Pax is diazepam — a benzodiazepine, in 5 mg and 10 mg tablets. It is used for short-term severe anxiety, muscle spasm, alcohol withdrawal and some seizures. It works quickly and well, and dependence develops within weeks, which is why it is prescribed in days rather than months.
What is Pax?
The South African Medicine Price Registry lists Pax as a Schedule 5 tablet containing diazepam 10 mg, and Pax-5 containing diazepam 5 mg.
Be careful with the name. Several unrelated products contain “pax”: Zopax is alprazolam, Paxadorm nitrazepam, Nitepax a cough syrup, Relpax a migraine medicine. Check your own pack.
Diazepam is a benzodiazepine. It enhances the effect of GABA, the brain’s main inhibitory signal — the chemical that damps down neuronal activity. Boosting it produces the four effects diazepam is used for: reduced anxiety, muscle relaxation, sedation, and raised seizure threshold.
Two properties define diazepam. It is long-acting — diazepam and its active breakdown products stay in the body for days, which is why a single dose can leave you drowsy the next day and why it accumulates with repeated dosing, particularly in older people. And it acts fast, with peak effect within an hour. Fast onset is what makes a medicine feel rewarding, and part of why benzodiazepines are misused.
The dependence problem is the central fact about this medicine, and it is not a moral matter. The brain adapts to sustained GABA enhancement within two to four weeks of regular use. Once adapted, stopping produces rebound anxiety worse than the original, insomnia, tremor, sweating, and — after prolonged high-dose use — seizures. Withdrawal from long-term benzodiazepines is genuinely difficult, sometimes taking months of gradual reduction.
This is why prescribing guidance worldwide limits benzodiazepines to two to four weeks, and why a prescription that keeps being repeated deserves a conversation rather than another repeat.
None of that means it is a bad medicine. For severe acute anxiety, alcohol withdrawal, muscle spasm or status epilepticus, diazepam is genuinely excellent. The problem is duration, not the drug.
What is Pax commonly used for?
- Severe short-term anxiety, where it is used for days, not months, usually while another treatment takes effect.
- Acute panic, in the short term.
- Muscle spasm — from back injury, whiplash, or neurological conditions. Diazepam is one of the better muscle relaxants available.
- Alcohol withdrawal, where it prevents seizures and delirium tremens. This is one of its most important uses, and alcohol withdrawal should be medically supervised because it can kill.
- Seizures and status epilepticus, usually as an injection or rectal preparation.
- Sedation before a procedure, and short-term severe insomnia, though shorter-acting alternatives are usually preferred.
- Vertigo, in the acute phase.
Two points that change how well treatment goes.
It treats the symptom, not the cause. For anxiety, cognitive behavioural therapy and SSRIs are the treatments that actually work long term. Diazepam quietens anxiety while those are arranged or take effect. Used alone for months, it stops working, becomes hard to stop, and leaves the underlying problem untouched.
For back pain and muscle spasm, staying active does more than resting. Diazepam can make movement possible; it is not a reason to stay in bed, and prolonged rest makes back pain worse.
How Pax fits into this medicine category
| Group | Examples | Notes |
|---|---|---|
| Benzodiazepines | Diazepam (Pax), alprazolam, lorazepam, clonazepam | Fast; effective; dependence within weeks |
| Z-drugs | Zolpidem (Nurika) | Short-term insomnia; similar dependence risk |
| SSRIs | Sertraline, escitalopram | First-line for anxiety disorders; take weeks |
| SNRIs | Venlafaxine, duloxetine | Anxiety and depression |
| Tricyclics | Amitriptyline (Trepiline) | Sedating; nerve pain at low dose |
| Gabapentinoids | Pregabalin | Anxiety and nerve pain; also causes dependence |
| Beta blockers | Propranolol | Physical symptoms of anxiety only |
| Antihistamines | Hydroxyzine | Short-term anxiety; no dependence |
The most useful thing on this table is the third row. For generalised anxiety, panic disorder or social anxiety, an SSRI plus therapy is the treatment. It takes four to six weeks, which is exactly why a short benzodiazepine course sometimes bridges the gap — as a bridge, not a destination.
See the mental health and neurology medicines hub.
What to check before using Pax
The most dangerous interaction is with opioids. Combining a benzodiazepine with codeine, tramadol, morphine or methadone significantly raises the risk of fatally slowed breathing, and this combination is behind a large share of overdose deaths. If you take both, that must be a deliberate decision by your prescriber.
Also tell your doctor if you:
- Take other sedatives — sleeping tablets, sedating antihistamines, pregabalin or gabapentin — or drink alcohol. The effects are additive and alcohol plus diazepam is genuinely dangerous.
- Have breathing problems, COPD, or sleep apnoea.
- Have liver disease or kidney disease.
- Have myasthenia gravis, where it is contraindicated.
- Have a history of substance or alcohol dependence.
- Have depression or thoughts of self-harm. Benzodiazepines can worsen depression.
- Are elderly. Diazepam accumulates, and confusion, falls and fractures are substantially more likely. It appears on every list of medicines to avoid in older people.
- Are pregnant, planning pregnancy or breastfeeding.
- Have glaucoma.
Practical points:
- Do not drive until you know how it affects you. Next-day impairment is real and common with diazepam because of its long half-life.
- Avoid alcohol entirely.
- Take the lowest dose for the shortest time.
- Do not stop suddenly after more than a couple of weeks. Reduce gradually with your doctor.
- Do not share it. It is Schedule 5, and sharing benzodiazepines is both illegal and dangerous.
- Store it securely. Benzodiazepines are diverted and misused.
Possible cautions and when to ask a pharmacist or doctor
Common effects: drowsiness, unsteadiness, muscle weakness, confusion, slurred speech, blurred vision, headache and memory gaps.
Get emergency help for:
- Slow or shallow breathing, or difficulty waking someone — particularly if an opioid or alcohol is also involved.
- Severe confusion or unresponsiveness.
- A seizure, particularly if the medicine has been stopped suddenly.
- Swelling of the face, lips or tongue, or difficulty breathing.
- Thoughts of harming yourself. Contact a doctor, an emergency department, or the South African Depression and Anxiety Group.
Seek prompt advice for:
- Paradoxical reactions — agitation, aggression, restlessness or excitement rather than calm. These are uncommon but well recognised, particularly in children and older people, and mean the medicine should be stopped.
- Falls or unsteadiness, especially in an older person.
- Memory problems.
- Worsening low mood.
- Finding yourself needing more, or taking it more often than prescribed. Raise this early rather than late — it is a common experience with this class, not a personal failing, and it is far easier to address before the dose has climbed.
Contact your doctor if:
- You have been taking it more than two to four weeks. This warrants a review and, usually, a plan to reduce.
- You want to stop — so it can be tapered. Stopping abruptly after regular use can cause severe withdrawal and seizures.
- Anxiety is not improving, or is the main problem — in which case an SSRI and therapy are the treatments, and worth starting.
- You are drinking to cope, or think you may be dependent on alcohol. That is treatable, and diazepam is part of managed withdrawal rather than something to take alongside drinking.
Related medicine guides
Frequently asked questions
What are Pax tablets used for? Short-term severe anxiety, muscle spasm, alcohol withdrawal, some seizures, and sedation before procedures. Pax contains diazepam 10 mg; Pax-5 contains 5 mg.
Is Pax the same as Zopax? No. Pax is diazepam; Zopax is alprazolam. Both are benzodiazepines but they are different medicines at different strengths — check your pack.
Is it addictive? Dependence develops with regular use within about two to four weeks. That is why courses are short and why it is not stopped abruptly.
How long can I take it? Guidance worldwide is two to four weeks at most. Longer use deserves a review and a plan to reduce.
Can I stop suddenly? No, not after more than a couple of weeks. Withdrawal causes rebound anxiety, insomnia, tremor and, after prolonged use, seizures. Reduce gradually with your doctor.
Why am I still drowsy the next day? Diazepam is long-acting — it and its breakdown products stay in the body for days. Next-day impairment is common, and it affects driving.
Can I drink alcohol with it? No. The combination is genuinely dangerous and can slow breathing.
Can I take it with tramadol or codeine? Only if your doctor has decided so deliberately. Benzodiazepines with opioids substantially raise the risk of fatally slowed breathing.
What should I take for anxiety instead? For an anxiety disorder, an SSRI with cognitive behavioural therapy is the treatment that works long term. Diazepam is a bridge, not a destination.