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an antihistamine with sedative and anticholinergic effects; used as the succinate salt in the treatment of nasal, eye, and skin manifestations of allergic reactions, including allergic rhinitis, conjunctivitis, and itching, as an ingredient in cough and cold preparations, and in the short-term treatment of insomnia, administered orally.


(dox-il-a-meen peer-ih-dox-een ),


(trade name),


(trade name)


Therapeutic: antiemetics
Pharmacologic: antihistamines
Pregnancy Category: A


Treatment of nausea and vomiting during pregnancy that has not responded to conservative management.


Combination of an antihistamine and a vitamin B6 analog. Mechanism not known.

Therapeutic effects

Decreased nausea and vomiting associated with pregnancy.


Absorption: Well absorbed following oral administration. Food delays/decreases absorption.
Distribution: Doxylamine probably enters breast milk
Metabolism and Excretion: Doxylamine is mostly metabolized by the liver, inactive metabolites are renally excreted. Pyridoxine is a pro-drug, converted to its active metabolite by the liver.
Half-life: Doxylamine—12.5 hr; pyridoxine—0.4–0.5 hr

Time/action profile (anti-emetic effect)

POunkunk8–24 hr


Contraindicated in: Hypersensitivity to doxylamine or pyridoxineConcurrent use of MAOIs Lactation: Doxylamine probably enters breast milk and may cause irritability, excitement, or sedation in infants; breast feeding should be avoided.
Use Cautiously in: AsthmaIncreased intraocular pressure or narrow angle glaucomaStenosing peptic ulcer or pyloroduodenal obstructionUrinary bladder-neck obstruction Pediatric: Safe and effective use in children <18 yr has not been established

Adverse Reactions/Side Effects

Central nervous system

  • drowsiness (most frequent)


Drug-Drug interaction

↑ risk of CNS depression with other CNS depressants including alcohol, other antihistamines, opioid analgesics, and sedative/hypnotics Concurrent use of MAOIs ↑ intensity/duration of adverse CNS (anticholinergic) reactions


Oral (Adults) Day 1—Two tablets (doxylamine 10 mg/pyridoxine 10 mg) at bedtime, if symptoms are controlled continue this regimen; Day 2, if symptoms persist into afternoon on day 2—two tablets at bedtime on day 2 and then one tablet in the morning on day 3 and two tablets in the evening, if symptoms are controlled, continue this regimen; Day 4, if symptoms persist—one tablet in the morning, one tablet mid-afternoon and two tablets at bedtime (not to exceed four tablets daily).


Delayed-release tablets: doxylamine 10 mg/pyridoxine 10 mg

Nursing implications

Nursing assessment

  • Assess for frequency and amount of emesis daily during therapy. Reassess need for medication as pregnancy progresses.

Potential Nursing Diagnoses

Nausea (Indications)
Risk for injury (Adverse Reactions)


  • Oral: Administer on an empty stomach with a full glass of water; food delays onset of medication. Swallow tablets whole; do not crush, break, or chew.

Patient/Family Teaching

  • Instruct patient to take as directed.
  • May cause drowsiness. Caution patient to avoid driving and other activities requiring alertness until response to medication is known.
  • Advise patient to avoid alcohol and CNS depressants, including sedatives, tranquilizers, antihistamines, opioids, and some cough and cold medications with doxylamine pyridoxine.
  • Instruct patient to notify health care professional of all Rx or OTC medications, vitamins, or herbal products being taken and consult health care professional before taking any new medications.
  • Advise female patient to avoid breast feeding during therapy.

Evaluation/Desired Outcomes

  • Decrease in frequency of nausea and vomiting during pregnancy.


/dox·yl·amine/ (dok-sil´ah-mēn) an antihistamine with anticholinergic and sedative effects, used as the succinate salt.


an antihistamine used in the treatment of allergic reactions and laminitis in cattle and horses.
References in periodicals archive ?
In Canada, where the drug is known as Diclectin, it is prescribed at least once for every two births.
49) A generic form of doxylamine/pyridoxine, Diclectin, remained on the market in Canada, where it continues to be first-line therapy for NVP.
Duchesnay, a pharmaceutical company that markets Diclectin,PregVit, Pregvit Folic5 and Proctofoam-HC, has signed a distribution contract with Tzamal Medical Group, a provider of Medical Devices, Equipment and Pharmaceuticals for the Global Healthcare Industry & veterinary field, it is reported today.
But this combination has been shown to be safe in large studies conducted since that time, and has been approved and available continuously as Diclectin in Canada.
A Canadian company has since disproved the causes of the scare and it is now being reintroduced here under the name Diclectin.
The Canadian company Duchesnay will soon market the drug called Diclectin in the U.
Doxylamine/pyridoxine is currently marketed as Diclegis (US) / Diclectin (Canada) for the treatment of NVP as an oral tablet, dosed up to four times per day and is the only FDA-approved medication to treat this condition.
Because it was off-patent, a Canadian company, Duchesnay, began manufacturing the drug and marketed it as Diclectin in Canada, where it remained available and has been widely used, with a solid safety profile and no evidence of an increased risk of congenital malformations/teratogenicity.
Today, a similar product called Diclectin is sold in Canada and combines vitamin [B.
The combination has been available for years as Diclectin in Canada but, in the United States, could be obtained only as individual OTC components.
Diclectin used for nausea and vomiting of pregnancy does not appear to affect the later neurocognitive development of children who are exposed to the drug in utero, Irena Nulman, M.