doxylamine/pyridoxine

Adult Dosing

Nausea and vomiting of pregnancy in women

Initially, take two tablets orally at bedtime (Day 1). If this dose adequately controls symptoms the next day, continue taking two tablets daily at bedtime. If symptoms persist into the afternoon of Day 2, take the usual dose of two tablets at bedtime that night then take three tablets starting on Day 3 (one tablet in the morning and two tablets at bedtime). If these three tablets adequately control symptoms on Day 4, continue taking three tablets daily. Otherwise take four tablets starting on Day 4 (one tablet in the morning, one tablet mid-afternoon and two tablets at bedtime). Tablets should not be taken on an as needed basis. Maximum dose = 4 tablets daily.

Pediatric Dosing

Safety and effectiveness in children < 18 years of age have not been established

[Outline]

Adult Dosing
Pediatric Dosing

Indications ⬆ ⬇

Treatment of nausea and vomiting of pregnancy in women who do not respond to conservative management

Contraindications ⬆ ⬇

Hypersensitivity to any of the ingredients of the product
Known hypersensitivity to other ethanolamine derivative antihistamines
Monoamine oxidase (MAO) inhibitors

Black Box Warnings ⬆ ⬇

Dosing Adjustment ⬆ ⬇

Renal Dose Adjustment

Renal impairment: Dose adjustments not defined; use with caution

Hepatic Dose Adjustment

Hepatic impairment: Dose adjustments not defined; use with caution

Warnings/Precautions ⬆ ⬇

Therapy may lead to somnolence due to the anticholinergic properties of doxylamine succinate. Women should avoid engaging in activities requiring complete mental alertness, such as driving or operating heavy machinery
Coadministration with alcohol and other CNS depressants may cause additive sedation and is not recommended; combination may cause severe drowsiness leading to falls or accidents
Drug has anticholinergic properties, use cautiously in women with: asthma, increased intraocular pressure, narrow angle glaucoma, stenosing peptic ulcer, pyloroduodenal obstruction and urinary bladder-neck obstruction

Pregnancy/Breast Feeding ⬆ ⬇

Pregnancy Category:A

Breastfeeding: Women should not breastfeed while on therapy. The molecular weight of doxylamine succinate is low enough that it may pass into breast milk. Pyridoxine hydrochloride is excreted into breast milk.

Adverse Reactions ⬆ ⬇

Clinical Pharmacology ⬆ ⬇

First generation antihistamines; mechanism of action for efficacy for morning sickness is unknown
Extensively metabolized by liver by N-dealkylation to its principle metabolites N-desmethyldoxylamine and N, N-didesmethyldoxylamine
Excreted primarily in urine
Half life: 12.5 hrs
Vitamin B6 analog; mechanism of action for efficacy for morning sickness is unknown
Metabolized in the liver to pyridoxal 5’-phosphate (PLP), pyridoxal, pyridoxamine, and pyridoxamine 5’-phosphate
Half life: 0.5 hrs

Brands and Availability ⬆ ⬇