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 has demonstrated efficacy in reducing mild to moderate nausea. Folic Acid is included for its crucial role in fetal neural tube development, making this combination a comprehensive therapy targeting both symptoms and prophylaxis in the first trimester.
Adult: For NVP: 1 tablet at bedtime. If symptoms persist, may increase to 1 tablet in the morning and 1 tablet at bedtime. Maximum: 2 tablets per day (Doxylamine 20mg, Pyridoxine 20mg, Folic Acid 5mg).
Note: Take orally with or without food. Taking at bedtime is recommended to capitalize on sedative effect and manage morning symptoms. 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 nausea and vomiting. Pyridoxine's exact antiemetic mechanism is unclear but may involve modulation of neurotransmitter levels (GABA, serotonin) and correction of a relative deficiency. Folic Acid provides the necessary substrate for DNA synthesis and neural tube closure in the developing fetus.
Pregnancy: Pregnancy Category A (US FDA). Extensively studied and considered safe and effective for NVP. The combination of doxylamine and pyridoxine is a US FDA-approved treatment for NVP. Folic Acid is recommended for all women of childbearing potential to prevent neural tube defects. Use during pregnancy should be under medical supervision.
Driving: NOT ADVISABLE. Doxylamine causes significant drowsiness and impairs alertness, reaction time, and coordination. Patients should not drive or operate heavy machinery for at least 6-8 hours after a dose, or until individual response is known.
| CNS Depressants (Alcohol, Benzodiazepines, Opioids, Barbiturates) | Additive sedation, respiratory depression, impaired psychomotor performance. | Major |
| Anticholinergic Agents (Tricyclic Antidepressants, Atropine, Oxybutynin) | Increased risk of anticholinergic side effects (dry mouth, urinary retention, constipation, confusion). | Major |
| Monoamine Oxidase Inhibitors (MAOIs) e.g., Phenelzine, Selegiline | Exaggerated anticholinergic and CNS depressant effects; hypertensive crisis possible. | Contraindicated |
| Levodopa | Pyridoxine (at high doses >5mg) can increase peripheral metabolism of levodopa, reducing its efficacy. Not significant at this dose. | Moderate |
| Phenytoin, Phenobarbital, Primidone | Folic Acid may decrease serum levels of these anticonvulsants, potentially reducing seizure control. | Moderate |
| Methotrexate | Folic Acid may reduce the hematological toxicity of methotrexate but can also interfere with its efficacy in cancer chemotherapy (not in rheumatoid arthritis or psoriasis). | Major (in cancer therapy) |
Same composition (Doxylamine (10mg) + Vitamin B6 (Pyridoxine) (10mg) + Folic Acid (2.5mg)), different brands: