REF-1658 · Church et al., 2010 · Allergy, · Paper · PubMed

First-generation H1-antihistamines, every one of them sedating, reduce REM sleep, impair learning and work efficiency and have been implicated in aviation, road and boating accidents, according to a GA2LEN task force that recommends they stop being sold without prescription now that non-sedating second-generation drugs are widely available

Main caveat: No athletes and no exercise outcomes; no numbers in the abstract.
moderate evidenceMeasured on a mixed groupRead from the abstract only

Church and colleagues, writing for a GA2LEN task force, set out to warn regulators, doctors and the public about first-generation H1-antihistamines bought without prescription, which they call the most frequent form of self-medication for allergies, coughs and colds and insomnia.

The task force reviewed the literature in Medline and Embase and went through US media reports from 1996-2008 on accidents and deaths linked to these drugs. It found that all first-generation H1-antihistamines are sedating and are widely seen as safe because they have been used for so long. They cut REM sleep and hamper learning and efficiency at work.

The task force links them to accidents in the air, on the road and on the water, to deaths of infants and young children from accidental or deliberate overdose, and to suicide in teenagers and adults; some harm the heart in overdose.

The authors recommend that these older drugs no longer be sold over the counter for self-medication, because newer non-sedating second-generation antihistamines, which they judge to carry a better balance of risk and benefit, are now easy to buy at competitive cost.

Participants

No participants of its own: a review of the literature and of media reports. The people it concerns are users of over-the-counter first-generation H1-antihistamines, from infants to adults.

Methods

A GA2LEN task force assessed side effects and potential dangers of first-generation H1-antihistamines.
Literature review in Medline and Embase; search terms, dates, inclusion rules and number of studies: not in the abstract.
Media audit: US news reports, 1996-2008, of accidents and fatal adverse events that implicated these drugs.
Grading of evidence or risk of bias: not described in the abstract.

Key Results

All first-generation H1-antihistamines are sedating.
Sleep and thinking: less REM sleep, poorer learning, lower efficiency at work.
Accidents: implicated in civil aviation, road-traffic and boating accidents.
Overdose: deaths in infants and young children from accidental or deliberate overdose, and suicide in teenagers and adults; cardiotoxicity in overdose for some of the drugs.
Laypeople and healthcare professionals generally regard them as safe because of long use, which the task force disputes.
Recommendation: stop over-the-counter sale of the older drugs; newer second-generation non-sedating H1-antihistamines are the alternative.
No numbers (rates, risks or doses) are given in the abstract.

Practical Application

An older, sedating antihistamine is a sedative with costs to sleep and alertness; ask about one before reading a poor night or a flat, clumsy session as fatigue. The task force found these drugs reduce REM sleep and impair learning and work efficiency, and it links them to transport accidents. Reading a flat or clumsy session this way is practice; the paper has no exercise data.
Inference, not tested here: on the day after a dose, a session that needs quick reactions (traffic, group riding, technical descents) carries more risk than an easy or indoor one; the paper reports no exercise data and no timing of effects.
The doctor or pharmacist decides. Whether to move to a non-sedating second-generation antihistamine, which is the task force's own recommendation, is for the prescriber or pharmacist; the assistant does not change, stop or recommend a medication.
Not from this paper: effects on exercise performance, heart rate, heat tolerance or training adaptation; doses, timing and how long the effects last; differences between individual drugs.

Limitations

No athletes and no exercise outcomes; no numbers in the abstract.
A literature review with no search method or evidence grading described, plus a media audit of US reports, which can show that a drug was implicated, not how often harm occurs.
Class-level claims; individual drugs are not named in the abstract.
Published in 2010; rules on over-the-counter sale differ by country and may have changed.
Written from the abstract and the PubMed record; full text not read.
How this entry was checked and changed
Why this level

a position paper not built on a graded systematic review (rubric B+); the abstract gives no study counts or effect sizes, and the accident links rest partly on media reports

Content correction 2026-11-07
2026-11-07: added from the abstract and the PubMed record; level B+ (position paper not built on a graded systematic review). The issuing body is GA2LEN, as in the title and the PubMed record.