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Doxylamine is a medication used to manage and treat nausea and vomiting of pregnancy (NVP), allergic rhinitis, and insomnia. It is in the first-generation histamine receptor H1 antagonist class of medications. In the USA, it is available as an over-the-counter medication. This activity reviews the indications, action, and contraindications for doxylamine as a valuable agent in managing nausea and vomiting of pregnancy (NVP), allergic rhinitis, and insomnia. Objectives: Identify the mechanism of action of doxylamine. Describe the potential adverse effects of doxylamine. Summarize the indications for doxylamine use. Review interprofessional team strategies for improving care coordination and communication to advance doxylamine and improve outcomes. Access free multiple choice questions on this topic.

Toxicity associated with antihistamine use is due to overdose following oral ingestion, either unintentional or intentional suicide attempt—most commonly in young and elderly populations. Toxicity from intravenous, intramuscular, or topical routes of administration rarely occurs in the household setting. Toxicity presents as antimuscarinic and hallucinogenic effects. The mnemonic 'dry as a bone, hot as a hare, red as a beet, blind as a bat, full as a flask, and mad as a hatter' has been used to remember the presentation of acute anticholinergic toxicity. This mnemonic represents the findings of anhidrosis, hyperthermia, reddening of the skin, mydriasis, hallucinations, urinary retention, and delirium, respectively. Major complications of doxylamine toxicity include arrhythmias, respiratory failure, seizures, hyperthermia, rhabdomyolysis, and coma. If the patient experiences toxicity, the healthcare team should continually monitor cardiac activity, and IV access is necessary. Patients who only recently ingested the toxic dose can receive activated charcoal.[17][19]

Doxylamine is available both over-the-counter and through a consultation with a physician. It is a first-generation histamine H1 receptor antagonist that can lead to various adverse outcomes if consumed inappropriately. Over-the-counter availability of doxylamine to consumers demands the need to educate patients and the general public on appropriate antihistamine consumption and how to recognize signs of toxicity. Individuals taking doxylamine should understand the potential adverse effects and should receive instruction to store this medication in a secure location where children or other individuals at risk of ingesting a toxic dose (intentionally or unintentionally) cannot access it. Patients should also be counseled on the potential drug interactions with doxylamine, such as increased somnolence and sedation when consumed with alcohol or other central nervous system depressants because of cumulative effects. An interprofessional healthcare team, including clinicians (MDs, DOs, NPS, and PAs), should be well-versed in recognizing the symptoms of doxylamine toxicity. They should be aware of the potential complications that can manifest, such as multiorgan failure and coma. Although most patients experience a full recovery following doxylamine toxicity, it is still vital that healthcare teams are knowledgeable and up to date on the presentation of doxylamine toxicity.[17] The prescribing clinician, along with a pharmacist, should educate the patient regarding dosing and interactions. The pharmacist (as well as nursing) can counsel the patient on administration and potential adverse effects. Nursing can also perform follow-up monitoring and also act as a bridge between the prescriber and the patient. If any one member of the interprofessional team notes an adverse event or therapeutic failure, it should be documented in the patient's health record and communicated to all other team members so appropriate action can take place. These examples of interprofessional collaboration show how to optimize doxylamine therapy for the best clinical results with the fewest adverse events. [Level 5]

An interprofessional healthcare team, including clinicians (MDs, DOs, NPS, and PAs), should be well-versed in recognizing the symptoms of doxylamine toxicity. They should be aware of the potential complications that can manifest, such as multiorgan failure and coma. Although most patients experience a full recovery following doxylamine toxicity, it is still vital that healthcare teams are knowledgeable and up to date on the presentation of doxylamine toxicity.[17] The prescribing clinician, along with a pharmacist, should educate the patient regarding dosing and interactions. The pharmacist (as well as nursing) can counsel the patient on administration and potential adverse effects. Nursing can also perform follow-up monitoring and also act as a bridge between the prescriber and the patient. If any one member of the interprofessional team notes an adverse event or therapeutic failure, it should be documented in the patient's health record and communicated to all other team members so appropriate action can take place. These examples of interprofessional collaboration show how to optimize doxylamine therapy for the best clinical results with the fewest adverse events. [Level 5] Historically, there has been significant debate around a reported correlation between using a combination product containing doxylamine and pyridoxine in the 1970s and congenital disabilities. Media and law firms launched publicity campaigns against the older formulation, which eventually resulted in the discontinuation of the drug for decades until the newer formulation received approval in 2013 for treating NVP refractory to other nonpharmacological management. Approval of the newer formulation was based on randomized, placebo-controlled clinical trials supporting its efficacy and safety. It also considered extensive data concluding that combined treatment with doxylamine succinate and pyridoxine hydrochloride in pregnancy is not teratogenic. This decades-long debate and evidence reinforce the importance of evidence-based medicine. In summary, doxylamine is a generally safe, effective over-the-counter medication that can provide patient benefit with minimal adverse events when used correctly.