Intravenous Conscious Sedation (aka “IV sedation”) is when a drug, usually of the anti-anxiety variety, is administered into the blood system during dental treatment.
What does it feel like? Will I be asleep?
Some dental practices use terms such as “sleep dentistry” or “twilight sleep” when talking about IV sedation. This is confusing, because it suggests that IV sedation involves being put to sleep. These terms are more descriptive of deep sedation. Deep sedation isn’t commonly used (in the UK at least), and is classified as general anaesthesia (even though sedation occurs on a continuum).
In reality, you remain conscious during conscious IV sedation. You will also be able to understand and respond to requests from your dentist.
However, you may not remember much (or anything at all) about what went on because of two things:
- IV sedation induces a state of deep relaxation and a feeling of not being bothered by what’s going on
- the drugs used for IV sedation produce either partial or full memory loss (amnesia) for the period of time when the drug first kicks in until it wears off. As a result, time will appear to pass very quickly and you will not recall much of what happened. Many people remember nothing at all. So it may, indeed, appear as if you were asleep during the procedure.
First-hand accounts of IV sedation (from our message boards)
“Basically, its just a tiny pinch in the back of the hand and in goes the ‘stuff’. Nothing happens for several seconds and then you begin to feel light-headed (a little drunk) for a few moments, which is not unpleasant. Then instantly several hours have magically passed and everything has been done. Its like the flick of a switch which turns your brain off for an hour or two. You feel fairly dopey and woozy afterwards where you may want to go and sleep it off.”
“Well, I DID IT!!!!!!!! … As I sat in the chair, I could feel my heart racing and remember telling the dentist that I needed to do this… I didn’t feel the IV being inserted, and as he was topping up the sedation level, he gave me the local injections, now this should be freaking me out, but honestly, I only felt a scratch!! and me being needle phobic too! And just to quell any fears about infection being present throughout extraction: The infection I’ve had on and off for months now came back with a vengeance last night, and I NEVER felt it being extracted. Next thing I knew I was in the little recovery room with my partner.”
“I had IV sedation back in June, got 2 rotten and abscessed teeth extracted and a filling to a front tooth – remember nothing at all from the IV going in, to being aware I was in my husband’s car asking for some water and telling him how I felt nothing!”
“IV sedation is the best!! I would not hesitate to use it again if I needed to. They numb your hand first, then they put the IV in and before you know it you are off to sleepyland. I really don’t remember too much, just bits and pieces of conversations.”
“I had IV sedation when I got my wisdom teeth surgically removed yesterday. Let me tell you, it was AMAZING. Cannot put it in better words. All I remember is the doctor putting the sedative in the IV, feeling COMPLETELY relaxed, and still in control of everything, and closed my eyes and before I could reach 8 counting backwards, I was peacefully asleep. I woke literally 2 seconds later with no pain at all! I didn’t believe the doctor when he said it was all over.”
Is it still necessary to be numbed with local anaesthetic?
The drugs which are usually used for IV sedation are not painkillers, but anti-anxiety drugs. While they relax you and make you forget what happens, you will still need local anaesthetic.
Will my dentist numb my gums before or after I’m sedated?
If you have a fear of dental injections, you will not be numbed until the IV sedation has fully kicked in. If you have a phobia of needles, you will very probably be relaxed enough not to care by this stage. Your dentist will then wait until the local anaesthetic has taken effect (i. e. until you’re numb) before starting on any procedure.
:?: “But how does the dentist know whether I’m numb?”
:!: “You check the local anaesthetic has worked by asking the patient. Just coz they’re sedated doesn’t mean they can’t answer you… in fact they better be able to answer or they ain’t sedated, they’re anaesthetised! If they’re not numb enough they’ll soon tell you. But they won’t remember telling you of course because of the amnesia effect…” (answer courtesy of Gordon Laurie, BDS)
How is IV sedation given?
“Intravenous” means that the drug is put into a vein. This is done using a cannula (commonly known as a Venflon) – a tiny flexible plastic tube which is placed into one of your veins in the back of your hand or in your arm.
One end sits inside your vein and the other end has a small valve that looks a bit like a tap (the blue bit). The drug is put in through this tap.
The venflon used for IV sedation in dentistry is usually one with a blue tap (like the one on the right, which still has its cap on).
How is the Venflon put in? – Step-by-step explanation
- The dentist or nurse checks your hands and arms to find the best place to put the Venflon. Tell them if you have a preference for where it goes. They might use a stretchy band around your arm to make your veins easier to see.
- Once you’ve decided on a suitable position, you can put local anaesthetic cream on the area. Ametop (scroll down for a first-hand account) is very effective! Local anaesthetic creams should be applied 30-45 minutes beforehand for maximum effect. The area stays numb for 4 to 6 hours. Alternatively, a topical cold spray just before putting in the Venflon can be used. You don’t have to use either of these if you prefer not to.
- The dentist or nurse will wipe off the anaesthetic cream and clean the area.
- A needle which is wrapped up with a tiny soft plastic tube (the Venflon) is inserted into the chosen site. The needle is then slid out, leaving the thin flexible tube in place.
- The Venflon is safely taped into place with a clear non-allergenic plaster or surgical tape, so it can’t accidentally get dislodged.
- Now the drug can be put in through the port (the blue bit).
- The Venflon stays in place from start to finish, so that the drug can be topped up as necessary and so that a reversal drug can be given if necessary (highly unlikely, but it’s reassuring to know that in the event of an emergency, a reversal drug or other emergency could be given).
Throughout the procedure, your pulse and oxygen levels are measured using a pulse oximeter. This gadget clips onto a finger or an earlobe and measures pulse and oxygen saturation. It gives a useful early warning sign if you’re getting too low on oxygen, although if your dentist and the nurses are paying attention they should see it way before the machine does! Blood pressure before and after the procedure should be checked with a blood pressure measuring machine (a tongue-twister called sphygmomanometer, which for obvious reasons is referred to as sphyg).
But I’m terrified of all needles, not just dental injections!
You can get Ametop numbing cream to make the site where the needle goes profoundly numb:
“AMETOP numbing cream. I have a mortal fear of needles, and I find injections unbearable. Every injection I’ve had in my life has been intolerable. However, my dentist managed to get the IV in without me even noticing. I actually just turned round and it was in. The stuff is that good. I did not even feel any pressure. You can get a tube of it from your pharmacist for a few pounds, and it needs to stay in the fridge. If you need proof, buy two tubes, and use one a couple of days before your operation, just to reassure yourself how deeply numb it makes you.” (from our message board)
Ask your dentist or oral surgeon where the venflon will be going beforehand, and try it out! Ametop should be applied 30-45 minutes beforehand. The anaesthetic effect remains for 4 to 6 hours. You will probably need to order Ametop in, as it is not usually in stock in pharmacies. So plan ahead. If you cannot get hold of Ametop, try EMLA cream instead.
You may also be offered inhalation sedation or an oral anti-anxiety medication to enable you to accept the IV sedation.
What drugs are used? Are there different types of IV sedation?
In the UK, the standard technique which is used almost exclusively is a titrated dose of midazolam. ‘Titrated’ means that the drug is given bit by bit until the desired effect is achieved.
1) The Standard Technique: Midazolam
Midazolam is a short acting benzodiazepine (or “benzo” for short), an anti-anxiety sedative. IV-administered midazolam has 3 main effects: it reduces anxiety/relaxes you, it makes you sleepy, and it produces partial or total amnesia (i. e. makes you forget what happened during some or, less frequently, all of the procedure).
The drug is put into the vein at the rate of 1mg per minute. 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.
For some people with special care requirements or extreme needle phobia, where IV sedation isn’t deemed to be suitable, midazolam can also be given in a drink or as a nasal spray. IV sedation is preferable though because you can fine-tune the dose, making it more predictable and controlled.
2) Advanced Techniques
In the UK, it is recommended to only use an advanced technique if “the clinical needs of the person are not suited to sedation using a standard technique” 1. Advanced techniques are usually used in hospital environments, and the sedationist needs to be “suitably experienced”. Drug combinations have less predictable effects than single drugs and the margin of safety is reduced, so their use is uncommon. It is really quite rare that anything other than straightforward midazolam is required.
One drug which is occasionally used as an add-on to midazolam is fentanyl (an opioid).
At first glance, the use of opioids seems appealing, because of the pain-killing factor. In the normal way, this would only come into play for post-treatment pain, because local anaesthetic will take care of any pain during treatment. But where post-op pain is expected, what is often done is give a long-acting local anaesthetic (and over-the-counter painkillers, to be taken before the local anaesthetic wears off).
The addition of an opioid can be useful if the sedation isn’t effective enough (which is more likely if you’ve been using benzodiazepines for many years and have developed a high tolerance to them). In this case, adding an opioid may provide the desired sedation.
As an alternative or in addition to midazolam, propofol may be used. Propofol is classed as a GA drug, because it’s very easy to tip over into GA (general anaesthesia) with it. In the UK, it 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). One advantage of propofol is the very rapid recovery time, less than 5 minutes.
In the U.S., polydrug use is much more common, possibly because IV sedation is taught at a high level. This encourages the use of polypharmacy (multiple drugs). Also, there appears to be a liking for long IV sessions which require the use of polypharmacy. Long IV sessions may be driven by consumer demand, or maybe it’s a training issue. Many IV specialists in the United States are opposed to the use of opioids for sedation, but there is a habit of using them ingrained in most practitioners. However, things appear to be changing as new dentists are coming through.
The general consensus among the experts in the field of dental sedation today is: the fewer medications are used, the safer and more predictable the treatment tends to be. Usually, this means one medication only. Midazolam tends to be the drug of choice. Advanced techniques can, however, be very useful where midazolam has been tried by an experienced practitioner and the desired effect couldn’t be achieved.
Is it safe? Are there any contraindications?
IV sedation is extremely safe when carried out under the supervision of a specially-trained dentist. In a recent review of studies looking at death rates related to dental anaesthesia, the studies looking at IV sedation reported a death rate of precisely zero 2.
The current biggest contraindications are overweight patients with a high BMI (a common cut-off is BMI>35), and patients with hypertension, diastolic pressure over 100.
Other contraindications include
- known allergy to benzodiazepines
- alcohol intoxication
- CNS depression, and
- some instances of glaucoma.
Cautions (relative contraindications) include psychosis, impaired lung or kidney or liver function, advanced age, and sleep apnea. Many people who have sleep apnea haven’t been officially diagnosed – if you are overweight and you snore, do mention this.
Heart disease is generally not a contraindication.
If you have been taking benzodiazepines for many years, your tolerance may be high – so let your dentist know that you’ve been taking them!
The Dental Sedation Teachers Group uses the following classification for making the decision if and where conscious sedation should be provided:
- I – Normal, healthy patient
- II – A Patient with mild systemic disease, e.g. well controlled diabetes or epilepsy, mild asthma
- III – A patient with severe systemic disease limiting activity but not incapacitating, e. g. epilepsy with frequent fitting, uncontrolled high blood pressure, recent heart attack
- IV – A patient (usually hospitalised or bedridden) with incapacitating disease that is a constant threat to life
- V – A patient who is expected to die within 24 hours with or without treatment
source: American Society of Anaesthesiology Classification of Physical Status (ASA)
If you are in category I or II, then you can normally be treated in a general practice.
If you are in category III, it is best to be treated in an environment where more experienced support is available (a hospital-based clinic or a sedation clinic where medical support is available).
What are the main advantages of IV sedation?
- IV sedation tends to be the method of choice if you don’t want to be aware of the procedure – you “don’t want to know”. The alternative in the U.S. is oral sedation using Halcion, but oral sedation is not as reliably effective as IV sedation.
- The onset of action is very rapid, and drug dosage and level of sedation can be tailored to meet the individual’s needs. This is a huge advantage compared to oral sedation, where the effects can be very unreliable. IV sedation, on the other hand, is both highly effective and highly reliable.
- The maximum level of sedation which can be reached with IV is deeper than with oral or inhalation sedation.
- Benzodiazepines produce amnesia for the procedure.
- The gag reflex is hugely diminished – people receiving IV sedation rarely experience difficulties with gagging. However, if minimizing a severe gag reflex is the main objective, inhalation sedation is usually tried first. Only if that fails to diminish the gag reflex should IV sedation be used for this purpose.
- Unlike General Anaesthesia or Deep Sedation, conscious IV sedation doesn’t really introduce any compromises per se in terms of carrying out the actual procedures, because people are conscious and they can cooperate with instructions, and there is no airway tube involved.
Are there any disadvantages?
- It is possible to experience complications at the site where the needle entered, for example hematoma (a localized swelling filled with blood).
- While IV sedation is desired precisely because of the amnesia effect (i. e. forgetting what happened while under the influence of the drug/s), there can be a downside to this: if you can’t remember that the procedure wasn’t uncomfortable or threatening, you cannot unlearn your fears. However, it depends on the precise nature of your phobia and the underlying causes to which extent this may be a problem. Some people would voice a concern that some patients can’t be “weaned off” IV sedation, as dental anxiety tends to returns to baseline levels. As a result, people who rely on IV sedation may be less likely to seek regular dental care. Other people would argue that this is not a concern if IV sedation is readily available to people.
- Some dentists may resort to IV sedation too quickly. Sedation should not be used as a substitute for TLC and behavioural techniques, but as an additional tool if these alone don’t work, or if it is a potentially traumatic procedure. You should want sedation, rather than feeling forced into it because your dentist is unwilling to explore other ways of helping you.
- Recovery from IV administered drugs is not complete at the end of dental treatment. You need to be escorted by a responsible adult.
- Cost is another disadvantage – IV sedation is more expensive than other sedation options.
Can I take valium tablets or other benzodiazepines beforehand?
Yes. You must let your dentist know about it though (unless your dentist has prescribed them and knows already). It’s best to do this before you turn up on the day, because you’re likely to forget to mention it.
What about eating and drinking before standard (midazolam) IV sedation?
Many clinicians nowadays are happy with you eating and drinking on the day of your appointment, as long as you avoid alcoholic drinks and large meals. Some dentists like to have people have a light meal about an hour before they come in. However, if there is any chance that oversedation (and the loss of protective airway reflexes) might occur, then fasting is usually advised. This is more likely if an advanced technique is used. There may also be risk factors that are particular to your situation, so follow your dentist’s advice on fasting.
After IV Sedation:
- Have your escort take you home immediately (no shopping trips please) and rest for the remainder of the day.
- Have an adult stay with you until you’re fully alert, but at least for 8 hours.
- Don’t perform any strenuous or hazardous activities and don’t drive a motor vehicle for the rest of the day.
- Don’t drink alcohol or take medications for the rest of the day unless you’ve contacted your dentist first.
- Take medications as directed by your dentist.
- If you have any unusual problems, call your dentist.
Conscious Sedation in Dentistry – Dental Clinical Guidance (June 2017). Scottish Dental Clinical Effectiveness Programme.
Standards for Conscious Sedation in the Provision of Dental Care (2015). The dental faculties of the royal colleges of surgeons and the Royal College of Anaesthetists.
Terrified of twilight sedation: Answers to common concerns about IV sedation (from our message boards).
The information on this page has been produced by Dental Fear Central with the help and guidance of Gordon Laurie, a specialist in Special Care Dentistry. Last reviewed by Gordon Laurie BDS on December 14, 2018. We welcome your feedback on our information resources.