doxylamine/pyridoxine (dox-il-a-meen peer-ih-dox-een ) Diclegis, Diclectin

 Indications

Treatment of nausea and vomiting during pregnancy

that has not responded to conservative management.

Action

Combination of an antihistamine and a vitamin B6 analog.

Mechanism not known. Therapeutic Effects:

Decreased nausea and vomiting associated with pregnancy. 

Pharmacokinetics

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)

ROUTE ONSET PEAK DURATION

PO unk unk 8–24 hr

Contraindications/Precautions

Contraindicated in: Hypersensitivity to doxylamine

or pyridoxine; Concurrent 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: Asthma;qintraocular pressure

or narrow angle glaucoma; Stenosing peptic ulcer or

pyloroduodenal obstruction; Urinary bladder-neck obstruction;

Pedi: Safety and effectiveness not established.

Adverse Reactions/Side Effects

CNS: drowsiness.

Interactions

Drug-Drug:qrisk of CNS depression with other CNS

depressants including alcohol, other antihistamines,

opioid analgesics, and sedative/hypnotics.

Concurrent use of MAOIsqintensity/duration of adverse

CNS (anticholinergic) reactions.

Route/Dosage

PO (Adults): Day 1—2 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—2 tablets at bedtime on

day 2 and then 1 tablet in the morning on day 3 and 2

tablets in the evening, if symptoms are controlled, continue

this regimen; Day 4, if symptoms persist—1

tablet in the morning, 1 tablet mid-afternoon and 2 tablets

at bedtime (not to exceed four tablets daily).

Availability (generic available)

Delayed-release tablets: doxylamine 10 mg/pyridoxine

10 mg.