Synovitis induced by alendronic acid can present as acute carpal tunnel syndrome

doi:10.1136/bmj.330.7482.74

BMJ 2005;330:74 (8 January), doi:10.1136/bmj.330.7482.74

Paper

DRUG POINTS

Synovitis induced by alendronic acid can present as acute carpal tunnel syndrome

David Gwynne Jones, consultant orthopaedic surgeon¹, Ruth Savage, senior research fellow², John Highton, associate professor of rheumatology²

¹ Department of Orthopaedic Surgery, Dunedin Hospital, Great King Street, Dunedin, 9001, New Zealand, ² Department of Rheumatology, Dunedin Hospital Centre for Adverse Reactions Monitoring, New Zealand Pharmacovigilance Centre, PO Box 913, Dunedin

Correspondence to: D Gwynne Jones David.gwynne-jones{at}stonebow.otago.ac.nz

Introduction

Alendronic acid (Fosamax, Merck) is a potent oral bisphosphonatelicensed for prevention (5 mg daily) and treatment of postmenopausalosteoporosis (70 mg weekly or 10 mg daily).¹

A 69 year old woman had been treated for osteoporosis with disodiumetidronate (Didronel, Procter & Gamble) for four years.She had a history of asthma but was not taking prednisolone.She started taking 70 mg alendronic acid a week but within 24hours of her first dose developed synovitis in her right wristand within 72 hours developed acute carpal tunnel syndrome.Fluid was found in the carpal tunnel when it was decompressed.No organisms or crystals were seen. Laboratory tests have includeda consistently normal C reactive protein and erythrocyte sedimentationrate, calcium 2.41 mmol/l, ferritin 39 µg/l, uric acid0.3 mmol/l, antinuclear antibodies 1/80, and negative extractablenuclear antigens, double stranded DNA, and rheumatoid factor.Nerve conduction studies showed a marked axonal lesion in thesensory median nerve. Alendronic acid was restarted at 10 mgdaily five months later, but she developed pain in multiplejoints after three days. The symptoms recurred on rechallengeat 10 mg on alternate days. She recovered fully when alendronicacid was discontinued.

Discussion

Synovitis is a well recognised cause of carpal tunnel syndrome.This patient had no previous history of carpal tunnel syndromeor evidence of inflammatory arthritis. Rechallenge led to symptomsin multiple joints.

Alendronic acid can cause musculoskeletal pain.² The New ZealandPharmacovigilance Centre (http://carm.otago.ac.nz) holds threeother reports of synovitis occurring in patients taking alendronicacid, one of whom developed a wrist effusion. Synovitis recurredwhen alendronic acid was re-administered after the normal doseinterval of seven days in two patients and at a reduced doseafter 11 days in the third. Alendronic acid should be considereda cause of synovitis or polyarthritis in the absence of anyother pathology.

Contributors: DGJ identified and managed the case surgically,and JH investigated and managed the patient medically. DGJ andRS searched the literature, and RS collated and summarised otheradverse reactions. DGJ is guarantor.

Funding: None.

Competing interests: None declared.

References

Bisphosphonates for osteoporosis. Drug Ther Bull 2001;39: 68-72.[Abstract/Free Full Text]
Sharpe M, Noble S, Spencer CM. Alendronate: an update on its use in osteoporosis. Drugs 2001;61: 999-1039.[Medline]