Doxylamine

Brand names: Aldex® ANEquate® Sleep AidNitetime™Unisom® SleepTabs™Wal-Som

Chemical formula:

Drug Forms:
• Doxylamine tablets (below)
• Doxylamine Succinate Chewable tablet
• Doxylamine Succinate Oral tablet
• Doxylamine Succinate Oral tablet [Insomnia]
• Doxylamine Succinate, Tannic Acid Oral suspension
• Doxylamine Succinate Oral solution

Español:
• Tabletas de doxilamina
• Succinato de doxilamina, Tableta masticable
• Succinato de doxilamina, Tableta oral
• Succinato de doxilamina, Tableta oral [Insomnio]
• Succinato de doxilamina, Ácido tánico, Suspensión oral
• Succinato de doxilamina, Solución oral

Doxylamine tablets

What are Doxylamine tablets?

DOXYLAMINE (Unisom® Sleeptabs™) is an antihistamine commonly used as a nighttime sleep aid. This drug is also used to relieve symptoms of hay fever (allergic rhinitis), hives (rash or itching), and other allergic reactions. Generic doxylamine tablets are available.

What should I tell my health care provider before I take this medicine?

They need to know if you have any of these conditions:
• asthma or chronic obstructive lung disease (COPD)
• glaucoma
• high blood pressure or heart disease
• liver disease
• other chronic illness
• prostate trouble
• pain or difficulty passing urine
• ulcers or other stomach problems
• an unusual or allergic reaction to doxylamine, other medicines foods, dyes, or preservatives
• pregnant or trying to get pregnant
• breast-feeding

How should this medicine be used?

Take doxylamine tablets by mouth. Follow the directions on the label. Take doxylamine with food or milk if it upsets your stomach. Take your doses at regular intervals. Do not take your medicine more often than directed.

If you take doxylamine to help you sleep, take the dose no more than once per day about 30 minutes before bedtime. If you continue to have trouble sleeping after 2 weeks of using doxylamine, contact your health care provider.

Contact your pediatrician or health care professional regarding the use of this medicine in children. Special care may be needed.

What drug(s) may interact with Doxylamine?

• alcohol
• barbiturate medicines for inducing sleep or treating seizures (convulsions)
• medicines for anxiety or sleeping problems, such as diazepam or temazepam
• medicines for hay fever and other allergies
• medicines for mental depression
• medicines for mental problems and psychotic disturbances
• muscle relaxers
• prescription pain medicines

Tell your prescriber or health care professional about all other medicines you are taking, including non-prescription medicines, nutritional supplements, or herbal products. Also tell your prescriber or health care professional if you are a frequent user of drinks with caffeine or alcohol, if you smoke, or if you use illegal drugs. These may affect the way your medicine works. Check with your health care professional before stopping or starting any of your medicines.

What should I watch for while taking Doxylamine?

You should not take doxylamine to help you sleep for more than 2 weeks without first consulting your health care professional.

Tell your prescriber or health care professional if you are taking doxylamine for cold or allergy symptoms and there is no improvement in 1 or 2 days, or if you develop a high fever, have difficulty breathing, or your symptoms worsen.

You may get drowsy or dizzy. Do not drive, use machinery, or do anything that needs mental alertness until you know how doxylamine affects you. To reduce the risk of dizzy or fainting spells, do not stand or sit up quickly, especially if you are an older patient. Alcohol may increase dizziness and drowsiness. Avoid alcoholic drinks.

Your mouth may get dry. Chewing sugarless gum or sucking hard candy, and drinking plenty of water will help.

Doxylamine may cause dry eyes and blurred vision. If you wear contact lenses you may feel some discomfort. Lubricating drops may help. See your ophthalmologist if the problem does not go away or is severe.

What side effects may I notice from receiving Doxylamine?

Side effects that you should report to your prescriber or health care professional as soon as possible:
• agitation, nervousness, excitability, not able to sleep (these are more likely in children)
• blurred vision
• dizziness or fainting spells
• irregular heartbeat, palpitations, or chest pain
• muscle or facial twitches
• pain or difficulty passing urine
• seizures (convulsions)

Side effects that usually do not require medical attention (report to your prescriber or health care professional if they continue or are bothersome):
• drowsiness, dizziness
• dry mouth
• headache
• loss of appetite
• stomach upset, nausea, vomiting, diarrhea, or constipation

Where can I keep my medicine?

Keep out of the reach of children in a container that small children cannot open.

Store at room temperature, between 15 and 30 degrees C (59 and 86 degrees F). Do not freeze. Protect from light. Throw away any unused medicine after the expiration date.

Last updated: 10/22/2003 2:02:00 PM

Important Disclaimer: The drug information provided here is for educational purposes only. It is intended to supplement, not substitute for, the diagnosis, treatment and advice of a medical professional. This drug information does not cover all possible uses, precautions, side effects and interactions. It should not be construed to indicate that this or any drug is safe for you. Consult your medical professional for guidance before using any prescription or over the counter drugs.

An antihistamine used in the treatment of allergic reactions and laminitis in cattle and horses.

Doxylamine

Systematic (IUPAC) name
(RS)-N,N-dimethyl-2- (1-phenyl-1-pyridin-2-yl-ethoxy)- ethanamine
Identifiers
CAS number	469-21-6
ATC code	R06AA09
PubChem	3162
DrugBank	APRD00937
ChemSpider	3050
Chemical data
Formula	C17H22N2O
Mol. mass	270.369 g/mol
SMILES	eMolecules & PubChem
Pharmacokinetic data
Bioavailability	Oral: 24.7%, Intranasal: 70.8% [1]
Metabolism	Hepatic
Half life	variable; 6–12 hours
Excretion	Urine (primarily as metabolites)
Therapeutic considerations
Pregnancy cat.	A(US)
Legal status	OTC
Routes	Oral
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Doxylamine succinate is one of the many sedating antihistamines used by itself as a short-term sedative, in combination with other drugs as a night-time cold and allergy relief drug, in combination with the analgesics paracetamol and codeine as an analgesic / calmative preparation, and is prescribed in combination with vitamin B6 (pyridoxine) to prevent morning sickness in pregnant women.

Contents 1 Indications 2 Metabolites 3 Formulations 4 Side effects 5 Toxicity 6 References

Indications

Doxylamine is a member of the ethanolamine class of antihistamines and has anti-allergy power superior to almost every other antihistamine on the market, with the exception of diphenhydramine (Benadryl).^[2] It is also the most effective over-the-counter sedative available in the United States,^[2] and is more sedating than some prescription hypnotics. One study found that doxylamine succinate is possibly more effective than the barbiturate phenobarbital for use as a sedative.^[2]

The dosage required to induce hypnosis (sleep) can be as low as 6.25 mg, but is usually effective in dosages of up to 25 mg. Higher doses are not recommended by the United States Food and Drug Administration, although single dosage recommendations of up to 50 mg are common in some countries, including Australia, where it is marketed under the names Restavit and Dozile.

Metabolites

The two main metabolites are desmethyldoxylamine and didesmethyldoxylamine.

Formulations

• It is the sedating ingredient of NyQuil.
• In Commonwealth countries, such as Australia, Canada, South Africa and the United Kingdom, doxylamine is available prepared with paracetamol (acetaminophen) and codeine under the brand name Dolased, Syndol, or Mersyndol, as treatment for tension headache and other types of pain.
• Doxylamine succinate is used in general over-the-counter sleep-aids branded as Somnil, Dozile, Donormyl, Dormidina, Restavit and Unisom-2.
• In the United States doxylamine succinate is the active ingredient in the over-the-counter sleep-aid tablets branded as Unisom; however, according to the manufacturer's website, the gel-cap form contains diphenhydramine hydrochloride instead.
• It is also available in combination with vitamin B₆ and folic acid under the brand name Evanorm (marketed by Ion Healthcare).
• In Canada, doxylamine succinate and pyridoxine (vitamin B6) are the ingredients of Diclectin, which is used to prevent morning sickness.

Side effects

Doxylamine succinate is a potent anticholinergic and has a side-effect profile common to such drugs, including dry mouth, ataxia, urinary retention, and drowsiness.

Toxicity

Doxylamine succinate is generally safe for administration to healthy adults. Typical preparations that contain doxylamine range from 6.25 mg to 25.0 mg. The LD50 is estimated to be 50–500 mg/kg in humans.^[3] Symptoms of overdose may include dry mouth, dilated pupils, insomnia, euphoria, hallucinations, seizures, rhabdomyolysis, and death.^[4] Fatalities, while rare, have been recorded.^[5] Rarely, an overdose results in rhabdomyolysis and acute renal failure.^[6]

References

1. ^ http://www3.interscience.wiley.com/journal/98016819/abstract
2. ^ ^{a b c} DrugBank: DB00366 (Doxylamine)
3. ^ http://hazard.com/msds/mf/baker/baker/files/d8882.htm
4. ^ Syed, Husnain; Sumit Som, Nazia Khan, Wael Faltas (17 March 2009). "Doxylamine toxicity: seizure, rhabdomyolysis and false positive urine drug screen for methadone". BMJ Case Reports (BMJ Group) 2003 (90): 845. doi:10.1136/bcr.09.2008.0879. http://casereports.bmj.com/cgi/content/abstract/2009/mar08_1/bcr0920080879. Retrieved 29 November 2009. 
5. ^ http://www.medsafe.govt.nz/Profs/DataSheet/d/Dozilecap.htm
6. ^ Leybishkis B, B; Fasseas P; Ryan KF. (July 2001). "Doxylamine overdose as a potential cause of rhabdomyolysis". American journal of the medical sciences (Lippincott Williams & Wilkins) 322 (1): 48–9. PMID 11465247. 

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