Oxomemazine/guaifenesin is a sedative antihistamine plus expectorant. It is a combination of oxomemazine and guaifenesin. It is sold under a variety of brand names including Toplexil by Aventis. It is sold over the counter in France, Egypt, Algeria, South Korea and the UAE. The oxomemazine ingredient (antihistamine) is not approved by the U.S. Food and Drug Administration (FDA), either for over the counter or prescription use. French travelers use it as a sleeping aid for long flights.