Pamidronic Acid

Pharmaceuticals

Pharmaceuticals -> Listed in ZINC15

Warning

H302 (100%): Harmful if swallowed [Warning Acute toxicity, oral]

P264, P270, P301+P317, P330, and P501 (click each P-code to see the statement)

Aggregated GHS information provided per 24 reports by companies from 4 notifications to the ECHA C&L Inventory.

A small number of cases describe symptomatic hypocalcemia following pamidronate administration. In each case, however, patients had pre-existing derangements contributing to their symptoms, including renal insufficiency and low vitamin D levels secondary to lifestyle, previous GI surgery, and medication history. Recommendations for the management of pamidronate overdose include appropriate correction of the electrolyte disturbance and pre-treatment supplementation with calcium and Vitamin D.

The mechanism of action of pamidronate is inhibition of bone resorption. Pamidronate adsorbs to calcium phosphate (hydroxyapatite) crystals in bone and may directly block dissolution of this mineral component of bone. In vitro studies also suggest that inhibition of osteoclast activity contributes to inhibition of bone resorption. Pamidronate also targets farnesyl pyrophosphate (FPP) synthase. Nitrogen-containing bisphosphonates (such as pamidronate, alendronate, risedronate, ibandronate and zoledronate) appear to act as analogues of isoprenoid diphosphate lipids, thereby inhibiting FPP synthase, an enzyme in the mevalonate pathway. Inhibition of this enzyme in osteoclasts prevents the biosynthesis of isoprenoid lipids (FPP and GGPP) that are essential for the post-translational farnesylation and geranylgeranylation of small GTPase signalling proteins. This activity inhibits osteoclast activity and reduces bone resorption and turnover. In postmenopausal women, it reduces the elevated rate of bone turnover, leading to, on average, a net gain in bone mass.

Drug-Induced Liver Injury Severity and Toxicity (DILIst)

pamidronate

DILI Negative

Intravenous

DOI:10.1016/j.drudis.2019.09.022

M05BA03

M - Musculo-skeletal system

QM - Musculo-skeletal system

Pamidronic acid is a second generation, nitrogen containing bisphosphonate that inhibits osteoclast mediated bone loss It has a wide therapeutic index and a long duration of action as it can be given every 3-4 weeks for certain indications. Patients should be counselled regarding the risk of elevated blood urea nitrogen, renal tubular necrosis, and nephrotoxicity.

Bisphosphonates are taken into the bone where they bind to hydroxyapatite. Bone resorption by osteoclasts causes local acidification, releasing the bisphosphonate, which is taken into the osteoclast by fluid-phase endocytosis. Endocytic vesicles become acidified, releasing bisphosphonates into the cytosol of osteoclasts where they act. Osteoclasts mediate resorption of bone. When osteoclasts bind to bone they form podosomes, ring structures of F-actin. Disruption of the podosomes causes osteoclasts to detach from bones, preventing bone resorption. Nitrogen containing bisphosphonates such as pamidronate are known to induce apoptosis of hematopoietic tumor cells by inhibiting the components of the mevalonate pathway farnesyl diphosphate synthase, farnesyl diphosphate, and geranylgeranyl diphosphate. These components are essential for post-translational prenylation of GTP-binding proteins like Rap1. The lack of prenylation of these proteins interferes with their function, and in the case of Rap1, leads to apoptosis. pamidronate also activated caspases 3 and 9 which further contribute to apoptosis.

Pamidronate is not metabolized _in vivo_.

Pamidronate is not metabolized and is exclusively eliminated by renal excretion. Route of Elimination: Pamidronate is not metabolized and is exclusively eliminated by renal excretion. Half Life: The mean ± SD elimination half-life is 28 ± 7 hours

OYY3447OMC

PAMIDRONIC ACID

Established Pharmacologic Class [EPC] - Bisphosphonate

Chemical Structure [CS] - Diphosphonates

Pamidronic acid is a Bisphosphonate.

In patients with a creatinine clearance >90mL/min, a 90mg intravenous dose reached a Cmax of 1.92±1.08µg/mL, with a Tmax of 4h, and an AUC of 10.2±6.95µg\*h/mL. In patients with a creatinine clearance 61-90mL/min, a 90mg intravenous dose reached a Cmax of 1.86±0.50µg/mL, with a Tmax of 4h, and an AUC of 10.7—3.91µg\*h/mL.[A203264 In patients with a creatinine clearance 30-60mL/min, a 90mg intravenous dose reached a Cmax of 1.84±0.58µg/mL, with a Tmax of 4h, and an AUC of 10.1±3.38µg\*h/mL. In patients with a creatinine clearance <30mL/min, a 90mg intravenous dose reached a Cmax of 1.93±0.53µg/mL, with a Tmax of 4h, and an AUC of 34.0±8.37µg\*h/mL.

Pamidronate is exclusively eliminated in the urine. By 120 hours after administration, 46±16% of the dose has been eliminated in the urine.

The mean total clearance of pamidronate is 107±50mL/min and the mean renal clearance is 49±28mL/min.

Use (kg; approx.) in Germany (2009): >10

Pamidronate is in a class of drugs called bisphosphonates. Pamidronate reduces breakdown of the bones. Pamidronate is used in the treatment of Paget's disease of bone; to reduce high levels of calcium in the blood associated with malignancy (cancer); and to reduce the breakdown of bone due to metastases of breast cancer or multiple myeloma. For the treatment of moderate or severe hypercalcemia associated with malignancy