DENTAL IV SEDATION

[drsushant]

The most commonly used drugs for IV sedation are benzodiazepines, or “benzos” for short. These are anti-anxiety sedative drugs. In the UK, a benzodiazepine is almost always the only drug used for IV sedation (although I have heard of fentanyl being used as well). However, the situation is different in the U.S. First of all, regardless of location, what are the drugs which can be used for IV sedation?

1) Anti-anxiety sedatives (benzodiazepines): Midazolam and Diazepam

Mostly the drug used for IV sedation is a short acting benzodiazepine, or “benzo” for short. This is an anti-anxiety sedative. IV administered benzos have 3 main effects: they reduce anxiety/relax you, they make you sleepy, and they produce partial or total amnesia (i. e. make you forget what happened during some or, less frequently, all of the procedure). Total amnesia is more common with midazolam compared to diazepam.

By far the most commonly used drug for IV sedation is Midazolam, but occasionally Diazepam can be used.

Midazolam is the first choice because of its relatively short duration of action (meaning that it’ll be out of your system faster). Valium is (marginally) cheaper but longer acting and a bit “harder” on the veins, so you may feel a burning sensation on your arm/hand when the drug first enters. Local anaesthetic solution can be mixed in with Diazepam to make things more comfortable. The latest IV Diazepam is an emulsion which is claimed to be easier on the veins.

The drug is put into the vein at the rate of 1mg per minute for Diazepam or 1 mg every 2 minutes (followed by an extra 2 minutes to evaluate the effect) for Midazolam (because Midazolam is stronger in terms of the dose needed to achieve sedation). Because there are differences between individuals in how much of the drug you need to be sedated, your response to the drug is monitored. Once the desired level of sedation is achieved, the drug is stopped.

The Venflon is left in place during the procedure so that the sedation can either be topped up or so that the reversal agent for benzos (Flumazenil) can be put in in the unlikely event of an emergency.

2) Opioids

Opioids (strong pain-killers) can be used as an add-on to either benzodiazepines or barbiturates.

At first glance, the use of opioids seems appealing, because of the pain-killing factor. In reality, this usually only comes into play for post-treatment pain, because local anaesthesia will take care of any pain during treatment. However, should the local anesthetic effect begin to lessen, an opioid will help to alter the experience of pain.

What is often done instead is give a long-acting local anaesthetic where post-op pain is expected. When you take opioids, even terrible pain becomes tolerable – you can still feel the pain, but somehow you don’t care. Also, where barbiturates are used (see below), an opioid must be added to counteract their pain-threshold-lowering properties.

The addition of an opioid may also be desirable if a benzo has been administered to its maximum recommended dose yet the patient remains unsedated (which is more likely if you’ve been using benzodiazepines for years and have become tolerant to them). In this case, adding an opioid may provide the desired sedation. Alternatively, propofol (see below) may be used.

Opioids which may be used for IV sedation include:

Meperidine (Demerol)
Morphine
Butorphanol (Stadol)
Nalbuphine (Nubain)
Fentanyl (Sublimaze)
Pentazocine (Talwin)
3) Barbiturates

Barbiturates (sleep-inducing drugs) are not used for conscious sedation in the U.K., and have gone out of fashion in the U.S. The only barbiturate which is still occasionally used is called Pentobarbital Sodium (tradename: Nembutal).

In the absence of a trained anesthesiologist, barbiturates are pretty dangerous to use, for a number of reasons: it’s very easy to have the patient slip into general anaesthesia by mistake, where breathing and heart rate are dangerously lowered and coma and death can follow. Worse still, unlike for benzos, there’s no reversal agent. Barbiturates have only one advantage over benzos, and that is that they can be used to provide very long periods of conscious sedation. If pentobarbital is used, it’s in combination with opioids (see above), because barbiturates have the effect of lowering a person’s pain threshold.

4) Propofol

Some anaesthetists use Propofol instead of benzodiazepines. The advantage of this is the very rapid recovery time, less than 5 minutes. The drug must be continuously administered, so the drug is pumped in using an electric infusion pump, the dose rate is set by the anaesthetist. Propofol is not a common sedative agent because it’s very easy to tip over into GA (General Anaesthesia) with it, where reflexes such as breathing are lost. It can be useful you have developed a high tolerance to benzodiazepines because you’ve been hitting them hard for years. Propofol is classed as a GA drug and in the U.K. can only be administered in a hospital setting (although a few private dental clinics meet the standard of a hospital setting, and offer it as well).