Trial of Oral Ketamine

Trial of Oral Ketamine

Patient Information

Chronic Pain Service

• Author ID:           SD / LB
• Leaflet Ref:         Pain 020
• Version:              10
• Leaflet title:         Trail of Oral Ketamine
• Date Produced:   July 2025
• Expiry Date:        July 2027

What is Ketamine?

Ketamine is a liquid drug that has been widely used as an anaesthetic agent for many years. It is only in more recent time that it has been used purely in the management of pain. 

How does it work?

Research has not yet determined how the drug acts although several theories have been suggested. 

What does a trial of oral ketamine involve?

You will come in for the morning to the Day Surgery Unit at Leigh Infirmary. You will not go to the operating theatre. You will stay on the ward where you will get the drug. A small dose of the drug will be given to you by mouth. 

We would ask you to remain seated/lying down for at least an hour after the drug has been given to make sure that you are not lightheaded when you get up.  The drug works quickly, and we will know whether it helps your pain by the end of the morning. 

The medicine should be taken sublingually (that is to say - under the tongue). Please try not to swallow but hold the medicine under your tongue until it is absorbed. 

What happens after the trial? 

If you have found the medicine useful for your pain, the doctor will arrange for you to be taught how to draw it up properly so that you can give it to yourself safely. 

You will be reviewed every 6 months by the pain nurse. Once a year this must be a face-to-face appointment. 

You will need a blood test every 12 months to check your liver and kidney function. The pain team will arrange this for you if they need to be done. 

Benefits

Unfortunately, we cannot guarantee you will gain benefit from this drug. 

Alternatives

Your pain specialist will have discussed alternatives with you in your consultation; these could be either, different medicines, injections, or physical therapies.  Every patient is unique and therefore specific alternatives cannot be given on an information leaflet as not all treatments are suitable for everyone. 

What are the side effects?

You are advised not to drive or operate machinery (e.g. driving) immediately after taking your medicine. 

Sleepiness may occur for a short period after administering the medicine. 

You may also experience a sensation that everything feels "unreal" or "far away" this will only last for a short while and will soon disappear. 

If you take too much ketamine, you may go to sleep and have unpleasant nightmares and hallucinations. 

You are advised not to drink alcohol when taking this drug as this carries a substantial risk of extreme drowsiness and amnesia.

We do not know what the long-term problems are with using this medicine. Some studies suggest that there may be problems with memory loss or thought processing, but it isn’t known if this is a problem at the doses being used by the clinic. 

It is not licensed for use in chronic pain. There are many drugs that are used but not licensed for many conditions but get used anyway because they work. It is quite often the case that a drug company will not get a license for a drug for a particular condition or age group, as the studies that they need to do to allow the regulatory authorities to provide the necessary license may be too expensive or time consuming to be worth their while. 

Doctors need to treat people, and quite often use unlicensed medicines, because usually there is no alternative. So patients who take unlicensed drugs do so at their own risk, but generally the risk isn’t great in most cases, as the doctor will make a considered judgement as to whether it is reasonable to use the drug in each particular case. 

If you are reading this, then it is likely your doctor has thought it reasonable for you to consider the use of ketamine for your condition.

Please be aware when travelling abroad that the legal status of this drug varies from country to country. We advise that if travelling with Ketamine on your person, that prior to departure from the UK that you have written confirmation from officials from the country to which you are travelling that you are allowed to take Ketamine to that country for your personal use.   

What are patients normally taught to do?

The preparation of your medicine is not a sterile procedure; the syringe you are given is re-usable. You will be taught how to draw up your medicine and place it under your tongue. Most people need to take it about two or three times per day. 

Ketamine can only be obtained through the Hospital Pharmacy. When you need a new prescription, please ring the Pharmacy at least 48 hours before your current supply is finished: 

• Leigh Pharmacy Tel: 01942 264281
• Royal Albert Edward Infirmary Pharmacy Tel: 01942 822491
• Wrightington Pharmacy Tel: 01257 256205. 

Contact information

If you have any questions, please contact the Pain Management Team on:

Telephone: 01942 773099. 

It is very important that you attend any appointments made for you with either, the Doctor; Nurse; Physiotherapist; Occupational therapist or the Psychologist. If you cannot attend, please cancel the appointment, and re-arrange, failure to cancel will result in discharge from the pain service and you will need to be re referred by your GP if you wish to be seen again. 

Please note

In May 2008 a report appeared in the BMJ suggesting that long term use of Ketamine in some patients might cause problems with kidney function and ulcers in the bladder and appearance of blood in the urine and lower abdominal pain. Although most of these patients had been misusing the Ketamine, there were some patients that had been taking it for pain reasons. According to the report, stopping the Ketamine usually improved the situation, but some patients were left with persistent symptoms. The worst affected patients also needed external tubes put into their kidneys and bladder to drain their urine in order to rest the urinary tract. At Leigh we have been using Ketamine since 2000, and have not seen this problem yet (Cottrell, A. M, Athreeres, R., Weinstock, P., Warren, K., Gillatt, D. (2008). Urinary tract disease associated with chronic ketamine use. BMJ 336: 973-973).