Microplastics and Misinformation: What Science Really Says
November 12, 2025
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Brand Name :
Aldex AN, Unisom
Synonyms :
doxylamine
Class :
Sedatives & Hypnotics Miscellaneous anxiolytics
Brand Name :
Aldex AN, Unisom
Synonyms :
doxylamine
Class :
Sedatives & Hypnotics Miscellaneous anxiolytics
Dosage forms and strengths Â
tablet Â
25 mgÂ
Dosage forms and strengthsÂ
tablet Â
25 mgÂ
Refer adult dosingÂ
benzylpenicilloyl polylysine: they may decrease the diagnostic effect of antihistamines
it increases the effect of CNS depressants
it increases the effect of CNS depressants
it increases the effect of CNS depressants
it increases the effect of CNS depressants
it increases the effect of CNS depressants
may have an increased CNS depressive effect when combined with CNS depressants
may have an increased CNS depressive effect when combined with CNS depressants
may have an increased CNS depressive effect when combined with CNS depressants
may have an increased CNS depressive effect when combined with CNS depressants
may have an increased CNS depressive effect when combined with CNS depressants
may have an increased CNS depressant effect when combined with CNS depressants
may have an increased CNS depressant effect when combined with CNS depressants
may have an increased CNS depressant effect when combined with CNS depressants
doxylamine: they may increase the CNS depressant effect of CNS Depressants
doxylamine: they may increase the CNS depressant effect of CNS Depressants
doxylamine: they may increase the CNS depressant effect of CNS Depressants
It may enhance sedation when combined with a shepherd's purse
when ajmaline is used together with doxylamine, the risk or seriousness of QTc prolongation is enhanced
MAO inhibitors increase the anticholinergic action of doxylamine
MAO inhibitors increase the anticholinergic action of doxylamine
MAO inhibitors increase the anticholinergic action of doxylamine
MAO inhibitors increase the anticholinergic action of doxylamine
MAO inhibitors increase the anticholinergic action of doxylamine
It may enhance the risk of adverse effects when combined with Antihistamines
It may enhance the risk of adverse effects when combined with Antihistamines
It may enhance the risk of adverse effects when combined with Antihistamines
When doxylamine is used together with adenosine, this leads to enhanced risk or seriousness of QTc prolongation
When doxylamine is used together with givinostat, this leads to enhanced risk or seriousness of Qtc prolongation
When doxylamine is used together with profenamine, this leads to enhanced risk or seriousness of adverse events
it increases the effect of CNS depressants
it increases the effect of CNS depressants
may increase the CNS depressant effect of CNS depressants
may increase the CNS depressant effect of CNS Depressants
may increase the effects by pharmacodynamic synergism
brexanolone: they may decrease the therapeutic effect of antihistamines
the therapeutic activity of doxylamine may be reduced
the activity of hyoscine may be increased
cinnarizine and dimenhydrinateÂ
this combination will make you feel sleepy or tired when Antihistamines used in combination
Actions and Spectrum:Â
Actions:Â
Antihistamine: doxylamine blocks histamine receptors in the body, preventing the effects of histamine release. This aids in reducing allergy symptoms like sneezing, itching, watery eyes, and a runny nose.Â
Sedation: doxylamine is a potent sedative and can induce drowsiness. It acts on the central nervous system by antagonizing H1 histamine receptors in the brain, leading to a calming effect and aiding in sleep.Â
Spectrum:Â Â
Insomnia: doxylamine is commonly used as an over-the-counter sleep aid to help individuals with occasional sleeplessness or insomnia. Due to its sedative effects, it can promote sleep initiation and improve sleep quality. Â
Allergies: doxylamine is known for its ability to alleviate allergy symptoms like hay fever, allergic rhinitis, and other allergic reactions. This is achieved through its action of inhibiting histamine receptors, leading to a reduction in allergic responses.Â
Frequency not defined Â
Ophthalmic: Blurred vision, diplopiaÂ
Genitourinary: Dysuria, urinary retentionÂ
Gastrointestinal: xerostomia, epigastric pain, dry mucous membranes, diarrhea, constipation, AnorexiaÂ
Central nervous system: vertigo, headache paradoxical central nervous system stimulation, Disorientation, drowsiness, dizzinessÂ
Cardiovascular: Palpitations, tachycardiaÂ
Black Box Warning:Â Â
None
Contraindication/Caution:Â Â
Hypersensitivity: Individuals who have shown hypersensitivity or allergic reactions to doxylamine or any other antihistamines should avoid its use.Â
Asthma: doxylamine can potentially exacerbate asthma symptoms in some individuals, so it is generally not recommended for people with asthma.Â
Glaucoma: doxylamine can increase intraocular pressure, which can be harmful to individuals with glaucoma or other conditions where high intraocular pressure is a concern.Â
Urinary retention: doxylamine can cause urinary retention, so it should be avoided in people with urinary retention issues or conditions that may be affected by this side effect.Â
Prostate enlargement: Men with benign prostatic hyperplasia (enlarged prostate) should use doxylamine with caution due to its potential to exacerbate urinary retention.Â
Severe liver disease: Individuals with severe liver impairment may experience reduced metabolism and clearance of doxylamine, leading to an enhanced risk of adverse events.Â
Concurrent use with other CNS depressants: Combining doxylamine with other central nervous system (CNS) depressants, such as benzodiazepines or opioids, can enhance sedation and respiratory depression, posing a risk to the individual’s health.Â
Pregnancy and breastfeeding: The safety of doxylamine use during pregnancy and breastfeeding is not well-established. It is generally recommended to avoid doxylamine during these periods or consult a healthcare professional before use.Â
Pregnancy warnings:    Â
Pregnancy category: AU TGA pregnancy category: A
US FDA pregnancy category: Not AssignedÂ
Lactation: Excreted into human milk is knownÂ
Pregnancy Categories:        Â
Category A: Studies that were well-controlled and met expectations revealed no risk to the fetus in either the first or second trimester.Â
<b>Category B: There were a lack of studies on pregnant women and no evidence of risk to the fetus in animal experiments.  Â
Category C: there was evidence of risk of adverse effects in animal reproduction studies, and no adequate evidence in human studies must take care of potential risks in pregnant women.   Â
Category D: adequate data with sufficient evidence of human fetal risk from various platforms, but despite the potential risk, and used only in emergency cases for potential benefits.  Â
Category X: Drugs listed in this category outweigh the risks over benefits. Hence these categories of drugs need to be avoided by pregnant women.   Â
Category N: There is no data available for the drug under this category
Pharmacology:Â Â
doxylamine is an antihistamine medication that exerts its pharmacological effects by blocking histamine receptorsÂ
Pharmacodynamics:Â Â
Histamine H1 Receptor Antagonism: doxylamine is a potent antagonist of histamine H1 receptors. Histamine is a neurotransmitter and inflammatory mediator that plays a crucial role in allergic reactions and wakefulness regulation. By blocking H1 receptors, doxylamine prevents the binding of histamine to these receptors, thereby reducing allergic symptoms and promoting sedation.Â
Sedative Effect: One of the main therapeutic uses of doxylamine is as a sleep aid due to its sedative properties. By antagonizing H1 receptors in the central nervous system, doxylamine induces drowsiness and helps promote sleep.  Â
Pharmacokinetics:Â
AbsorptionÂ
doxylamine is well-absorbed when taken orally. After ingestion, it is rapidly absorbed from the gastrointestinal tract and enters the bloodstream. Â
DistributionÂ
doxylamine has a high distribution throughout the body due to its lipophilic nature. Its capability to traverse the blood-brain barrier, thereby enabling it to manifest its sedative effects within the CNS. The drug also distributes into various tissues and organs.Â
MetabolismÂ
doxylamine undergoes hepatic metabolism, primarily via the cytochrome P450 enzyme system. The major metabolic pathway involves N-demethylation to form an active metabolite known as desmethyldoxylamine. This metabolite also contributes to the drug’s sedative effects.Â
Excretion and EliminationÂ
Following metabolism, doxylamine and its metabolites undergo predominant renal elimination from the system. The drug and its metabolites are expelled through the urine, with a minor portion being eliminated through the feces.Â
Administration: Â
Patient information leafletÂ
Generic Name: doxylamineÂ
Why do we use doxylamine? Â
Allergies: doxylamine can help alleviate symptoms of allergies, such as sneezing, runny nose, itchy/watery eyes, and itching of the nose or throat. It blocks the action of histamine, a chemical produced during allergic reactions that causes these symptoms.Â
Insomnia: Due to its sedative effects, doxylamine is often used as a sleep aid for short-term relief of insomnia. Â
Cough and Cold: doxylamine is included in some over-the-counter cold and flu medications to help relieve symptoms like coughing and sneezing. It can also assist with sleep during illness when symptoms are particularly bothersome at night.Â
Nausea and Vomiting: In some cases, doxylamine may be used off-label to help manage nausea and vomiting, especially during pregnancy (under medical supervision).Â
Motion Sickness: doxylamine can be used to prevent motion sickness or reduce its symptoms when taken before travel.Â
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