Clodronic acid

Clodronic acid (INN) or clodronate disodium (USAN) is a first generation (non-nitrogenous) bisphosphonate. It is an anti-osteoporotic drug approved for the prevention and treatment of osteoporosis in post-menopausal women and men to reduce vertebral fractures, hyperparathyroidism, hypercalcemia in malignancy, multiple myeloma and fracture related pain because of its potent anti-inflammatory and analgesic effects shown as a reduction in inflammatory markers like IL-1β, IL-6, and TNF-α.[1]

Clodronic acid

Clinical data
AHFS/Drugs.com	International Drug Names
ATC code	M05BA02 (WHO)
Identifiers
IUPAC name (Dichloro-phosphono-methyl)phosphonic acid
CAS Number	10596-23-3
PubChem CID	25419
DrugBank	DB00720
ChemSpider	23731
UNII	0813BZ6866
KEGG	D03545
ChEBI	CHEBI:110423
ChEMBL	ChEMBL12318
CompTox Dashboard (EPA)	DTXSID8046959
ECHA InfoCard	100.031.090
Chemical and physical data
Formula	CH4Cl2O6P2
Molar mass	244.88 g·mol^−1
3D model (JSmol)	Interactive image
SMILES ClC(Cl)(P(=O)(O)O)P(=O)(O)O
InChI InChI=1S/CH4Cl2O6P2/c2-1(3,10(4,5)6)11(7,8)9/h(H2,4,5,6)(H2,7,8,9) Key:ACSIXWWBWUQEHA-UHFFFAOYSA-N
(verify)

Use in human medicine

An Italian study compared the analgesic effect of clodronic acid versus acetaminophen in rheumatic condition related pain. Study result show a reduction in pain in favor of clodronic acid that provided more analgesia than 3 grams/day of acetaminophen. Clodronic acid is also used in experimental medicine to selectively deplete macrophages.

Clodronic acid is approved for human use in Canada and Australia, the United Kingdom, where it is marketed as Bonefos, Loron, Clodron and in Italy as Clasteon, Difosfonal, Osteostab and several generics. In other countries is prescribed as a bone resorption inhibitor and antihypercalcemic agent. It is not approved for use in the United States, because it has too many adverse effects.

Use in equine medicine

Clodronic acid is approved for use in horses under the trade name Osphos, for treatment of bone resorptive processes of navicular syndrome. It is given by intramuscular injection at one point in time, with the total dose divided into 2-3 sites on the horse. Clinical effects (e.g. improvement of lameness) after a single treatment can be seen up to 6 months post-treatment.

Adverse reactions and contraindications

Clodronic acid has been shown to have several adverse effects. These include:[2]

• Signs of discomfort, agitation, or colic, usually within 2 hours of treatment.
• Head shaking
• Lip licking

Notes and references

1. Pennanen N, Lapinjoki S, Urtti A, Mönkkönen J (June 1995). "Effect of liposomal and free bisphosphonates on the IL-1 beta, IL-6 and TNF alpha secretion from RAW 264 cells in vitro". Pharmaceutical Research. 12 (6): 916–22. doi:10.1023/A:1016281608773. PMID 7667201. S2CID 46332840.
2. U.S. Food and Drug Administration. "FDA Provides Equine Veterinarians with Important Information about TILDREN and OSPHOS for Navicular Syndrome in Horses". Retrieved 3 January 2015.