Oral Sleeping Medicines

Insomnia is a sleep disorder which is characterized by difficulty in falling asleep, staying asleep or waking up too early in the morning. People with insomnia may feel tired or sleepy during daytime and this may impair their performance on daily tasks. Other symptoms that you may have, when suffering from insomnia, may include tension headache, grumpiness, difficulty to concentrate, incoordination of hands and feet and impaired memory.

Many factors can affect your sleep pattern, such as increasing age, undesirable sleeping environment (e.g.excessive noise, light), irregular sleeping hours (e.g. frequent travelling in different time zones, working shifts) and use of products containing caffeine and nicotine (e.g. tea, coffee, smoking cigarettes). In addition, stressful events (e.g. change of job, death in family), medical conditions (e.g. chronic pain and chronic cough), psychiatric conditions (e.g. anxiety, depression) and medications (see table below) may also cause insomnia.

Examples of medications that may lead to insomnia:

Transient or short-term insomnia usually has an underlying cause such as stressful events, changes in sleeping environments, acute medical illnesses and stimulant medications. Thus, identification and removal of the underlying cause is crucial in treating insomnia. In addition, good sleep habits (e.g. avoiding caffeine and alcohol containing drinks before sleep, desirable sleeping environment) are also essential in the treatment of insomnia. Relaxation exercise and avoidance of stimulants (e.g. vigorous exercise and watching television) just before bedtime can also help.

If your insomnia persists for more than four weeks and affects your daily activities and functions, you may need to consult a doctor after trial of the above measures fail. Treatment of insomnia includes cognitive and behavioral treatment and medications. Do not take sleeping medicines without the advice of a healthcare professional.

In Hong Kong, most of the pharmaceutical products available for the treatment of insomnia are prescription only medicines which can only be obtained from a pharmacy with a prescription given by a doctor.

Hypnotics are most commonly used in the treatment of insomnia. However, hypnotics only treat the symptoms of insomnia and do not remove the underlying cause. Thus, they should only be used upon a doctor’s assessment and advice. Due to their side effects, hypnotics should be used at the lowest dose and for the shortest possible duration, which should not exceed four weeks. They are only indicated for short-term relief of insomnia that is severe and disabling.

Common hypnotics used in the treatment of insomnia include benzodiazepines, zopiclone and zolpidem. Other drugs that are used in the treatment of insomnia include antihistamines (e.g. promethazine) and chloral hydrate.

1.Benzodiazepines

Benzodiazepines are the most commonly used hypnotics. They achieve sedative effect by acting on the receptors of gamma-aminobutyric acid (GABA), a neuroinhibitory neurotransmitter.

Benzodiazepines can be classified as long-acting or short-acting, depending on their duration of action. Those commonly used in management of insomnia include :
(a) Long-acting benzodiazepines – diazepam, flurazepam, pinazepam;
(b) Short-acting benzodiazepines – lorazepam, lormetazepam, midazolam, triazolam.

Benzodiazepines shorten the time to fall asleep, decrease awakenings during the night and increase total sleeping time. Short-acting benzodiazepines are often used if you have difficulty in falling asleep as they have a smaller chance of producing ‘hangover feeling’ the next day. Long-acting benzodiazepines are indicated in patients with poor sleep maintenance (e.g. early morning waking), and when an anxiolytic effect is needed during the day. Due to the development of tolerance, dependence and withdrawal symptoms, benzodiazepines are recommended to be taken for the shortest possible duration, which should not exceed 4 weeks.

2.Zopiclone

Zopiclone is a benzodiazepine receptor agonist. It has hypnotic, anxiolytic and amnesic properties due to its high affinity to the GABA receptors in the brain. It is short acting and less likely to cause ‘hangover feeling’ than the short-acting benzodiazepines. However, there is little evidence to show clinical advantages of zopiclone over the benzodiazepines in terms of tolerance, dependence and withdrawal symptoms. Treatment with zopiclone is also not recommended to exceed 4 weeks.

3. Zolpidem

Zolpidem tartrate is reported to have similar sedative properties as the benzodiazepines, but very little anxiolytic and muscle relaxant properties in comparison. Zolpidem has rapid onset and short duration of action but there is little evidence to show any advantage over short-acting benzodiazepines in terms of ‘hangover feeling’, or its potential to induce tolerance or withdrawal symptoms or dependence. Similarly, it is important that treatment should not exceed 4 weeks.

4. Antihistamines

Some sedating antihistamines like promethazine have been used for short-term sedation. They may cause drowsiness on the next day and patients should not drive or operate machinery after taking these medicines. The sedative effect of antihistamines may diminish after a few days of continued treatment. Promethazine may be used in children but the use of promethazine as a hypnotic in children is not justified.

5. Chloral Hydrate

Chloral hydrate is a hypnotic and sedative. It can cause prolonged drowsiness lasting till the next day and patients should not drive or operate machinery after taking this medicine. It has been widely used as a short-term sedative (more commonly used in children) but potential carcinogenicity was once a concern and limited its use. Tolerance to its sedative effect may develop and dependence/withdrawal symptoms may occur.

Uses of benzodiazepines, zopiclone and zolpidem have been commonly associated with the development of tolerance, dependence and withdrawal symptoms. Chloral hydrate may also induce tolerance to its sedative effect.

• Sleeping medicines should preferably be used under medical supervision. They should be used at the lowest effective dose and for a short period of time.
  
  

• Be familiar with the name and dosage of the medicines you are taking. Be cautious about their possible side effects.

• Sleeping medicines may cause drowsiness which may continue into the next day. You should not drive or operate machinery after taking the medicine.
  
  

• Avoid alcoholic drinks.
  
  

• If your insomnia does not improve, discuss with your doctor on other treatment options.
  
  

• There are many factors that may disturb your sleep. The first step in treating insomnia is to find out whether the problem is caused by an underlying medical condition. Treatment of the underlying medical condition can help to improve your insomnia.
  
  

• Develop good sleep habits and discuss with your doctor on some simple methods that can prevent insomnia.
  
  

• If medication is needed, always seek your doctor’s advice on the best treatment option. Your doctor will use the most appropriate medicine(s) after considering your condition and your response to the medicines.
  
  

• Inform your doctor of your medical history and the medicines you are taking because other medicines may interact with your sleeping medication, and some diseases may warrant special precautionary measures.
  
  

• Seek medical advice as soon as possible if you experience any symptoms or side effects that may be related to your sleeping medicines.
  
  

• Do not manage chronic sleep problems by self-medication or health products. Always consult your doctor if you want to take health products or other medications.