more likely to make you feel sleepy than either on its own. So the answer is be wary and don't overdo it! Speak to a pharmacist or GP before taking antihistamines if you're already taking other medicines. There may be a risk the medicines do not mix, which could stop either from working properly or increase the risk of side effects.
Examples of medicines that could cause problems if taken with antihistamines include some types of:. Try not to drink alcohol while taking an antihistamine, particularly if it's a type that makes you drowsy, as it can increase the chances of it making you feel sleepy.
Food and other drinks do not affect most antihistamines, but check the leaflet that comes with your medicine to make sure. Some antihistamines may not be suitable in these cases. A pharmacist or doctor can recommend one that's best for you. Always read the leaflet that comes with your medicine to check it's safe for you before taking it or giving it to your child.
Antihistamines block the effects of a substance called histamine in your body. Histamine is normally released when your body detects something harmful, such as an infection. It causes blood vessels to expand and the skin to swell, which helps protect the body.
But in people with allergies, the body mistakes something harmless — such as pollen, animal hair or house dust — for a threat and produces histamine. The histamine causes an allergic reaction with unpleasant symptoms including itchy, watering eyes, a running or blocked nose, sneezing and skin rashes. Antihistamines help stop this happening if you take them before you come into contact with the substance you're allergic to. Or they can reduce the severity of symptoms if you take them afterwards.
The leaflet that comes in the packet with your medicine will have detailed information about it, including how to take it and what side effects you might get.
Decongestants work by narrowing the blood vessels in your nose, which reduces the blood flow into the nose, thus reducing swelling. Decongestants are usually only used after antihistamines and corticosteroid nasal sprays have failed to relieve symptoms of a congested nose.
Decongestants should not be given to children younger than 6 years — always check the instructions to see if the product is suitable before giving to a child.
Topical decongestants , such as oxymetazoline, xylometazoline and tramazoline, which come in a nasal spray, can help relieve nasal congestion. However, they should not be used for longer than 3 days, as rebound congestion can occur through extended use. Oral decongestants such as pseudoephedrine are also only recommended for short-term use.
These tablets also relieve symptoms of nasal congestion, but may cause restlessness, anxiety and insomnia, particularly in children. People with high blood pressure, heart problems, hyperthyroidism, glaucoma, urinary retention, diabetes and those taking MAOI antidepressants, should avoid oral decongestants. Saline sodium chloride nasal sprays e. Fess or saline irrigation can help with some hay fever symptoms and help remove pollen and other allergens from the lining of the nose.
Saline nasal sprays are available from the pharmacy. They can be used in conjunction with any other treatment for hay fever symptoms and may help keep the nasal lining clear of mucus that may block your other medications from reaching where they need to be. Combination products are available as tablets that include an antihistamine in conjunction with a decongestant such as pseudoephedrine.
These products are available in the pharmacy, but are kept behind the counter and need the pharmacist to dispense them. They may be used when a person needs the symptomatic relief of an antihistamine, in combination with a decongestant to relieve congestion in the nose.
Products containing pseudoephedrine may cause insomnia, restlessness, anxiety and other effects mentioned above. They are not suitable for people with high blood pressure and some other conditions. Another oral medication that can be used to treat seasonal allergic rhinitis symptoms is montelukast e. This medicine — a so-called leukotriene receptor antagonist — can also be used in the treatment of asthma.
This is a prescription medicine. There is no evidence for supplements such as bee pollen extract, propolis and echinacea, which are sometimes promoted as helping with hay fever symptoms. In fact, they have been linked with anaphylaxis — a serious life-threatening allergic reaction in some cases. If you are not getting relief from your symptoms after a month of treatment, your doctor may suggest you see an allergy specialist or clinical immunologist.
The specialist will take a medical history and may do skin prick tests and blood tests to help with diagnosis and treatment of your allergies. Immunotherapy is also known as desensitisation and can achieve lasting relief from hay fever symptoms in many people. Immunotherapy involves giving a person increasing amounts of the allergen to which they are allergic, e.
Immunotherapy works best for people who have a strong positive in one allergen on skin prick testing. It is not usually used for those with multiple allergic triggers.
Immunotherapy has to continue for up to years, so a person has to be committed to make it work. Immunotherapy is carried out by allergy specialists in Australia. MedLine Plus. Antihistamines for allergies. Rhinitis updated Feb Is it allergic rhinitis hay fever?. Updated July NPS Medicinewise. Nasal decongestants. Aug Australian Doctor. Management of allergic rhinitis. March Top 3 tips to beat hay fever. Sept Allergic conjunctivitis. Skip to content. Minimising exposure to allergens It may sound obvious, but knowing which allergens trigger your symptoms can go a long way to helping you manage your hay fever.
Author: myDr. White-tail spider bite — symptoms and treatment Allergy September 27, ,.
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