Title. Mistankenly took one 25mg dose of Atarax about 4h ago. Started feeling very... tired, and still do. When will the effect wear off? I can't work like this... Any 'risks' from having taken one dose randomly like that? Thanks.
Hydroxyzine Hydrochloride (Atarax, Ucerax) is a first-generation (sedative) antihistamine. Drugs of this type tend to have a pretty tame clinical profile, and it's unlikely you will experience any undesirable effects, apart from the sedation.
Without knowing your medical history, it can be difficult to ascertain whether you will suffer any drug-drug or drug-disease reactions.
You may find coffee (caffeine) can help to counteract the sedative/hypnotic effect, although this will not reverse the effects of the antihistamine. According to this document, the amount of Hydroxyzine Hydrochloride (Atarax) in the body will half within 14-24 hours.
It's recommended you do not drive or operate heavy machinery without first assessing your ability to concentrate under influence of the medication, or while the drug is still in your system.