PRESCRIBING INFORMATION

Xonvea 10 mg/10 mg gastro-resistant tablets:
Please refer to full Summary of Product Characteristics (SmPC) before prescribing.

Presentation:
Gastro-resistant tablets containing 10 mg doxylamine succinate and 10 mg pyridoxine hydrochloride.

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

Dosage:
Refer to SmPC for full dosage information.

Posology:
The recommended starting dose is two tablets at bedtime (Day 1). If this dose adequately controls symptoms the next day, the patient can continue taking two tablets at bedtime. However, if symptoms persist into the afternoon of Day 2, the patient should continue the usual dose of two tablets at bedtime (Day 2) and on Day 3 take three tablets (one tablet in the morning and two tablets at bedtime). If these three tablets do not adequately control symptoms on Day 3, the patient can take four tablets starting on Day 4 (one tablet in the morning, one tablet mid afternoon and two tablets at bedtime). The maximum recommended daily dose is four tablets (one in the morning, one in the mid-afternoon and two at bedtime). Xonvea should be taken as a daily prescription and not on an as needed basis. Continued need for Xonvea should be reassessed as the pregnancy progresses. To prevent a sudden return of nausea and vomiting of pregnancy symptoms, a gradual tapering dose of Xonvea is recommended at the time of discontinuation.

Paediatric population:
Xonvea is not indicated for use in children under 18 years of age.

Method of administration:
Xonvea should be administered on an empty stomach with a glass of water. The tablets should be swallowed whole and should not be crushed, split or chewed.

Contra-indications:
Hypersensitivity to doxylamine succinate, other ethanolamine derivative antihistamines, pyridoxine hydrochloride or any of the excipients. Refer to SmPC for full list. Concomitant use with monoamine oxidase inhibitors (MAOIs).

Warning and Precautions:
Xonvea may cause somnolence due to the anticholinergic properties of doxylamine succinate, an antihistamine. Use of Xonvea is not recommended if a woman is concurrently using central nervous system (CNS) depressants, including alcohol. Xonvea has anticholinergic properties and, therefore, should be used with caution in patients with: asthma, increased intraocular pressure, narrow angle glaucoma, stenosing peptic ulcer, pyloroduodenal obstruction and bladder-neck obstruction. Xonvea contains pyridoxine hydrochloride, a vitamin B6 analogue, therefore additional levels from diet and vitamin B6 supplements should be assessed. Xonvea contains traces of azo colouring agent Allura Red Ac Aluminium Lake (E129) which may cause allergic reaction. There is limited evidence in cases of hyperemesis gravidarum for the combination doxylamine/pyridoxine. These patients should be treated by a specialist. There have been reports of false positive urine screening tests of methadone, opiates and phencyclidine phosphate (PCP) with doxylamine succinate/pyridoxine hydrochloride. Xonvea has a moderate to major influence on the ability to drive and use machines. Women should avoid engaging in activities requiring complete mental alertness, such as driving or operating heavy machinery, while using Xonvea until cleared to do so by their healthcare provider.

Overdose:
Refer to SmPC for full details. Signs and symptoms may not be apparent immediately. Management should be in accordance with established treatment guidelines. A toxic dose for children of more than 1.8 mg/kg has been reported.

Interactions:
Monoamine oxidase inhibitors (MAOIs) prolong and intensify the anticholinergic effects of antihistamines. Concurrent use with central nervous system (CNS) depressants including alcohol, hypnotic sedatives and tranquilizers is not recommended. The combination may result in severe drowsiness. A food-effect study has demonstrated the delay in the onset of action of Xonvea may be further delayed, and a reduction in absorption may occur when tablets are taken with food. Therefore, Xonvea should be taken on an empty stomach with a glass of water. False positive urine drug screens for methadone, opiate and PCP can occur with doxylamine succinate/pyridoxine hydrochloride use. Confirmatory tests, such as Gas Chromatography Mass Spectrometry (GC-MS) should be used to confirm the identity of the substance in the event of a positive immunoassay result.

Pregnancy and Lactation:
The molecular weight of doxylamine succinate 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 succinate through breast milk. Infants with apnoea or other respiratory syndromes may be particularly vulnerable to the sedative effects of Xonvea resulting in worsening of their apnoea or respiratory conditions. Pyridoxine hydrochloride is excreted into breast milk. There have been no reports of adverse events in infants presumably exposed to pyridoxine hydrochloride through breast milk.

Pregnancy:
Xonvea is intended for use in pregnant women. A large amount of data on pregnant women indicates no malformative nor feto/neonatal toxicity of doxylamine succinate and pyridoxine hydrochloride.

Undesirable Effects:
Very common (≥1/10): somnolence. Common (≥1/100<1/10): dizziness, dry mouth, fatigue. Not known (cannot be estimated from the available data): hypersensitivity, anxiety, disorientation, insomnia, nightmares, headache, migraines, paresthesia, psychomotor hyperactivity, vision blurred, visual disturbances, vertigo, dyspnea, palpitation, tachycardia, abdominal distention, abdominal pain, constipation, diarrhoea, hyperhidrosis, pruritus, rash, rash maculo-papular, dysuria, urinary retention, chest discomfort, fatigue, irritability, malaise. Refer to SmPC for full list.

Legal Category: POM

Packs sizes and NHS price: 20 gastro-resistant tablets £28.50.

Marketing Authorisation number: PL 16853/0147.

Marketing Authorisation Holder:Alliance Pharmaceuticals Limited, Avonbridge House, Bath Road, Chippenham, Wiltshire, SN15 2BB, UK.

Date of preparation/last revised: February 2020.

Adverse Event Reporting
Adverse events should be reported. Reporting forms and information can be found at www.mhra.gov.uk/yellowcard or search for MHRA Yellowcard in the Google Play or Apple App Store. Adverse events should also be reported to Alliance Pharmaceuticals
(tel 01249 466966, email: pharmacovigilance@alliancepharma.co.uk)