Alendronic acid

CLINICAL USE

Treatment and prophylaxis of osteoporosis

DOSE IN NORMAL RENAL FUNCTION

5–10 mg daily or 70 mg once weekly

PHARMACOKINETICS

Molecular weight : 249.1 (325.1 as sodium salt)

%Protein binding : 78

%Excreted unchanged in urine : Approx 50

Volume of distribution (L/kg) : 28 litres

half-life – normal/ESRD (hrs) : >10 years/Increased

DOSE IN RENAL IMPAIRMENT

GFR (mL/MIN)

35–50 Dose as in normal renal function <35 Avoid. See ‘Other Information’

DOSE IN PATIENTS UNDERGOING RENAL REPLACEMENT THERAPIES

CAPD : Unlikely to be dialysed. Dose as in GFR<35 mL/min

HD : Not dialysed. Dose as in GFR<35 mL/min

HDF/high flux : Unknown dialysability. Dose as in GFR<35 mL/min

CAV/VVHD : Unlikely to be dialysed. Dose as in GFR<35 mL/min

IMPORTANT DRUG INTERACTIONS

Potentially hazardous interactions with other drugs Calcium salts: reduced absorption of alendronate

ADMINISTRATION

Reconstition

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Route

Oral

Rate of Administration

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Comments

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OTHER INFORMATION

Swallow whole with a glass of water on an empty stomach, at least 30 minutes before breakfast and any other oral medication

Patient should stand or sit upright for at least 30 minutes after taking tablets

Combination therapy with alendronate and intravenous calcitriol, for the treatment of secondary hyperparathyroidism in haemodialysis patients, has been used at a dose of 10 mg alendronate plus IV calcitriol 2 mcg post dialysis to reduce PTH levels. (McCarthy JT, Kao PC, Demick DS, et al. Combination therapy with alendronate and intravenous calcitriol for the treatment of secondary hyperparathyroidism in hemodialysis patients. J Am Soc Nephrol. 1999; 10 Program, 81A–82A.) Manufacturers do not recommend use of alendronate in severe renal impairment due to lack of data

One paper reviewed all the information available and concluded that 50% of the recommended dose may be possible in ESRD, but more trials are required and osteomalacia and adynamic bone disease must first be excluded. (Miller PD. Treatment of osteoporosis in chronic kidney disease and end-stage renal disease. Curr Osteoporos Rep. 2005; 3: 5–12.)

Anecdotally, several renal units use either 70 mg weekly or standard doses of all preparations in patients with CKD 3, 4 and 5 to good effect

See how to identify renal failure stages according to GFR calculation

See how to diagnose irreversible renal disease

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