Sedatives- Hypnotics

Insomnia is defined as the inability to fall asleep or to go back to sleep once one has awoken. Elderly pts may fall asleep very easily but wake up at 2 or 3 am and not be able to go back to sleep. In dentistry, you’ll encounter pts who may have trouble sleeping due to their anxiety about upcoming treatment. This requires an anti-anxiety agent, although there is a fuzzy line between anti-anxiety and anti-insomnia drugs- in any case, the dentist will most likely not be the one writing prescriptions for anti-insomniac drugs.

We deal with circadian rhythms, often times there are shifts in this cycle as in night workers and those with jet-lag.


Another rare, but real, syndrome is narcolepsy. This is when a person will enter a sudden deep sleep, and is hard to arouse. There are specific drugs that we will later allude to. Drugs that promote sleep are hypnotics, although most pharmacologists refer to sedatives/hypnotics together. Conscious sedation is not from hypnotic drugs, this is different from using a hypnotic to produce sleep in an insomniac.


“Therapeutic Overview”

The drugs used to treat insomnia can include drugs that suppress the CNS. The Benzodiazepines are the premier agents, and were developed in the 1970s. The barbiturates used to have a premier role as sedatives (Secobarbital, Pentobarbital) and were prescribed by an MD for insomniacs. But because they are very addictive, even short term use is now obsolete because the benzodiazepines have a much better therapeutic index, without the side effects of the barbiturates. However, there is still a use for barbiturates in dentistry, particularly for intravenous anesthesia. The antihistamines, particularly diphenhydramine, are contained in many of the otc sleep-aids. If a pt takes this they will have anticholinergic effects (severe xerostomia, etc.) along with sleepiness. Agents like chloral hydrate and paraldehyde are obsolete. Deaths have occurred in the dental office from injudicious use of chloral hydrate, it is a powerful CNS depressant with a very narrow therapeutic index. All of these drugs except diphenhydramine are CNS depressants, so the risk of overdose and coma/ respiratory suppression are very real.


The anti-hypersomnia drugs combat excess sleep and narcolepsy. These include CNS stimulants, dextroamphetamine, pemoline, and methylphenidate (Ritalin, to be used for Attention Deficit Disorder- ADD).



The phrase “benzodiazepine” is important, because all of the chemicals belonging to this class have the same basic structure, but vary in their potency, onset of action, and duration of action; this is the only way that we can distinguish between them because they have the same mechanism. Triazolam was the number 1 prescribed drug in the 1970s for insomnia, the brand name was Halcion. This drug is now obsolete because it can cause excitation, suicidal and homicidal tendencies, paradoxically. You will still find some pts taking Halcion though, it’s still available.


Pentobarbital is a different structure, there is a narrow therapeutic index (t.i.) and a high risk of dependence developing for the barbiturates. Pentobarbital is the sleeping pill most effective for committing suicide, because it can cause respiratory depression and cardiovascular collapse when overdosed… it is almost impossible to commit suicide taking a benzodiazepine.



All of these drugs have a quick onset of action. Obviously if you’re trying to fall asleep you don’t want to lie there for a long time. The CNS stimulants have significant abuse potentials, depending on which one we’re talking about. The amphetamines are schedule II drugs.



“I’m only going to point out the drugs that are important to you.” They’re all effective via the oral route. Triazolam (Halcion) was number 1 for many years, has a short ½ life. Most people wake up the next morning without any drug hangover. Flurazepam has a long ½ life, causes daytime drowsiness with prolonged sedation and “drug hangover.” Barbiturates have a long ½ life, same problems- daytime drowsiness, etc. With Diphenhydramine (Benadryl derivatives), pts will get xerostomia along with drowsiness. If you prescribe this to achieve xerostomia, don’t be surprised when the pt falls asleep in the chair.



Zolpedem (Ambien) is now the number 1 prescribed sedative in the world. Zaleplon (Sonata) is identical to Ambien, trying to get into the market. Diphenhydramine (Benedryl) is found in otc sleep aids.



Pts given a prescription for short-term management of insomnia (ideally 10-14 days) does nothing to cure the cause, only manages the problem. With the CNS stimulants, (amphetamine class) pts are irritable and get tachycardia, etc. Ritalin (methylphenidate) is a sympathomimetic, so parents must be careful- this is why treatment with Ritalin is controversial because of the number of kids being diagnosed with ADD.



The drug names that we should pay the most attention to include: Dalmane (flurazepam), Halcion (triazolam), Seconal (secobarbital), Ambien (zolpidem)

Category: Pharmacology Notes