Thiamine (B1) Injection

Thiamine (B1) Injection

Available presentation(s): 5 mL. Verify the exact concentration and total active quantity on the prescription and dispensing label.

Introduction: Thiamine (vitamin B1) is an essential cofactor in carbohydrate metabolism. Parenteral thiamine is used for suspected/confirmed deficiency, including Wernicke encephalopathy risk, especially when oral absorption or urgent treatment is inadequate.

Dosage: Dosing varies substantially by prophylaxis versus treatment and by local Wernicke encephalopathy protocols. Follow NZF/hospital guidance; give before or with carbohydrate in at-risk patients. The 100 mg/mL presentation must be prescribed in milligrams with route, frequency and duration.

Mechanisms of Action: Converted to thiamine pyrophosphate, a cofactor for pyruvate dehydrogenase, alpha-ketoglutarate dehydrogenase, branched-chain ketoacid dehydrogenase and transketolase.

Contraindications & Precautions: Parenteral administration can rarely cause severe anaphylaxis; administer where resuscitation is available, particularly with IV doses. Do not delay treatment when Wernicke encephalopathy is suspected.

Interactions: Loop diuretics may increase thiamine loss. Fluorouracil can impair thiamine metabolism. Sulfite-containing solutions may degrade thiamine; verify compatibility.

Adverse Reactions / Side Effects: Injection-site pain, nausea, sweating, restlessness, rash and pruritus may occur. Rare reactions include bronchospasm, hypotension, angioedema and anaphylaxis.

Pregnancy & Breastfeeding: Treat deficiency promptly during pregnancy and breastfeeding. Use high-dose parenteral therapy when clinically indicated; thiamine is compatible with lactation at replacement doses.

Storage: Store under the conditions stated on the Optimus dispensing label and product-specific worksheet. Protect from light where labelled. Do not freeze unless explicitly validated. Maintain cold chain if the label requires refrigeration. Do not use after the assigned beyond-use date or if there is visible particulate matter, precipitation, colour change, loss of container integrity or evidence of improper storage. Once entered, follow the validated in-use time; do not assume a compounded vial is multi-dose.

References

• New Zealand Formulary (NZF), current online edition; product-specific approved data sheets where available; USP Pharmaceutical Compounding—Sterile Preparations; and Optimus Healthcare validated formulation, sterility/endotoxin controls and assigned beyond-use date.
• DailyMed. Thiamine Hydrochloride, Pyridoxine Hydrochloride, Hydroxocobalamin and Levocarnitine injection labels, current editions. https://dailymed.nlm.nih.gov/
• NIH Office of Dietary Supplements. Health Professional Fact Sheets (vitamins and minerals), current online editions. https://ods.od.nih.gov/factsheets/list-VitaminsMinerals/