Doxylamine succinate is one of the many sedating (Sleep Inducing) antihistamines used by itself as a short-term sedative, and in combination with other drugs as a night-time cold and allergy relief drug.
It is also used in combination with the analgesics paracetamol (acetaminophen) and codeine as an analgesic/calmative preparation, and is prescribed in combination with vitamin B6 (pyridoxine) to prevent morning sickness in pregnant women. It is marketed under various brand names most notably as Dozile and Unisom-2 .
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 is more sedating than some prescription hypnotics. One study found that doxylamine succinate is possibly more effective than the barbiturate phenobarbital for use as a sedative.
The dosage required to induce 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 FDA, although single dosage recommendations of up to 50 mg are common in some countries.
* Doxylamine succinate is the sedating ingredient of NyQuil and Syndol
* In Commonwealth countries, such as Australia, Canada, South Africa and the United Kingdom, doxylamine is available prepared with paracetamol (acetaminophen) and codeine under the brand name Dolased, 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, Dozile, Donormyl, Dormidina, Restavit and Unisom-2.
* In Canada doxylamine succinate is the active ingredient in the over-the-counter sleep-aid tablets branded as Unisom 2; while Unisom contains diphenhydramine hydrochloride as the active ingredient.
* It is also available in combination with vitamin B6 and folic acid under the brand name Evanorm .
* In Canada, doxylamine succinate and pyridoxine (vitamin B6) are the ingredients of Diclectin, which is used to prevent morning sickness.
Doxylamine succinate is a potent anticholinergic and has a side-effect profile common to such drugs, including dry mouth, ataxia, urinary retention, and drowsiness.
Doxylamine succinate is generally safe for administration to healthy adults. Typical preparations that contain doxylamine range from 6.25 mg to 25.0 mg. The LD50 is estimated to be 50â€“500 mg/kg in humans. Symptoms of overdose may include dry mouth, dilated pupils, insomnia, euphoria, hallucinations, seizures, rhabdomyolysis, and death.
Fatalities, while rare, have been recorded. Rarely, an overdose results in rhabdomyolysis and acute renal failure.
Doxylamine Succinate 25 mg Capsules Information: NZ Government's Dozile Data Sheet
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