The thing about a mother’s instinct is that it’s usually right. So if you have a child who suffers from allergies – be it asthma, eczema or rhinitis – and you have a hunch that the antihistamines he’s on are affecting his behaviour, then you’re probably right too.
The best part? There’s evidence to back your suspicions up because doctors such as paediatrician Dr Paul Sinclair at the Vincent Pallotti Hospital in Cape Town, have seen children react badly to old as well as “safe”, new-generation antihistamines time and time again.
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Back in the day
Taking a look back historically at antihistamines, Dr Sinclair explains that the old-fashioned antihistamines that we all took 30 years ago as children (if we suffered from allergies), were all derivatives of antipsychotic medication.
Chlorpromazine, for example, is an older antipsychotic similar to antihistamines such as Hydroxyzine and Promethazine. All are first-generation antihistamines which, while still around today, are not in favour anymore because they’re fat soluble, they cross the bloodbrain barrier (thus getting into the brain), and they have a heavy sedative effect.
“While these antihistamines are really effective in terms of stopping itching – particularly in those kids who suffer from eczema and urticaria (hives) – they have lots of side effects that include sedation and behavioural changes such as aggression and anxiety,” he cautions.
Yes, first-generation antihistamines sedate children overnight so technically, the side effects should kick in while your child is asleep.
Bear in mind, though, that most antihistamines don’t just stay in the system for eight hours – it’s more like 24 hours – and the more potent ones can even leave your child feeling like he has a hangover when he wakes up in the morning.
“Very strong, first-generation antihistamines can have the same effect as being drunk, and deaden your child’s brain,” he warns. “This is why you need a script for these.”
We have other options
According to Cape Town-based paediatrician and allergologist Dr Sarah Karabus, “The older-generation sedating antihistamines definitely have more side effects than the new generation nonsedating ones and it all depends on what effect one is looking for.”
The difference, explains Dr Sinclair, between the new-generation antihistamines (the so-called second- and third-generation antihistamines) and the older, first-generation antihistamines are the molecules. By making the molecules less fat soluble, they cross over into the brain less, thus making the side effects – sedative and behavioural – less too.
“That said, a lot of children who are on new generation antihistamines still suffer from side effects and I have moms who complain to me that their kids are completely unplayable when on them,” Dr Sinclair explains.
“They maintain that as a result of the (wrong) antihistamine, their kids’ personalities completely change, and that they become hyperactive, anxious and/or even aggressive.” The effect does seem to be compound-dependent, though, says Dr Sinclair.
For example, while he might put one child onto the compound Desloratadine and the results are terrible, Cetirizine for another child could be completely fine and vice versa. It all depends on the child and even within a family, siblings could respond differently to the same antihistamine and have adverse reactions to it, he says.
“The bottom line is that any drug that has an effect on a child, has got to have a potential side effect too, and parents need to be warned about these.
Even the “safe”, new, non-sedating antihistamines can potentially sedate a child, or hype him up so that he doesn’t sleep at all,” he stresses, adding that although uncommon, today’s antihistamines can also make some children twitchy and jerky.
“If you look back at the older generation of these drugs, extrapyramidal side effects can occur, such as twitching and possibly even stiffness.
I have some kids who I can’t even give new-generation antihistamines to as they just twitch and jerk all night on them.”
What to do
If you notice a sudden change in your child’s behaviour or any twitching, aggression, loss of appetite, gain in appetite or problems sleeping, and this ties in with a recent script for his allergy meds, then talk to your doctor.
“The simplest thing to do if you’re concerned that a medication could be causing a problem, is to stop it and see the difference in your child,” advises Dr Sinclair. By doing so, you get rid of the nasty side effects but, as Dr Karabus points out, “Unfortunately, the illnesses that we use antihistamines for – allergies, anaphylaxis, urticaria (hives), rhinitis – also have effects”.
So what’s the alternative? Even though you can buy most second-generation antihistamines over the counter it’s really not advisable. Simply put, it’s better to get a diagnosis from a doctor.
That way, you can attempt to eliminate any triggers rather than just treat the symptoms. Pollen, of course, is a tricky one (bar moving city). But a cat allergy could be easily resolved, a food allergy most certainly avoided and house dust mites, while you can never entirely eliminate them, can be minimised, says Dr Sinclair.
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“Nasal cortisone is also still the mainstay therapy for allergic rhinitis, inhaled cortisone is still the mainstay therapy for asthma and treating the skin appropriately with topical anti-inflammatories is still the mainstay therapy for eczema.
These kinds of treatments form what we call adjunctive therapy (with fewer side effects) and some kids do really well on it and need it,” he continues.
Finally, Dr Sinclair suggests that just because your child has an adverse reaction to a particular antihistamine, you shouldn’t necessarily rule them out altogether because, “the molecules in antihistamines are similar but different.
While some of them might bind to a receptor in a child’s brain and make them ‘horrible’, others won’t go near that receptor and he’ll be absolutely fine”.
That said, if your child absolutely cannot handle any form of antihistamine, then you can get mast cell stabilisers. These stop angry cells from releasing histamine and are fairly effective, particularly in very allergic kids.