A fixed-dose combination product primarily indicated for the management of nausea and vomiting in pregnancy (NVP), commonly known as morning sickness. Doxylamine is a first-generation ethanolamine antihistamine with potent antiemetic and sedative properties. Pyridoxine (Vitamin B6) is a cofactor in neurotransmitter synthesis and helps reduce nausea. Folic Acid is included for its crucial role in fetal neural tube development, making this combination a comprehensive therapy for pregnant women in the first trimester.
Adult: For NVP: 1 tablet at bedtime. If symptoms persist into the day, a dosing schedule of 1 tablet at bedtime and 1/2 to 1 tablet in the morning may be used under medical supervision. Maximum: 2 tablets (20mg doxylamine) per day.
Note: Take orally with or without food. Taking at bedtime is recommended to minimize daytime drowsiness. Swallow whole with a glass of water. Do not crush or chew.
The combination works synergistically. Doxylamine antagonizes histamine H1 receptors in the chemoreceptor trigger zone (CTZ) and vomiting center, suppressing the emetic reflex. Pyridoxine modulates neurotransmitters like serotonin and GABA, which are implicated in nausea pathways. Folic Acid provides nutritional supplementation essential for rapid cell division and growth during pregnancy, particularly for neural tube closure in the developing fetus.
Pregnancy: Pregnancy Category A (US FDA). Extensively studied and considered safe and effective for NVP. Recommended by ACOG and FOGSI. Should be used during pregnancy only if clearly needed, under medical supervision, primarily in the first trimester.
Driving: NOT ADVISABLE. Doxylamine causes significant drowsiness and can impair alertness, reaction time, and motor coordination. Patients should not drive or operate heavy machinery for at least 6-8 hours after a dose.
| CNS Depressants (Alcohol, Benzodiazepines, Opioids) | Potentiated sedation, respiratory depression, impaired psychomotor performance. | Major |
| Anticholinergic drugs (Atropine, TCAs, Antipsychotics) | Additive anticholinergic effects (dry mouth, urinary retention, constipation, confusion). | Major |
| MAO Inhibitors (Phenelzine, Tranylcypromine) | Exaggerated anticholinergic and CNS depressant effects, risk of crisis. | Contraindicated |
| Levodopa | Pyridoxine (>5mg) may enhance peripheral metabolism of levodopa, decreasing its efficacy in Parkinsonism. | Moderate |
| Phenytoin, Phenobarbital, Primidone | Folic Acid may decrease serum levels of these antiepileptics, potentially reducing seizure control. | Moderate |
| Methotrexate, Trimethoprim, Pyrimethamine | These are folic acid antagonists. Concurrent use may reduce efficacy of folic acid supplementation. | Moderate |