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Doxylamine with pyridoxine


Oral formulations of doxylamine succinate with pyridoxine hydrochloride.

Drugs List

  • doxylamine 10mg and pyridoxine 10mg gastro-resistant tablets
  • XONVEA 10mg+10mg gastro-resistant tablets
  • Therapeutic Indications


    Severe vomiting during pregnancy

    Nausea and vomiting during pregnancy in women who do not respond to conservative management.


    To be taken as a daily prescription and not on an as needed basis.


    Initial dose (day one): Two tablets at bedtime

    Maintenance dose (day two onwards):

    Symptoms controlled: continue with initial dose of two tablets at bedtime.

    Symptoms persist: continue with two tablets at bedtime on day two but from day three, increase the dose to one tablet in the morning and two tablets at bedtime.

    If this increased dose fails to manage symptoms, a further increase may be made on day four to one tablet in the morning, one tablet at midday and two tablets at bedtime.


    Children under 18 years

    Precautions and Warnings

    Bladder outflow obstruction
    Narrow angle glaucoma
    Pyloroduodenal obstruction
    Raised intra-ocular pressure
    Stenosing peptic ulcer

    Advise ability to drive/operate machinery may be affected by side effects
    Reassess need for continued treatment at regular intervals
    May affect results of some laboratory tests
    To discontinue, reduce dose gradually
    Advise that effects are potentiated by CNS depressants (including alcohol)

    Whilst high doses of pyridoxine pose little risk to the foetus, the manufacturer advises that additional intake of vitamin B6 from supplements and/or diet is assessed.

    Pregnancy and Lactation


    Doxylamine and pyridoxine is intended for use in pregnant women.

    A large amount of data on pregnant women indicates no malformative nor foetal neonatal toxicity with doxylamine and pyridoxine.

    The use of all medication in pregnancy should be avoided whenever possible; particularly in the first trimester. Non-drug treatments should also be considered. When essential, a medication with the best safety record over time should be chosen, employing the lowest effective dose for the shortest possible time. Polypharmacy should be avoided. Teratogens taken in the pre-embryonic period, often quoted as lasting until 14 to 17 days post-conception, are believed to have an all-or-nothing effect. Where drugs have a short half-life, and when the date of conception is certain, this may allow women to be reassured where drug exposure has occurred within this time frame. Further advice may be available from the UK National Teratology Information Service (NTIS) and through ToxBase, available via password on the internet ( ) or if this is unavailable at the backup site ( ).


    Use doxylamine with pyridoxine with caution in breastfeeding.

    The effects of doxylamine and pyridoxine as a combined drug during breastfeeding are unclear.

    The molecular weight of doxylamine is low enough that passage into breast milk can be expected. Excitement, irritability and sedation have been reported in nursing infants presumably exposed to doxylamine through breast milk, particularly following high doses or prolonged use. Infants with apnoea or other respiratory syndromes may be particularly vulnerable to sedative effects.

    Pyridoxine is excreted into breast milk. There have been no reports of adverse events in infants presumably exposed to pyridoxine through breast milk.

    A risk to breastfed infants cannot be excluded.

    The manufacturer advises either discontinuing breastfeeding or discontinuing or abstaining from doxylamine and pyridoxine therapy.

    Neonates, infants born prematurely, those with low birth weight, those with an unstable gastrointestinal function or who have serious illnesses may require special consideration. For any infant, if a drug is prescribed to the nursing mother, it should be at the lowest practical dose and for the shortest time. When drug administration is unavoidable and breastfeeding is to continue, minimisation of exposure of the infant to the drug may sometimes be achieved by timing the maternal doses to just after a feeding episode. Infants exposed to drugs via breast milk should be monitored for unusual signs or symptoms. Interactions between the drug received by the infant from the mother's milk and medication prescribed for the infant should also be considered, for example, when the drug given to the infant may prevent metabolism of the drug received via breast milk.
    Specialist advice is available from the UK Drugs in Lactation Advisory Service at

    Side Effects

    Abdominal distension
    Abdominal pain
    Acute labyrinthitis
    Blurred vision
    Chest discomfort
    Chest tightness
    Dry mouth
    Dry throat
    Early menses
    Haemolytic anaemia
    Hypersensitivity reactions
    Increased appetite
    Maculopapular rash
    Nasal dryness
    Nasal stuffiness
    Psychomotor hyperactivity
    Thickening of bronchial secretions
    Toxic psychosis
    Urinary retention
    Visual disturbances
    Weight gain

    Effects on Laboratory Tests

    Laboratory tests may be affected by the use of doxylamine with pyridoxine, including false positive urine screens for methadone, opiates and phencyclidine phosphate (PCP). In the event of a positive immunoassay result, a confirmatory test such as Gas Chromatography Mass Spectrometry should be used to identify the substance.


    It is strongly recommended that the UK National Poisons Information Service be consulted on cases of suspected or actual overdose where there is doubt over the degree of risk or about appropriate management.

    The following number will direct the caller to the relevant local centre (0844) 892 0111

    Information may be obtained if you have access to ToxBase the primary clinical toxicology database of the National Poisons Information Service. This is available via password on the internet ( ) or if this is unavailable at the backup site ( ).

    Further Information

    Last Full Review Date: August 2018

    Reference Sources

    Drugs During Pregnancy and Lactation: Treatment Options and Risk Assessment, 3rd edition (2015) ed. Schaefer, C., Peters, P. and Miller, R. Elsevier, London.

    Drugs in Pregnancy and Lactation: A Reference Guide to Fetal and Neonatal Risk, 10th edition (2015) ed. Briggs, G., Freeman, R. Wolters Kluwer Health, Philadelphia.

    Summary of Product Characteristics: Xonvea 10mg/ 10mg gastro-resistant tablets. Alliance Pharmaceuticals Ltd. Revised December 2019.

    US National Library of Medicine. Toxicology Data Network. Drugs and Lactation Database (LactMed).
    Doxylamine Available at:
    Last revised: 04 June 2018
    Last accessed: 29 August 2018

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