Ketamine is an anaesthetic, a painkiller, and — more recently — a treatment for severe depression that has not responded to other medicines. It is also misused recreationally. All three of those are real, and they are very different things.
What is Ketamine S Drug?
Ketamine is a Schedule 6 medicine in South Africa — one of the most tightly controlled categories — supplied as an injection for use in hospitals, clinics and by paramedics. It is not dispensed for use at home.
The “S” in the search term most likely refers to esketamine, sometimes written S-ketamine. Ketamine exists as two mirror-image forms, S and R. Ordinary ketamine contains both; esketamine is the S form isolated, and it is more potent at the main receptor. Esketamine is used as an anaesthetic in some countries and, as a nasal spray, is licensed in the United States and Europe for treatment-resistant depression.
Ketamine works mainly by blocking NMDA receptors, which respond to glutamate — the brain’s main excitatory signal. That produces dissociative anaesthesia: a state in which someone appears disconnected from their surroundings, has profound pain relief and amnesia, but — unusually for an anaesthetic — keeps breathing on their own and maintains blood pressure.
That last property is why ketamine matters. Most anaesthetics suppress breathing and drop blood pressure. Ketamine does neither, which makes it uniquely valuable where those cannot be supported: field medicine, disaster response, poorly resourced settings, and patients who are already unstable. It is on the World Health Organization’s list of essential medicines for exactly this reason.
What is Ketamine S Drug commonly used for?
Anaesthesia and emergency medicine:
- General anaesthesia, particularly for short procedures.
- Procedural sedation — setting fractures, reducing dislocations, wound care.
- Emergency and trauma anaesthesia, including in ambulances and where equipment is limited.
- Anaesthesia in unstable patients, where blood pressure cannot be allowed to fall.
- Anaesthesia in children, where it has a long record.
- Severe asthma, occasionally, since it relaxes airways.
Pain:
- Severe acute pain where opioids alone are insufficient.
- Chronic and neuropathic pain, at low doses under specialist supervision.
- Cancer pain, in palliative care.
- Reducing opioid requirements after surgery.
Mental health:
- Treatment-resistant depression — depression that has not responded to at least two adequate antidepressant trials. This is the use generating the most interest, and the most misunderstanding.
On ketamine for depression, the facts are genuinely striking and genuinely limited. Effects can appear within hours rather than the weeks conventional antidepressants take, which matters enormously in severe depression and in acute suicidal crisis. But the benefit is often short-lived, requiring repeated treatments; long-term safety with repeated dosing is not fully established; and it is delivered in a supervised clinical setting with monitoring, not at home.
Ketamine is not a first-line antidepressant, and it is not a substitute for therapy, conventional medication or addressing what is driving the depression. Where it is used, it is used alongside them.
Ketamine is also misused, and that is a separate matter with real harms. Regular recreational use causes a well-documented ulcerative cystitis — severe bladder damage that can lead to permanent scarring, incontinence and, in serious cases, bladder removal — along with abdominal pain, memory impairment and dependence. Ketamine sold outside medical settings is of unknown identity, dose and purity. Nothing in the medical use of ketamine makes recreational use safe.
How Ketamine S Drug fits into this medicine category
| Group | Examples | Role |
|---|---|---|
| Dissociative anaesthetics | Ketamine, esketamine | Anaesthesia, severe pain, treatment-resistant depression |
| Other anaesthetics | Propofol, thiopental | Anaesthesia; suppress breathing and blood pressure |
| Opioids | Morphine, fentanyl | Severe pain; suppress breathing |
| SSRIs and SNRIs | Fluoxetine, escitalopram | First-line depression treatment; weeks to work |
| Tricyclics | Amitriptyline (Trepiline) | Depression and nerve pain |
| Sleep agents | Zolpidem and related | Short-term insomnia |
See the mental health and neurology medicines hub.
What to check before using Ketamine S Drug
Ketamine is given by clinicians, so these are the things a treating team considers — and the things worth telling them:
- Uncontrolled high blood pressure, recent heart attack, or significant heart disease. Ketamine raises heart rate and blood pressure.
- Raised pressure in the brain or the eye, or recent head injury.
- A history of psychosis or schizophrenia, which ketamine can worsen.
- Liver disease — relevant especially with repeated dosing for depression or pain.
- Bladder or urinary problems, particularly with any prior ketamine exposure.
- Pregnancy or breastfeeding.
- All other medicines, including antidepressants, sedatives, opioids and any recreational substances. Being honest about the last of these matters more than embarrassment about it.
- Recent food and drink, before any procedure.
For depression treatment specifically, expect: treatment in a clinic with monitoring, someone to take you home, no driving for the rest of the day, and a plan that includes ongoing conventional treatment.
Possible cautions and when to ask a pharmacist or doctor
Common effects during and shortly after treatment include dissociation and a dreamlike state, hallucinations, confusion, nausea and vomiting, raised blood pressure and heart rate, dizziness, blurred or double vision, and increased salivation.
Emergence phenomena — vivid dreams, hallucinations or agitation as the drug wears off — are well recognised. They are usually short-lived and are managed by recovering in a calm, quiet setting, and sometimes with a benzodiazepine.
Repeated or prolonged use, medical or otherwise, carries:
- Bladder damage (ulcerative cystitis) — urinary frequency, urgency, pain on passing urine and blood in the urine. This can become permanent. Report urinary symptoms early; it is far more recoverable when caught.
- Liver injury.
- Memory and concentration problems.
- Tolerance and dependence.
Get emergency help for:
- Difficulty breathing, or a severely reduced level of consciousness.
- Chest pain, or a very fast or irregular heartbeat.
- Seizures.
- Severe agitation, confusion or hallucinations that are not settling.
- Inability to pass urine, or severe pain on passing urine with blood.
Contact a doctor if you develop urinary symptoms, abdominal pain, persistent memory problems, or if you are using ketamine outside medical treatment and want help stopping. That last conversation is worth having — bladder damage from ketamine is one of the harms that responds best to stopping early, and clinicians deal with it without judgement.
If you are experiencing severe depression or thoughts of harming yourself, seek help now — from a doctor, a clinic, an emergency department, or a mental health helpline. That is not something to manage alone while researching treatments.
Related medicine guides
Frequently asked questions
What is ketamine used for? Anaesthesia and procedural sedation, severe and chronic pain, and — under specialist supervision — treatment-resistant depression.
What is S-ketamine or esketamine? Ketamine exists as two mirror-image forms. Esketamine is the S form isolated, more potent at the main receptor, and used as a nasal spray for treatment-resistant depression in some countries.
Is ketamine used for depression? Yes, for depression that has not responded to at least two other antidepressants. Effects can appear within hours, but they are often short-lived, and treatment is given in a monitored clinical setting.
Can I get it for depression at home? No. It is Schedule 6 in South Africa and is administered by clinicians with monitoring.
Why is it used in emergencies? Unlike most anaesthetics, it maintains breathing and blood pressure, which makes it valuable where those cannot be supported — trauma, field medicine, unstable patients.
What does recreational use do? Regular use causes severe, sometimes permanent bladder damage, along with abdominal pain, memory problems and dependence. Nothing about its medical use makes that safe.
What should I do about urinary symptoms after using ketamine? See a doctor promptly. Bladder damage is far more recoverable when caught early.
Is it addictive? Tolerance and psychological dependence develop with repeated use, which is one reason medical use is closely supervised.