'Doxylamine succinate' is one of the many sedating
antihistamines used by itself as a short-term
sleep aid, in combination with other drugs as a night-time
cold and
allergy relief drug, and a preparation is prescribed in combination with
vitamin B6 (
pyridoxine) to prevent
morning sickness in
pregnant women.
Indications
Doxylamine is a member of the
ethanolamine class of antihistamines and has anti-allergy power superior to almost every other antihistamine on the market, with the exception of
diphenhydramine (Benadryl). It is also the most effective over-the-counter sedative available in the
United States, and more sedating than some prescription
hypnotics. In a study, it was found that doxylamine
succinate is possibly more effective than the
barbiturate phenobarbital for use as a sedative. For this reason, doxylamine has sometimes been used off label in a manner similar to diphenhydramine for the reduction of
anxiety symptoms.
The dosage required to induce hypnosis (
sleep) can be as low as 6.25 mg, but is usually effective in dosages of up to 25 mg. Higher doses are not recommended by the United States
Food and Drug Administration, although single dosage recommendations of up to 50 mg are common in countries like Australia, where it is marketed under the names 'Restavit' and 'Dozile'.
Formulations
★ It is one of the active ingredients in '
NyQuil'.
★ In
Commonwealth countries, such as
Australia,
Canada, and the
United Kingdom, doxylamine is available prepared with
paracetamol (acetaminophen) and
codeine under the brand name 'Syndol' or 'Mersyndol', as treatment for
tension headache and other types of
pain.
★ Doxylamine succinate is used in general
over-the-counter sleep-aids branded as 'Somnil', 'Donormyl', 'DSozile', 'Restavit' and 'Unisom-2'.
★ In the
United States doxylamine succinate is the active ingredient in the over-the-counter sleep-aid tablets branded as
Unisom.
★ It is also available in combination with vitamin B
6 and
folic acid under the brand name 'Evanorm' (marketed by Ion Healthcare).
★ In
Canada, doxylamine succinate and
pyridoxine(
vitamin B6) are the ingredients of 'Diclectin', which is used to prevent
morning sickness.
Side effects
Doxylamine succinate is a potent
anticholinergic and has a
side-effect profile common to such drugs, including
dry mouth,
ataxia,
urinary retention, and drowsiness. Other drugs with well known anticholinergic effects include many
antipsychotic and
tricyclic antidepressant drugs.
External links
★
Unisom — manufacturer's website