netilmicin , a semi - synthetic aminoglycoside , is highly effective against gram negative infections of the urinary tract ( uti ) , skin and skin structure ( ssti ) , and lower respiratory tract ( rti ) , as well as in intraabdominal infections and septicemia . its major advantages are comparable or superior efficacy over other aminoglycosides , good clinical efficacy against gentamicin - resistant strains with relatively reduced ototoxicity and nephrotoxicity . hypocalcemia manifesting as carpopedal spasm with this drug has not been reported till date . here we report two cases of carpopedal spasm following use of netilmicin prescribed for genitourinary surgery . a 12-year - old boy had to undergo operative procedure for epispadias and was on surgical prophylaxis with netilmicin 150 mg i.v . twice daily and ceftriaxone ( 500 mg ) the boy received both the drugs for 3 days ( six doses ) following which he developed severe spasm of the feet and hands [ figures 13 ] . on observation the patient was irritable , there was flexion of the hands at the wrists and of the fingers at the metacarpophalangeal joints and extension of the fingers at the inter - phalangeal joints ; the feet were dorsiflexed at the ankles and the toes plantar flexed . immediate laboratory investigation revealed the following picture : serum calcium 7.2 mg / dl ( normal , 8.7 - 11 mg / dl ) , potassium 3.9 mmol / l ( normal , 3.5 - 5.5 mmol / l ) , and sodium of 145 mmol / l ( normal , 135 - 155 mmol / l ) , serum creatinine 3.0 mg / dl and serum albumin 3.4 g / dl ( normal , 3.8 - 4.4 g / dl ) with normal urine output . total bilirubin , serum glutamic oxaloacetic transaminase ( sgot ) , and serum glutamic - pyruvic transaminase ( sgpt ) were also normal . assuming that the patient developed drug - induced nonoliguric renal failure ; both the drugs were withdrawn and the surgery postponed . 24 h following this episode the laboratory investigations were repeated , which showed serum calcium 9.3 mg / dl , potassium , 3.9 mmol / l , sodium 144 mmol / l and serum albumin 4.2 g / dl [ table 1 ] . on recovery , but after 3 days ( 4 doses ) postoperatively the patient developed the same features of carpopedal spasm with laboratory findings of hypocalcemia . on withdrawal of netilmicin and calcium supplementation carpal spasm ( left hand ) carpal spasm ( right hand ) laboratory findings of netilmicininduced carpopedal spasm a 8-year - old boy diagnosed to be a case of hypospadias was given netilmicin 150 mg i.v . once daily as surgical prophylaxis for 2 days and was operated on the second day . netilmicin in the same dose was continued postoperatively , but following the fifth dose , the child developed the characteristic features of tetany . laboratory findings revealed low serum calcium ( 7.6 mg / dl ) , high serum creatinine ( 2.5 mg / dl ) [ table 1 ] . urine output was normal with serum electrolytes ( na and k ) within the normal range . assuming that the reaction was due to hypocalcemia induced by netilmicin , it was withdrawn and supplemented with piperacillin + tazobactum . a 12-year - old boy had to undergo operative procedure for epispadias and was on surgical prophylaxis with netilmicin 150 mg i.v . twice daily and ceftriaxone ( 500 mg ) the boy received both the drugs for 3 days ( six doses ) following which he developed severe spasm of the feet and hands [ figures 13 ] . on observation the patient was irritable , there was flexion of the hands at the wrists and of the fingers at the metacarpophalangeal joints and extension of the fingers at the inter - phalangeal joints ; the feet were dorsiflexed at the ankles and the toes plantar flexed . immediate laboratory investigation revealed the following picture : serum calcium 7.2 mg / dl ( normal , 8.7 - 11 mg / dl ) , potassium 3.9 mmol / l ( normal , 3.5 - 5.5 mmol / l ) , and sodium of 145 mmol / l ( normal , 135 - 155 mmol / l ) , serum creatinine 3.0 mg / dl and serum albumin 3.4 g / dl ( normal , 3.8 - 4.4 g / dl ) with normal urine output . total bilirubin , serum glutamic oxaloacetic transaminase ( sgot ) , and serum glutamic - pyruvic transaminase ( sgpt ) were also normal . assuming that the patient developed drug - induced nonoliguric renal failure ; both the drugs were withdrawn and the surgery postponed . 24 h following this episode the laboratory investigations were repeated , which showed serum calcium 9.3 mg / dl , potassium , 3.9 mmol / l , sodium 144 mmol / l and serum albumin 4.2 g / dl [ table 1 ] . on recovery , but after 3 days ( 4 doses ) postoperatively the patient developed the same features of carpopedal spasm with laboratory findings of hypocalcemia . on withdrawal of netilmicin and calcium supplementation carpal spasm ( left hand ) carpal spasm ( right hand ) laboratory findings of netilmicininduced carpopedal spasm a 8-year - old boy diagnosed to be a case of hypospadias was given netilmicin 150 mg i.v . once daily as surgical prophylaxis for 2 days and was operated on the second day . netilmicin in the same dose was continued postoperatively , but following the fifth dose , the child developed the characteristic features of tetany . laboratory findings revealed low serum calcium ( 7.6 mg / dl ) , high serum creatinine ( 2.5 mg / dl ) [ table 1 ] . urine output was normal with serum electrolytes ( na and k ) within the normal range . assuming that the reaction was due to hypocalcemia induced by netilmicin , it was withdrawn and supplemented with piperacillin + tazobactum . carpopedal spasm ( seen in tetany ) is usually caused by low ionized serum calcium concentration , which causes increased excitability of peripheral nerves resulting in carpopedal spasm , convulsion , and stridor . the total serum calcium < 8.5 mg / dl may be associated with tetany . we reported here two cases of carpopedal spasm caused by netilmicin . a dose dependent nephrotoxicity occurs with aminoglycoside therapy despite adequate fluid volume control and drug level monitoring . renal electrolyte wasting is occasionally caused by symptomatic hypomagnesemia , hypocalcemia , and hypokalemia when treated with these drugs but tetany has not been frequently reported except for a single report on paramomycin . several risk factors , like volume depletion , sepsis , liver and renal dysfunction , hypokalemia , hypomagnesemia , advanced age , prolonged therapy , type of aminoglycoside , time and frequency of dosing , an elevated serum aminoglycoside concentration , and interactions with other nephrotoxic drugs such as vancomycin , amphotericin b , piperacillin , cephalosporins , foscarnet , allopurinol , nsaids , inhibitors of angiotensin converting enzyme , cyclosporine , and cisplatin have been identified . among all aminoglycosides , netilmicin stands out clear because of its least toxicity and superior clinical efficacy , even in some resistant microorganisms . though studies show a clear benefit of the ceftriaxone - netilmicin combination , their potential for interaction can not be overlooked . therefore netilmicin and ceftriaxone being nephrotoxic , both may be the suspects in the case report one . but it was also observed that , netilmicin prescribed alone in once daily dose later on ( in case report one ) and even half the dose ( in case report two ) also resulted in hypocalcemia and carpopedal spasm ( tetany ) . in both the cases , laboratory findings with regard to serum electrolytes , urea , creatinine , other causes of hypocalcemia like vitamin d deficiency , chronic renal failure , hypoparathyroidism were ruled out in both the cases . another important point to be noted here that , though majority of patients in this hospital setup are being given netilmicin alone / netilmicin + ceftriaxone in combination , this type of adverse effects are seldom reported . therefore netilmicin is probably the drug responsible for this rare adverse effect in these two cases ( causality assessment using naranjo 's adverse drug reaction probability score = score 7 and who - umc causality assessment scale ) . netilmicin has long been used both alone and in combination with ceftriaxone in the adult and pediatric population for the treatment of severe gram negative infections in hospital settings . judicious use of such drugs is required to prevent untoward side effects like tetany and its associated disability . identifying high risk patients and quick recognition of drug - induced injury with prompt cessation of the offending drug is the key to managing such cases before the injury causes permanent damage to the renal tissue .
aminoglycoside - induced nephrotoxicity is not uncommon . 
 netilmicin being a member of gentamicin family has the advantage of being relatively free from ototoxicity and nephrotoxicity and is also prescribed for gentamicin resistant cases . in spite of these benefits with netilmicin , occasional development of symptomatic hypomagnesemia , hypocalcemia , and hypokalemia due to renal electrolyte wasting can not be ruled out . 
 here we describe two cases of carpopedal spasm due to hypocalcemia following use of netilmicin .