Clinical Efficacy and Safety of Teriparatide Versus Alendronate in Postmenopausal Osteoporosis: A Systematic Review of Randomized Controlled Trials

Alendronate, a second-generation bisphosphonate, remains the first-line therapeutic option for postmenopausal osteoporosis. It acts on the bone resorbing osteoclasts causing their apoptosis. This is achieved by producing toxic adenosine triphosphate (ATP) analogues and interfering with the mevalonate pathway. Teriparatide, a recombinant form of parathyroid hormone, is an alternative option to this more conventional drug. It is an anabolic drug that mediates its biological effect via specific, high-affinity membrane cell-surface receptors expressed on the osteoblasts. It promotes bone formation more than bone resorption. Hence, this research was conducted to delineate the effectiveness and clinical safety of teriparatide as compared to alendronate in women suffering from postmenopausal osteoporosis. An extensive search was conducted through PubMed, Google Scholar, Trip (Turning Research into Practice), and Cochrane Central Register of Controlled Trials (CENTRAL) including studies published between August 2017 and October 2024 in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines 2020. The Medical Subject Headings (MeSH) terms and Boolean operators used were "Alendronate" OR "Diphosphonates" OR "Teriparatide" OR "Treatment Outcome" OR "Postmenopause" AND "Osteoporosis". Randomized controlled trials were included in this systematic review. Five full-text articles were ultimately considered and critical appraisal was performed thereon. The annual incidence rate of morphometric vertebral fracture in the sequential therapy (teriparatide) group (0.1020 and 0.1334) was significantly lower than monotherapy (alendronate) (0.1492 and 0.1734). Quality of life (QoL) by week 12 was better in teriparatide than alendronate and no patient encountered any severe adverse effects with teriparatide after 72 weeks of treatment. Thus, based on the results, teriparatide is more effective than alendronate in increasing the bone mineral density (BMD) of L2-4 vertebrae and the hip bone. However, alendronate is better in the case of femoral neck fractures. Furthermore, spinal strength shows a better response in the trabecular than peripheral compartment with teriparatide. Teriparatide is also safer than alendronate due to its lower incidence rate in morphometric vertebral fracture, lack of severe adverse effects and better QoL. Teriparatide showed comparable inhibition of vertebral collapse, increase in BMD, promotion of bone union, and improvement of pain.