Journal of Human Hypertension (1999) 13, 565–566  1999 Stockton Press. All rights reserved 0950-9240/99 $12.00 http://www.stockton-press.co.uk/jhh CASE REPORT Achilles tendonitis: an unusual complication of amlodipine therapy

A Zambanini1, S Padley2, A Cox1 and MD Feher1 1Section of Clinical Pharmacology, Imperial College School of Medicine, 2Imaging Department, Chelsea & Westminster Hospital, London, UK

Keywords: hypertension; calcium channel blocker; amlodipine; achilles tendonitis; ankle oedema

Introduction of both ankles (Figure 1). These features were asso- ciated with pain on walking and consequently the Calcium channel blocker (CCB) therapy has an 1 patient elected to stop taking the medication. There established role in the treatment of hypertension, had been no concomitant weight change or short- but in a small proportion of patients, the side effect ness of breath while receiving treatment with amlo- profile of these drugs may limit their use. The com- dipine. Within 10 days of drug withdrawal the ankle monest clinical adverse effects include ankle swell- swelling and tendon pain resolved completely but ing, flushing, headache, palpitations and consti- his blood pressure control deteriorated (BP 157– pation.2 We describe an unusual case where ankle 183/105–115 mm Hg). swelling was associated with bilateral achilles ten- donitis. To confirm that this was a drug associated effect, the patient agreed to restart amlodipine. Within 3 weeks there was recurrence of his symptoms with Case report bilateral achilles tendon pain and ankle swelling. A 50-year-old Caucasian male electronics engineer, Ultrasound of the ankles confirmed the presence of presented to the hypertension clinic with a 3-year achilles tendon thickening, with evidence of hyper- history of documented essential hypertension. The aemia on colour Doppler imaging consistent with blood pressure was 150–156/100–102 mm Hg and acute tendonitis (Figure 2). Further investigations there was evidence of grade 1 hypertensive retino- confirmed an ESR of 11 mm/h, and a negative rheu- pathy, dipstick positive proteinuria and a serum cre- matoid factor titre of Ͻ1:40. His symptoms resolved atinine of 118 ␮M/L. Echocardiography confirmed after a further withdrawal of amlodipine therapy. the presence of mild concentric left ventricular Alternative antihypertensive medication was then hypertrophy. Additional cardiovascular risk factors initiated. included hypercholesterolaemia (total cholesterol 5.9 mM/L, calculated LDL 4.0 mM/L). He was a non- smoker with a fasting glucose of 5.3 mM/L. There was no past history of ischaemic heart disease, heart failure or any rheumatological conditions. The patient complained of feeling lethargic on his antihypertensive medication (atenolol 50 mg once a day) and so this was slowly withdrawn. The blood pressure after 3 weeks had increased to 162– 175/106–109 mm Hg and he therefore commenced amlodipine which was gradually increased, over a period of 6 months, to a maximum of 10 mg a day. Within 2 weeks of receiving amlodipine 10 mg a day, the blood pressure had reduced to 142–146/93– 97 mm Hg. However, the patient noted point tender- ness over both achilles tendons with mild swelling

Correspondence: Dr Andrew Zambanini, Section of Clinical Phar- macology, 4th Floor, Chelsea & Westminster Hospital, 369 Ful- Figure 1 Posterior view of both ankles showing localised oedema ham Road, London SW10 9NH, UK around the lateral malleoli. Received 31 March 1999; revised and accepted 30 April 1999 Case report: achilles tendonitis A Zambanini et al 566 viously reported with CCB therapy but may be asso- ciated with painful ankle oedema. Few drugs, namely the fluoroquinolone group of antibiotics7 and isotretinoin,8 have been associated with achilles tendonitis which in some cases may lead to acute tendon rupture. It would therefore be wise to dis- continue amlodipine therapy in cases associated with painful ankle swelling as this may be indica- tive of achilles tendonitis.

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