Pabrinex Treatment Aftercare Instructions

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Key takeaways

Pabrinex is a high-potency injection of thiamine, riboflavin, pyridoxine, nicotinamide and ascorbic acid, given intravenously or intramuscularly.

It treats Wernicke’s encephalopathy, prevents it during acute alcohol withdrawal, and corrects severe nutritional deficiency.

Wernicke’s dosing is 2 ampoule pairs three times daily for at least 2 days, then 1 pair daily for 3 to 5 days.

Dilute IV Pabrinex in 50 to 100ml of NaCl 0.9% or dextrose 5%, then infuse over at least 30 minutes with resuscitation equipment ready.

Pabau’s clinical record system and digital forms capture every dose, route and monitoring check for audit.

Pabrinex is one of the most closely watched injectable vitamin preparations in UK secondary care. It arrives as two liquid ampoules that you mix in a single syringe. The dilution, the volume and the infusion time all change with the route, and the drug carries a documented anaphylaxis risk.

This guide covers the licensed indications, the dosing regimens in the BNF, and the IV and IM administration steps. It also covers what to do when supply runs short. The downloadable sheet above is the patient-facing half of the job.

What is Pabrinex? Composition and clinical purpose

Pabrinex is a high-potency injection that carries four B vitamins and vitamin C in one preparation:

• Thiamine (vitamin B1): 250mg per ampoule pair. Thiamine drives carbohydrate metabolism and neurological function, and deficiency precipitates Wernicke’s encephalopathy.
• Riboflavin (vitamin B2): 4mg per ampoule pair, a cofactor in oxidative metabolism.
• Pyridoxine (vitamin B6): 50mg per ampoule pair, involved in neurotransmitter synthesis and immune function.
• Nicotinamide (vitamin B3): 160mg per ampoule pair, a component of NAD and critical for cellular energy production.
• Ascorbic acid (vitamin C): 500mg per ampoule pair, an antioxidant and a cofactor in collagen synthesis.

Each unit comes as an ampoule pair. Both ampoules hold liquid, numbered No. 1 and No. 2, and you draw both into the same syringe immediately before use. The license covers intravenous or intramuscular use only, and you never give it orally. Verify every prescribing decision against the current BNF entry for vitamin B substances with ascorbic acid and your trust formulary.

Indications and when to prescribe

Pabrinex covers three broad clinical scenarios, each with its own dosing and urgency:

Wernicke’s encephalopathy is the highest-acuity indication. The triad is ophthalmoplegia, ataxia and acute confusion, and it is a medical emergency. If you suspect Wernicke’s clinically, start Pabrinex without waiting for confirmatory imaging. Subclinical thiamine deficiency is common in alcohol dependence, so treat on a low threshold even when the classic triad is absent.

Alcohol withdrawal prophylaxis is the most frequent use. Thiamine and other B vitamin stores fall quickly during withdrawal because of malnutrition and impaired absorption. Give Pabrinex alongside benzodiazepines and supportive care to prevent seizures and Wernicke’s.

Administration: IV and IM routes

Route selection depends on clinical urgency, patient factors and local protocol. Choose IV for Wernicke’s encephalopathy because onset is faster and bioavailability higher. The two routes then diverge further than the shared ampoule pair suggests.

Intravenous administration

Preparation: Pabrinex IV comes as two liquid ampoules, No. 1 and No. 2. Using an aseptic technique, draw the contents of both ampoules into the same syringe to mix them. Inspect the mixed solution and discard it if it shows discoloration or contains particles.

1. Dilute the mixed ampoule pair in 50 to 100ml of NaCl 0.9% (preferred) or dextrose 5%.
2. Infuse over a minimum of 30 minutes through a peripheral or central line.
3. Never run the infusion faster than 30 minutes, because of the anaphylaxis risk.
4. Flush the line with saline once the infusion is complete.
5. Keep resuscitation equipment at the bedside, including adrenaline, antihistamines and an airway kit.

Record the dilution volume, the diluent, the infusion rate, the start and finish times, and any adverse reaction. Structured clinical forms make those fields mandatory, so none of them ends up buried in free text.

Intramuscular administration

Use IM Pabrinex when IV access is difficult or unavailable. Draw both ampoules into one syringe as above. The IM ampoule pair totals 7ml, a 5ml ampoule plus a 2ml ampoule, and you give it undiluted. Inject high into the gluteal muscle. Avoid the deltoid and vastus lateralis for Pabrinex, because the volume is too large for either site.

IM injection can be painful, so consider local anesthetic infiltration or splitting the dose across two sites when giving more than one pair. Onset is slower than IV, so reserve the route for less urgent situations or where IV is unsuitable.

Cautions, contraindications and safety

Anaphylaxis risk is the most important safety concern. Pabrinex carries a documented risk of anaphylactic reactions, including severe bronchospasm, cardiovascular collapse and angioedema. Reactions are rare, and they have been fatal. Local protocol should require resuscitation equipment at the bedside before every IV infusion, with the clinician present throughout.

The wider pattern of reactions to intravenous vitamin preparations is worth reading before you write that protocol. Our guide to IV therapy complications covers screening, early recognition and the escalation steps for each reaction type.

Absolute contraindications: known hypersensitivity to any component. Thiamine hypersensitivity is very rare, but case reports document it.

Relative cautions: established Wernicke-Korsakoff syndrome, where neurological injury may not fully reverse with treatment. Severe hepatic impairment may alter vitamin metabolism. Renal impairment rarely needs a dose adjustment, but use clinical judgment. Pabrinex has no major documented drug interactions.

Pregnancy and breastfeeding do not contraindicate Pabrinex, and clinicians often use it in pregnant women with alcohol withdrawal or hyperemesis gravidarum. B vitamins are essential micronutrients, so the risks of deficiency usually outweigh the theoretical risks of the preparation.

Monitoring during and after the infusion

Monitoring requirements depend on the indication and the clinical context:

• During IV infusion: watch continuously for anaphylaxis, meaning wheeze, hypotension, urticaria or angioedema. Have adrenaline 0.3 to 0.5mg IM drawn up. Stop the infusion at the first sign.
• Neurological response: in Wernicke’s encephalopathy, eye movements often normalize within 24 to 48 hours when treatment starts early. Ataxia improves more slowly, over days to weeks.
• Alcohol withdrawal: assess seizure risk, consciousness level and autonomic stability. Pabrinex is adjunctive to benzodiazepines and never prevents seizures on its own.
• Serial vitamin levels: not routinely needed. Baseline and follow-up thiamine or B12 levels may help in complex nutritional deficiency cases.

Digital clinical records should capture the indication, the dose, the route, the dilution, the infusion time, any adverse reaction, and the clinician’s assessment of response. That audit trail is what a CQC inspector and a medicolegal review both ask for.

Supply shortages and the alternatives

Pabrinex has been in intermittent short supply since 2021, and the British Society of Gastroenterology shortage guidance sets out what to use instead. None of the alternatives is equivalent:

• Thiamine monohydrate injection: you can give it IV at 100 to 500mg for Wernicke’s encephalopathy, but the license does not cover that route. Check with pharmacy first, and record the unlicensed use in the patient record.
• High-dose oral thiamine: 100 to 500mg three times daily suits alcohol withdrawal prophylaxis or mild deficiency. Onset runs in days rather than hours, and absorption is unreliable in patients with gastric disease.
• Oral B-complex supplements: commercial multivitamins are inadequate for acute deficiency states and should not replace Pabrinex.

Check the NHS England supply chain bulletin and your trust pharmacy for the current shortage status before you prescribe an alternative. Unlicensed use needs explicit consent and a documented rationale.

Side effects and adverse reactions

Most patients tolerate Pabrinex well. Common side effects are mild and pass quickly:

• Local site reactions such as pain, erythema or induration, which are more common with IM.
• Flushing and warmth during IV infusion.
• Mild headache or dizziness.

Serious adverse reactions are rare. Anaphylaxis presents with bronchospasm, hypotension, angioedema or urticaria. Give adrenaline 0.3 to 0.5mg IM, secure IV access, stop the Pabrinex and follow your local anaphylaxis protocol.

Report every serious adverse reaction through the MHRA Yellow Card scheme and tell your trust medicines governance team.

Quick reference: dosing at a glance

Use this table for rapid bedside reference. Always check the BNF and your trust formulary before prescribing.

How Pabau keeps Pabrinex records audit-ready

Most services still record Pabrinex on a paper drug chart plus a free-text nursing note. The dose and the route usually make it in. The dilution volume, the infusion start time and the resuscitation check often do not, and those are the fields an inspector asks about.

Practice management software like Pabau replaces that with a structured record. The Pabrinex entry carries its own required fields. A clinician cannot sign it off without the diluent, the volume, the infusion window and the monitoring outcome. Private longevity and infusion practices end up with the same trail an NHS ward keeps.

The aftercare sheet then goes out from that same record. Pabau drafts the patient letter, sends it by email or SMS, and stores the acknowledgment against the visit. In IV therapy practices running several infusion rooms, every team member sees the same treatment history and monitoring data.

The outcome is a shorter audit. Nobody has to reconstruct a Pabrinex dose from a paper chart six months later, because the fields were mandatory at the point of care.

Keep every Pabrinex dose audit-ready

Pabau’s clinical records and digital forms capture the diluent, volume, infusion time and monitoring outcome for every Pabrinex dose. Your audit trail is built at the point of care.

Book a demo

Conclusion

Pabrinex is a straightforward drug to prescribe and an easy one to administer badly. The two liquid ampoules go into one syringe. IV gets 50 to 100ml of diluent and at least half an hour. IM gets 7ml, undiluted, high in the gluteal muscle. Those numbers are most of the safety margin.

The trade-off worth remembering is the shortage. Substituting thiamine monohydrate or oral thiamine is reasonable, but neither is equivalent, and both move the documentation burden onto you. Write the unlicensed decision down as you make it, not afterwards.

Use the downloadable sheet above so patients leave with their aftercare instructions in writing. Book a demo to see how Pabau makes the dilution, infusion and monitoring fields mandatory on every Pabrinex record.

Continue your research

Worried about reactions during an infusion? IV therapy complications sets out the reactions to screen for and how to escalate each one.

Need a second aftercare sheet? Vitamin C injection aftercare instructions gives you a patient handout for high-dose ascorbic acid infusions.

Unsure who may administer? Who can administer IV vitamin therapy explains the delegation and supervision rules by role.

Setting up an infusion service? IV therapy EMR software logs each administration with its time, dilution and monitoring outcome.

Frequently asked questions