566
P A R T 6
Drugs acting on the endocrine system
Clinically important drug–drug interactions
The risk of hypermagnesaemia increases if these drugs
are taken with magnesium-containing antacids. This
combination should be avoided.
Reduced absorption of these compounds may occur
if they are taken with cholestyramine or mineral oil
because they are fat-soluble vitamins. If this combination
is used, the drugs should be separated by at least 2 hours.
TABLE 37.4
DRUGS IN FOCUS Parathyroid agents
Drug name
Dosage/route
Usual indications
Antihypocalcaemic agents
calcitriol (Kosteo,
Rocaltrol)
0.5–2 mcg/day PO in the morning
Management of hypocalcaemia and
reduction of parathormone levels
teriparatide (Forteo)
20 mg SC daily
Management of osteoporosis in
postmenopausal women and men with
primary hypogonadal osteoporosis who
do not respond to standard therapy
Antihypercalcaemic agents
Bisphosphonates
alendronate (generic)
10 mg/day PO; for males and for
postmenopausal osteoporosis, 70 mg PO
every week or 10 mg/day PO for treatment,
35 mg PO every week or 5 mg/day PO for
prevention
Treatment of Paget’s disease,
postmenopausal osteoporosis
treatment and prevention, treatment of
glucocorticoid-induced osteoporosis,
osteoporosis in men
clodronate (Bonefos)
Initially, 2400–3600 mg PO daily in divided
doses
Maintenance: 1600 mg PO daily
Treatment of hypercalcaemia in
malignancy; treatment of osteolytic
metastases
etidronate (Didronel)
5–10 mg/kg per day PO
Treatment of Paget’s disease,
postmenopausal osteoporosis,
hypercalcaemia of malignancy, osteolytic
bone lesions in people with cancer
ibandronate (Bondronat)
50 mg PO daily or 6 mg IV q 4 weeks
Treatment of metatstic bone disease
in breast cancer and tumour induced
hypercalcaemia
pamidronate (Aredia)
60–90 mg IV
Treatment of Paget’s disease,
postmenopausal osteoporosis in women,
hypercalcaemia of malignancy, osteolytic
bone lesions in people with cancer
risedronate (Acris,
Actonel)
35 mg PO once weekly or 150 mg PO once
monthly
Treatment of osteoporosis and
preservation of bone mineral density
in patients receiving long-term
corticosteroids
tiludronate (Skelid)
400 mg PO daily for 3 months
Treatment of Paget’s disease
zoledronic acid (Aclasta,
Zometa)
4 mg IV as a single infusion over not less
than 15 minutes (given once a year for
postmenopausal osteoporosis)
Treatment of Paget’s disease,
postmenopausal osteoporosis in women,
hypercalcaemia of malignancy, osteolytic
bone lesions in certain people with
cancer
Calcitonins (salcitonin)
calcitonin salmon
(salcitonin)*
(Miacalcic)
Paget’s disease: 50–100 International Units/
day SC or IM
Hypercalcemia: 4–8 International Units/kg SC
or IM q 12 hours
Treatment of Paget’s disease,
postmenopausal osteoporosis in
conjunction with vitamin D and calcium
supplements; emergency treatment of
hypercalcaemia
* This drug is not available in New Zealand
