Implications of obesity for drug administration and absorption from subcutaneous and intramuscular injections: A primer.

PURPOSE: To discuss the potential implications of obesity for drug administration and absorption from subcutaneous (SC) and intramuscular (IM) injection sites. SUMMARY: The SC and IM routes are useful for the parenteral administration of medications to optimize pharmacokinetic properties such as time to onset and duration of effect, for cost considerations, or for ease of administration, such as when intravenous access is unavailable. The choice of SC or IM injection depends on the specific medication, with SC administration preferred for products such as insulin where a slower and more sustained response is desirable, while IM administration is usually preferred for products such as vaccines where more rapid absorption leads to a more rapid antibody response. Obesity has the potential to influence the rate and extent of absorption, as well as adverse effects, of medications administered by the SC or IM route through changes in SC tissue composition and depth or by inadvertent administration of IM medications into SC tissue because of improper needle length. Potential adverse effects associated with IM or SC injections in addition to pain, bruising, and hematoma formation include sciatic nerve injury, particularly with IM injection in the upper outer quadrant of the buttock; bone contusion or rarely osteonecrosis if the IM injection is excessively deep; and granulomas, fat necrosis, and calcification with SC injection. CONCLUSION: Issues related to medication absorption in obese patients are likely to become more prominent in the future with increasing approvals of a wide range of biotherapeutic agents administered by SC injection. Studies should be directed toward these and other agents to assist with dosing decisions in this challenging population.

Subcutaneous injection of IFN alpha-2b for COVID-19: an observational study.

BACKGROUND: The global pandemic of coronavirus disease 2019 (COVID-19) infection is ongoing and associated with high mortality. The aim of this study was to investigate the efficacy and safety of subcutaneous injection of interferon alpha-2b (IFN alpha-2b) combined with lopinavir/ritonavir (LPV/r) in the treatment of COVID-19 infection, compared with that of using LPV/r alone. METHODS: Patients diagnosed with laboratory-confirmed COVID-19 infection in Wuhan Red Cross hospital during the period from January 23, 2020 to March 19, 2020 were included. The length of stay, the time to viral clearance and adverse reactions during hospitalization were compared between patients using oral LPV/r and combined therapy of LPV/r and subcutaneous injection of IFN alpha-2b. RESULTS: A total of 22 patients were treated with LPV/r alone and 19 with combined therapy with subcutaneous injection of IFN alpha-2b. The average length of hospitalization in the combination group was shorter than that of LPV/r group (16 ± 9.7 vs 23 ± 10.5 days; P = 0.028). Moreover, the days of hospitalization in early intervention group decreased from 25 ± 8.5 days to 10 ± 2.9 days compared with delayed intervention group (P = 0.001). Combined therapy with IFN alpha-2b also significantly reduced the duration of detectable virus in the upper respiratory tract. No patient in each group was transferred to intensive care unit (ICU) or died during the treatment. There was no significant difference in the adverse effect composition between two groups. CONCLUSIONS: Subcutaneous injection of IFN alpha-2b combined with LPV/r shortened the length of hospitalization and accelerated viral clearance in COVID-19 patients, which deserves further investigation in clinical practice.