# Comparison of Sublingual and Intramuscular Vitamin B12 in Children With Nutritional Vitamin B12 Deficiency Megaloblastic Anemia

## TL;DR

This study compares sublingual and intramuscular vitamin B12 treatments in children with anemia and finds both are equally effective.

## Contribution

The study provides evidence that sublingual vitamin B12 is a viable, noninvasive alternative to intramuscular administration in children.

## Key findings

- Both sublingual and intramuscular vitamin B12 significantly increased hemoglobin and corrected B12 levels in children.
- Sublingual B12 achieved comparable efficacy to intramuscular B12 with no adverse events reported.
- 80.8% of participants reached a nonanemic status after 12 weeks of treatment.

## Abstract

Background and aim

Vitamin B12 deficiency remains a major cause of nutritional anemia in children, particularly in low- and middle-income countries. While intramuscular (IM) vitamin B12 is the traditional treatment, the sublingual route offers a simpler, painless alternative with potentially comparable efficacy. Thus, this study was planned to compare the efficacy of sublingual versus IM vitamin B12 supplementation in children with confirmed vitamin B12 deficiency anemia.

Materials and methods

A prospective comparative study was conducted among children aged 1-15 years at a tertiary care center in Uttar Pradesh. Participants were randomized by using a computer-generated table into two groups: Group A received IM vitamin B12, and Group B received sublingual vitamin B12 for 12 weeks. Blinding of study subjects or the investigating officer was not possible due to obvious differences in the routes of administration of the drugs (IM vs. sublingual). However, the outcome assessors, including the laboratory personnel and the statistician, were blinded to avoid bias. The allocation concealment was performed using the sequentially numbered, opaque, sealed envelopes (SNOSE) method to minimize selection bias by the investigating officer. Hematological parameters, such as hemoglobin (Hb), mean corpuscular volume, total leucocyte count, platelet count, and serum B12, were evaluated at baseline, one month, and three months. Our primary outcome measures were correction of anemia beyond WHO age-specific thresholds and correction of B12 levels to >300 pg/mL as per the Indian Academy of Pediatrics guidelines.

Results

A total of 73 patients (Group A: 36 and Group B: 37) with comparable baseline clinical and hematological characteristics participated in the study. The baseline mean ± SD Hb levels were 8.33 ± 1.14 g/dL in Group A and 8.46 ± 1.24 g/dL in Group B, while the mean ± SD B12 levels were 132.53 ± 38.33 pg/mL and 141.20 ± 31.65 pg/mL in Groups A and B, respectively. The mean ± SD Hb levels at three months were 12.07 ± 0.78 g/dL and 12.31 ± 0.73 g/dL in Group A and Group B, respectively, showing a significant increase from baseline, although the results were comparable across both groups. Statistically significant increments of serum B12 levels (Group A: 329.30 ± 34.94 pg/mL; Group B: 337.08 ± 44.19 pg/mL) were also noted. Normalization of B12 levels was achieved in 100%, while a nonanemic status was achieved in 80.8% (59/73) of the participants. Both routes were well tolerated, and no adverse events were noted during the study period.

Conclusions

Sublingual vitamin B12 is as effective as IM administration for pediatric B12 deficiency anemia. Although the parenteral route remains the gold standard in cases with neurological involvement or severe thrombocytopenia, the sublingual route may be considered for maintenance therapy, as it is a noninvasive, child-friendly alternative that also offers a distinct cost benefit. Therefore, the sublingual route may be considered a potential option, pending evidence from larger, multicenter trials with longer follow-up periods.