How Do Antihistamines Work?

Antihistamines lessen or eliminate the allergic response caused by a wide variety of allergic responses. They are classified as a class of drugs known for treating allergic reactions and their related symptoms.

Histamine is the chemical messenger that the body’s immune system releases during an allergic reaction, and antihistamine medications function by preventing its effects.

However despite the widespread use and results overall, antihistamines don’t deal with the underlying cause of allergies.

Antihistamines merely mask or conceal the symptoms, which may reappear once the drug wears off.

As a result of this many people frequently use this type of drug to control their reactions, in fact almost 1 in 5 in Australia suffers from an allergic condition and without the proper management this can affect your daily activities and life.

Let’s Explore :

• How antihistamine medications work
• How to utilise the drug effectively
• The side effects of antihistamines
• When to seek a doctor’s help

At Allergy Testing Sydney our highly experienced and accredited medical professionals understand how to diagnose the root cause of your allergies, and offer accurate testing in our laboratory.

We will test your allergies and irritants so you can effectively manage your symptoms in the long term.

What Are Antihistamines?

Antihistamine medications were created and developed to offset the effects of histamine on the body, and to block the histamine response.

A chemical substance called histamine is essential to the human body’s immune system and response to perceived dangers, such as allergens.

For instance, if your body reacts to dust or certain types of food, histamines are released in the body in reaction to an allergen and it attaches itself to particular cell receptors to cause typical allergy symptoms.

Antihistamines come in two primary varieties :

– First Generation :

These older types of medications include chlorpheniramine and diphenhydramine, for instance (Benadryl) which is a common drug. This type of medicine can pass through the blood brain barrier and can make you feel sleepy. Usually used as a temporary remedy for allergy symptoms.

– Second Generation :

These are newer drugs, such as fexofenadine (Telfast), loratadine (Clarityn) and cetirizine (Zyrtec), are less likely to make you fall asleep since they have a harder type passing the blood brain barrier. Which are often selected for managing allergies over the long term.

What Are Antihistamines Used for?

The main purpose of antihistamine is to treat a range of allergic diseases and symptoms that go along with them. However, the point of antihistamines is to suppress the immediate effects of allergies only rather than giving a long-term solution to the cause.

Some of the most common uses for antihistamines :

• Hay Fever : Which is also known as allergic rhinitis, characterised by symptoms like itchy eyes, runny nose and sneezing, which can be managed with antihistamines, particularly during high pollen seasons.
• Urticaria (hives) : Antihistamine, which lessen inflammation and irritation and is effective treatment for itchy skin and inflammation
• Conjunctivitis : This is an eye or an ocular ailment which causes redness, irritation and watering. You can get relief with antihistamine eye drops or oral medications.
• Food allergies : Can help control severe allergic reactions to food as well as help manage moderate symptoms. It’s important to remember that serious food allergies require immediate medical attention, along with any other conditions that become severe.

While antihistamines may cover up these effects of these common allergies it does not create a future management plan for your allergies.

At our Allergy Testing clinic we have a medical laboratory and testing facilities which can help identifying the root cause of your allergies. We offer specialised treatments and customised assessments by our highly trained medical practitioners.

Getting the right testing is crucial for people who are worried about food allergies. Our specialised food allergy testing in Sydney, medical team can provide you with helpful results to help maintain and regulate your allergies.

How Long Does it Take for Antihistamines to Work?

Usually, most antihistamines start to work from 30 minutes to 2 hours after consumption. Depending on the drug and your biology, antihistamines might have a varied effect on the individual.

You should start to feel the effects, when you notice relief to your allergies. For instance your nose stops dripping or the redness and swelling from a mosquito bite reaction starts to become less red and inflamed.

However in the case of more severe illness like chronic urticaria (hives), it might take a few days of regular use to feel the full effects.

There are some popular brands of antihistamines tablets in Australia like :

• Zyrtec (Cetirizine)
• Claratyne (Loratadine)
• Telfast (Fexofenadine)
• Polaramine (Dexchlorpheniramine)

The following medications and dosage can provide relief between 12-24 hours

Do I Need a Prescription for Antihistamines?

Not always. Many antihistamines can be purchased over the counter in Australia without a prescription.

This includes the majority of second generation antihistamines, such as fexofenadine, cetirizine and loratadine.

In some situations a prescription might be necessary :

• Higher doses : A doctor may recommend a higher does if the usual over the counter dosages prove ineffective
• Particular formulations : A prescription may be necessary for some antihistamine formulations, especially those that are taken with other medications.
• First generation antihistamines : Due to the possibility of adverse effects, some of these older antihistamines might need a prescription
• Children under specific ages : Young children may need a prescription for an antihistamine, depending on the specific medication type.
• Chronic conditions : Your doctor might choose to prescribe and oversee your prescription use if you require long term treatment and will monitor your medication usage.

 

Important Note : Any over the counter medications must be prescribed by a medical professional.

Do antihistamines have any side effects?

Although not everyone experiences them, antihistamines can have adverse effects, just like any other medication.

Depending on whether you’re using first or second generation antihistamines the side effects may differ.

First generation antihistamines can result in :

• Sedation and drowsiness
• Light-headedness
• Dry eyes, nose and mouth
• Visual impairment
• Urinary difficulties

Although second generation antihistamines often have fewer adverse effects they might cause :

• Light sleepiness, less prevalent than in first generation
• Headaches
• Dry mouth
• Nausea

In more rare situations antihistamines may result in more severe effects like :

• An elevated heart rate
• Hallucination or confusion which is common in older adults
• Epilepsy
• Severe allergic responses

You should always carefully read any medication instructions and take it as prescribed.

If you experience any severe side effects you should stop taking the medication immediately and get in touch with your doctor right away.

In emergency situations you can call the ambulance for immediate assistance.

When Should I See a Doctor?

Most antihistamines are safe to use, and most people will use them without side effects, however there are some circumstances in which you should speak to a doctor before taking them.

This can include :

– Underlying medical conditions :

Before using antihistamines, speak with your doctor if you have any chronic illness, especially liver or kidney disease, glaucoma, an enlarged prostate or thyroid issues.

– Pregnancy or breastfeeding :

Before using any drug during pregnancy or breastfeeding always consult your healthcare partitioner.

– Children :

Before giving your child any antihistamines, speak with a paediatrician for advice on administering any medication for very young children.

– Elderly adults :

Should always speak with your doctor because they may be more prone to adverse effects.

– Taking other medications :

You should always consult your doctor about the use of any medications you might currently be taking as antihistamines can interfere with other medication use.

How to Treat Allergies Properly?

At Allergy Testing, our skilled and highly trained medical professionals will evaluate and assess you before any treatment plan is put into place:

–  Firstly, one of our allergy testing professionals will assess your situation, we will ask you about the challenges you face with allergies or if you have any reactions prior to testing

–  Next you may need to undergo an allergy test to identify your specific allergens.

–  We’ll provide a comprehensive breakdown of your results to guide and discuss with you the next course of action and take you through the next steps.

–  A treatment plan will be created based on your specific results and a ongoing solution so you can get the help you need.

To book an allergy test please visit our website on skin prick testing or food allergy testing.

For information on how to get an allergy test in Australia please visit our valuable blog resource online.

Resources :

Some helpful healthcare resources include:

Australian Society of Clinical Immunology and Allergy (ASCIA)

NPS MedicineWise

HealthDirect Australia: Antihistamines 

Therapeutic Goods Administration (TGA)

How Allergy Testing Can Help

Our medical professionals at Allergy Testing Australia, led by Dr Richard Baker are specialists in identifying and treating allergies.

In addition to offering thorough allergy testing, we offer tailored guidance to help you manage your allergies, including the use of antihistamines.

To make an appointment and to find out more about how allergy testing can benefit you contact us today.