Doxylamine (medication): uses, indications and side effects
This drug is often prescribed for insomnia.
Doxylamine is a drug that is mainly used to treat the symptoms of short-term insomnia.It is an antihistamine drug, as it facilitates and improves sleep. It is an antihistamine drug (blocking histamine H1 receptors).
Histamine is related to allergic symptoms. In this article we will learn about doxylamine, its general characteristics, indications, side effects, precautions, etc. In addition, we will also talk about insomnia.
- Recommended article: "The 12 types of insomnia (according to their duration, severity and symptoms)".
Doxylamine: general characteristics
Doxylamine is an antihistamine drug.. Specifically, it belongs to the group of H1 antihistamines. Its main indication is the treatment of short-term insomnia. However, it also has other uses, such as the treatment of coughs and colds (it is usually combined with decongestants).
In its commercial format, it is common to find it in sachets (in powder form that dissolves in water). It can also be found in tablet form. All of these are taken orally.
Doxylamine, as well as other antihistamines of its group (H1), crosses the blood-brain barrier. Then, it causes drowsiness in the individual, since it inhibits the H1 receptors in charge of stimulating wakefulness. This is why it is effective in treating insomnia. Doxylamine can be purchased in pharmacies, and in Spain no prescription is required.
Mechanism of action
Doxylamine is an antihistamine; it is derived from ethanolamine, an organic chemical compound. Its activity is based on a competitive, reversible and non-specific antagonist action of the histamine H1 receptors..
Thus, doxylamine, as an antihistamine, acts by blocking the action of histamine; histamine is a substance in the body that causes Allergy symptoms. Specifically, histamine is found naturally in the cells of our immune system (mainly in mast cells and basophils).
Because histamine causes allergy symptoms, antihistamines are prescribed to alleviate allergy symptoms (because they block its action). Doxylamine is effective in reducing the time in which a person falls asleep; it also increases the depth and duration of sleep.
Let us remember that pharmacokinetics is a branch of pharmacology, in charge of studying the processes to which a drug is subjected when it is introduced and distributed in the organism. It has to do with the metabolism of drugs, their half-life, excretion....
In the case of doxylamine, we know that its metabolism is hepatic (liver). Its half-life is 6 to 12 hours (the half-life of a drug is the time it takes for it to be reduced by half in the body). Its excretion is 60% in urine and 40% in feces..
Mode of administration
Doxylamine is administered orally in tablet form.. These should be taken 30 minutes before going to sleep. They are ideally taken with liquid (water). Doxylamine can also be taken in sachets (powder), pouring its contents on the tongue.
On the other hand, as for meals, it can be taken before or after meals.
The use of doxylamine is indicated for persons over 18 years of age.. The main indication of doxylamine is the short-term treatment of insomnia. Insomnia disorder involves difficulty falling asleep (onset insomnia) and/or maintaining sleep (maintenance insomnia).
In addition, people with insomnia sometimes wake up prematurely (terminal insomnia).
Other indications for doxylamine are: treatment of the common cold (helps to relieve symptoms such as sneezing, runny nose and nasal congestion), as well as treatment of cough. Doxylamine is usually taken in combination with decongestant products or drugs.
Insomnia disorder: what is it?
Since the main indication for doxylamine is the treatment of insomnia, we are going to see, broadly speaking, what it is, let's see, broadly speaking, what this sleep disorder consists of, which can interfere so much in a person's life..
Insomnia disorder (primary insomnia), defined as such in the DSM-5 (Diagnostic Manual of Mental Disorders) involves difficulty initiating or maintaining sleep. It also makes it difficult to have a restful sleep.
The symptoms last at least 1 month. On the other hand, the sleep disturbances caused by this disorder (or the associated daytime fatigue) lead to significant discomfort for the individual (or functional impairment).
According to ICD-10 (International Classification of Diseases), the symptoms of primary insomnia must appear at least 3 times a week (also for at least one month, as in the DSM-5).
This disorder is more prevalent with increasing age, and is also more prevalent in women. Primary insomnia is the most prevalent sleep-related disorder worldwide (an estimated 1-10% of the adult population suffers from it).
Some considerations and precautions to be aware of regarding doxylamine are: doxylamine should not be administered to induce sleep in children; nor should it be taken with alcoholic beverages or grapefruit juice..
As we mentioned at the beginning, it should be administered from 18 years of age onwards, never in minors. It should not be administered for more than 7 days (it is a short-term pharmacological treatment).
Other aspects to know about doxylamine are that we should reduce its dose (or advance its intake) in case of daytime drowsiness.
Also we should also be cautious with doxylamine in case of epilepsy, cardiac insufficiency, being an elderly person, urinary obstruction or urinary retention.or if you have urinary obstruction or retention, etc.
We should know that this drug could worsen the symptoms of dehydration or heat stroke (this is due to the reduction of sweating generated by the anticholinergic effects of the drug).
Pregnancy and lactation
Doxylamine is contraindicated in case of pregnancy. As for breastfeeding, it is not recommended, since it is very likely that doxylamine is excreted in breast milk and the baby may be sensitive to the effects of antihistamines. Thus, there would be risk for the baby.
The side effects that doxylamine may cause are as follows: headache, agitation, nausea, drowsiness, dry mouth, nose and throat, nervousness, and increased nervousness.nervousness and increased breast engorgement.
On the other hand, there are two adverse effects of doxylamine that can be serious, and that is why it is necessary to call an emergency room if they occur; these are: vision problems and urination difficulties.
On the other hand, the adverse reactions that doxylamine can cause are: dry mouth, drowsiness, constipation, urinary retention, vertigo, blurred vision and increased bronchial secretion.
American Psychiatric Association -APA- (2014). DSM-5. Diagnostic and statistical manual of mental disorders. Madrid: Panamericana.
WHO (2000). ICD-10. International classification of diseases, tenth edition. Madrid. Panamericana.
Stahl, S.M. (2002). Essential psychopharmacology. Neuroscientific bases and clinical applications. Barcelona: Ariel.
Vademecum. (2018). Doxylamine.
(Updated at Mar 28 / 2023)