First and second-generation antihistamines – Know what may work best for you.

Allergic diseases are increasing in both first world as well as lower and middle-income countries. A third of South Africans will suffer from some allergic disease during their life1. The most common allergies result in eczema, asthma, allergic rhinitis (hay fever), urticaria (hives), food allergy and anaphylaxis1.

Some allergies are seasonal, particularly widespread in spring and summer, when reactions to allergens such as tree pollen are prominant2. Whilst other allergies are perennial, or all year round, and include allergies to things such as dust, mould, cockroaches, feathers, and pet dander2.

Seasonal allergic rhinitis (AR), also known as hay fever, is associated with specific seasons of the year, typically in spring3.

With allergy season upon us, people may be looking for over the counter products to assist in the relief of their allergy symptom but may not be aware of which treatments are best. Pharmacists will also be making recommendations based on the individual patients’ needs3.

Dr Corli Lodder of the Allergy Clinic in Boksburg, Johannesburg, says that educating consumers about antihistamines is very important, especially around the difference in first and second generation antihistamines4.

Antihistamines are usually the first medication to try for the relief of allergy symptoms5. When your body encounters an allergy trigger, such as pollen for example, it produces chemicals called histamines, this is an inflammation response. These histamines cause the tissue in your nose to swell (making it stuffy), your nose and eyes to run, and your eyes, nose, and sometimes your mouth to itch. Sometimes you may also get an itchy rash on your skin, called hives5.

Antihistamines reduce or block histamines, which is how they can reduce or stop allergy symptoms5. Furthermore, histamine and a substance called platelet-activating factor (PAF) both play an important role in allergies such as allergic rhinitis6.

Antihistamines can be classified as first and second generation and both can alleviate AR symptoms or other upper respiratory allergies3.

“First generation bind non-specifically to the histamine receptors and can cause side-effects including drowsiness and cognitive impairment. It also causes poor quality of sleep, even though it can make you drowsy and sleepy, the REM-sleep cycle will be impaired, and fatigue can follow,” explains Dr Lodder who adds that sometimes first-generation antihistamines used in combination with flu and cough medicine as well as in allergies can lead to overdosing and even more side-effects4.

Dr Lodder says that lack of concentration at school and work due to cognitive impairment may also be a side effect of some first-generation antihistamines. “In children, the concentration at school can be impaired leading to overdiagnosis of Attention Deficit Disorder 4” she says. 40% of allergy sufferers are children1.

Because some second-generation antihistamines are less likely to cross the blood-brain barrier than first-generation antihistamines, they are associated with fewer nervous system effects, such as drowsiness3. “Second generation antihistamines are more specific in the binding of the receptor and are safe to use daily4” Dr Lodder says.

It is for this reason that second-generation antihistamines are sometimes also referred to as “non-sedating” antihistamines3. Some second-generation antihistamines are also appropriate for use in children3.

A second-generation antihistamine, from iNova Pharmaceuticals, is the first to have an effect on both histamine and platelet-activating factor (PAF) 6. It is a non-sedating, long-acting antihistamine7.

Allergies such as allergic rhinitis are very common conditions and symptoms can cause significant disruptions in daily activities. There are many effective treatments available for these allergies, but patients may be confused and overwhelmed by product labelling and options3. Speak to your doctor or pharmacist about a suitable option for you or your allergy as well as your specific symptom relief needs.

DISCLAIMER: This editorial has been commissioned and brought to you by iNova Pharmaceuticals. This editorial has content that includes independent comments and opinions from independent healthcare providers and are the opinions and experiences of that particular healthcare provider which are not necessarily that of iNova Pharmaceuticals. Content in this editorial is for general information only and is not intended to provide medical or other professional advice. For more information on your medical condition and treatment options, speak to your healthcare professional.

Name and business address of applicant: iNova Pharmaceuticals (Pty) Limited. Co. Reg. No.1952/001640/07, 15E Riley Road, Bedfordview. Tel. No. 011 087 0000. IN3036/18


  1. Allergies – Allergy Foundation South Africa ( [cited November 2022]
  2. What’s the difference between seasonal allergies and perennial allergies? – Parents (
  3. Perspectives on Second-Generation OTC Antihistamines – Pharmacy Times 30 March 2012 ( [online] 30 March 2012 [cited November 2022]
  4. Dr Corli Lodder – Allergy Clinic in Boksburg, Johannesburg (unpaid interview via email conducted on 10 October 2018)
  5. Web MD – Do I need antihistamines for allergies? ( [online] 24 January 2022 [cited November 2022]
  6. Alfaro, V. Role of histamine and platelet-activating factor in allergic rhinitis. Journal of physiology and biochemistry60(2):101-11 · July 2004 ( [online] July 2004 [cited November 2022]
  7. Picado C. Rupatadine: pharmacological profile and its use in the treatment of allergic disorders. Expert Opinion in Pharmacotherapy 2006; 7(14):1989-2001.