How does this medication work? What will it do for me?

Chloral hydrate belongs to the group of medications known as sedatives and hypnotics. It promotes sedation and sleep by acting on certain areas of the brain. Chloral hydrate is used to manage short-term sleeping problems and is used before surgery or other procedures to reduce anxiety or to produce sedation or sleep.

Your doctor may have suggested this medication for conditions other than those listed in these drug information articles. As well, some forms of this medication may not be used for all of the conditions discussed here. If you have not discussed this with your doctor or are not sure why you are taking this medication, speak to your doctor. Do not stop taking this medication without consulting your doctor.

Do not give this medication to anyone else, even if they have the same symptoms as you do. It can be harmful for people to take this medication if their doctor has not prescribed it.

What form(s) does this medication come in?


Each 5 mL of orange-flavoured syrup contains 500 mg of chloral hydrate USP. Nonmedicinal ingredients: citric acid, sucrose, D&C Yellow No. 10 dye, FD&C Red No. 40 dye, glycerin, methylparaben, orange extract (natural), propylene glycol, purified water, sodium benzoate, sodium citrate, and sucrose.


Ask your pharmacist or doctor for details.

How should I use this medication?

When used as a sleeping aid, the recommended adult dose of chloral hydrate is 500 mg to 1,000 mg taken 15 to 30 minutes before bedtime. Drowsiness usually occurs within 10 to 15 minutes, and sleep within 30 to 60 minutes after taking chloral hydrate. The starting dose may be lower for seniors (e.g., 250 mg taken 15 to 30 minutes before bedtime).

When used as a sedative, the recommended adult dose of chloral hydrate is 250 mg taken 3 times daily after meals to a maximum of 2,000 mg per day.

When used before surgery or medical procedures, the recommended adult dose of chloral hydrate is 500 mg to 1,000 mg taken 30 minutes before the procedure.

For use by children, the recommended dosage of chloral hydrate is based on body weight. As a sleeping aid, the recommended dose of chloral hydrate is 50 mg per kilogram of body weight (to a maximum of 1,000 mg per dose) at bedtime. As a sedative, the dose of chloral hydrate is 25 mg per kilogram of body weight per day in 3 to 4 divided doses taken after meals (to a maximum of 500 mg per dose). When used before surgery or medical procedures, the recommended dose of chloral hydrate is 25 mg per kilogram of body weight to 50 mg per kilogram of body weight 30 minutes before the procedure (to a maximum of 1,000 mg per dose). Drowsiness usually occurs within 15 minutes, and sleep by 40 minutes after taking chloral hydrate. Most children are fully awake within 2 hours.

Chloral hydrate should be taken with a full glass of fluid to reduce stomach side effects. It can also be mixed in other liquids such as fruit juice or ginger ale. This medication is normally only used for short periods of time as it can become habit-forming and lose its effectiveness.

Many things can affect the dose of a medication that a person needs, such as body weight, other medical conditions, and other medications.If your doctor has recommended a dose different from the ones listed here, do not change the way that you are taking the medication without consulting your doctor.

It is important to use this medication exactly as prescribed by your doctor. If you miss a dose of this medication, skip the missed dose and continue with your regular schedule. Do not take a double dose to make up for a missed one. If you are not sure what to do after missing a dose, contact your doctor or pharmacist for advice.

Store this medication at room temperature away from excess heat, keep it from freezing, and keep it out of the reach of children.

Do not dispose of medications in wastewater (e.g. down the sink or in the toilet) or in household garbage. Ask your pharmacist how to dispose of medications that are no longer needed or have expired.

Who should NOT take this medication?

Chloral hydrate should not used by anyone who:

  • is allergic to chloral hydrate or to any of the ingredients of the medication
  • has severe reduction in kidney or liver function

What side effects are possible with this medication?

Many medications can cause side effects. A side effect is an unwanted response to a medication when it is taken in normal doses. Side effects can be mild or severe, temporary or permanent. The side effects listed below are not experienced by everyone who takes this medication. If you are concerned about side effects, discuss the risks and benefits of this medication with your doctor.

The following side effects have been reported by at least 1% of people taking this medication. Many of these side effects can be managed, and some may go away on their own over time.

Contact your doctor if you experience these side effects and they are severe or bothersome. Your pharmacist may be able to advise you on managing side effects.

  • diarrhea
  • dizziness or lightheadedness
  • drowsiness
  • flatulence or gas
  • "hangover" effect
  • headache
  • nausea or vomiting
  • stomach pain
  • taste disturbances
  • unsteadiness

Although most of the side effects listed below don't happen very often, they could lead to serious problems if you do not check with your doctor or seek medical attention.

Check with your doctor as soon as possible if any of the following side effects occur:

  • abnormal heart rhythms
  • confusion
  • disorientation
  • eye infection
  • hallucinations
  • paranoia
  • skin rash

Stop taking the medication and seek immediate medical attention if any of the following occur:

  • signs of an allergic reaction (shortness of breath or difficulty breathing; hives; swelling of the eyes, mouth, lips, or throat)

Some people may experience side effects other than those listed. Check with your doctor if you notice any symptom that worries you while you are taking this medication.

Are there any other precautions or warnings for this medication?

Before you begin using a medication, be sure to inform your doctor of any medical conditions or allergies you may have, any medications you are taking, whether you are pregnant or breast-feeding, and any other significant facts about your health. These factors may affect how you should use this medication.

Drowsiness/reduced alertness: Chloral hydrate may cause dizziness or drowsiness. Do not engage in activities requiring mental alertness, such as driving or operating machinery, after you take this medication.

Drug dependence and withdrawal: Chloral hydrate can be habit-forming and should therefore only be used for short periods of time. If you have been taking this medication for a long time, discuss with your doctor how to stop taking this medication. Do not stop taking it suddenly without first talking to your doctor.

Gastrointestinal problems: Chloral hydrate may worsen esophagitis (inflammation of the esophagus), gastritis (inflammation of the stomach), and intestinal ulcers. Chloral hydrate is not recommended for use by people with these conditions.

Other medical conditions: People with depression, who are suicidal, or who have a history of drug or alcohol dependence should discuss with their doctor how this medication may affect their medical condition, how their medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.

Severe heart disease: Chloral hydrate should not be used by people with severe heart disease due to the risk of unusual heart rhythms and low blood pressure.

Pregnancy: This medication should not be used during pregnancy unless the benefits outweigh the risks. If you become pregnant while taking this medication, contact your doctor immediately.

Breast-feeding: This medication passes into breast milk. If you are a breast-feeding mother and are taking chloral hydrate, it may affect your baby. Talk to your doctor about whether you should continue breast-feeding.

Children: Children may be more at risk for experiencing breathing-related side effects from chloral hydrate. Children with enlarged adenoids and obstructive sleep apnea, and those with obstructive sleep apnea due to other causes, may experience potentially life-threatening breathing problems. Discuss the risk and benefits with your doctor.

Seniors: Lower doses may be needed for seniors with reduced liver or kidney function, and for seniors who are debilitated.

What other drugs could interact with this medication?

There may be an interaction between chloral hydrate and any of the following:

  • alcohol
  • antipsychotic medications (e.g., haloperidol, loxapine, risperidone)
  • barbiturates (e.g., pentobarbital, phenobarbital, secobarbital)
  • dimenhydrinate
  • diphenhydramine
  • furosemide (intavenous)
  • narcotic pain medications (e.g., codeine, hydromorphone, meperidine, methadone, morphine, oxycodone)
  • other sleeping aids or tranquilizers (e.g., alprazolam, clonazepam, diazepam, lorazepam, midazolam, oxazepam, triazolam)
  • tricyclic antidepressants (e.g., amitriptyline, desipramine, impiramine, nortriptyline)
  • warfarin

If you are taking any of these medications, speak with your doctor or pharmacist. Depending on your specific circumstances, your doctor may want you to:

  • stop taking one of the medications,
  • change one of the medications to another,
  • change how you are taking one or both of the medications, or
  • leave everything as is.

An interaction between two medications does not always mean that you must stop taking one of them. Speak to your doctor about how any drug interactions are being managed or should be managed.

Medications other than those listed above may interact with this medication. Tell your doctor or prescriber about all prescription, over-the-counter (non-prescription), and herbal medications you are taking. Also tell them about any supplements you take. Since caffeine, alcohol, the nicotine from cigarettes, or street drugs can affect the action of many medications, you should let your prescriber know if you use them.