PHARMACOLOGICAL PROPERTIES

Transcription

1 ANTİ-FOSFAT ca 700 mg Film Tablet COMPOSITION 1 film tablet contains 700 mg Calcium acetate, as an active ingredient. Excipients are Microcrystalline cellulose, Povidone K30, Crosspovidone, Magnesium stearate, Sucrose, Methylcellulose, Macragol PHARMACOLOGICAL PROPERTIES Pharmacodynamic Properties Calcium ions have critical role in the activation of the biological systems. Sensitivity of excitable membranes depends on extracellular calcium concentration. Calcium ions also take a role in cell membrane permeability. Deficiency of calcium ions increases neuromuscular excitability, whereas excess of calcium ions decreases neuromuscular excitability. Oral calcium intake increases skeletal bones mineralization in case of calcium deficiency. As phosphate binding agent, clinical relevance of calcium acetate is related in producing calcium stones which are not solved in the intestines with phosphate coming from diet. In this process, calcium acetate does not require to be activated by gastric hydrochloride acid. These unsolved compounds are excreted in urine. Maximum phosphate binding capacity ranges between ph 6-8. Therefore, calcium acetate, as phosphate binding agent is convenient in hypo and anacidic patients. Pharmacokinetic Properties Calcium acetate is white, crystalline powder and has hygroscopic properties. It has unpleasant taste and for this reason it should be processed for using in pharmaceutical preparation. Calcium acetate is soluble in water with wide range of ph. Unlike calcium carbonate, calcium acetate readily binds phosphate, when ph > 5. Calcium carbonate needs slight acidic medium and thus, requires regular gastric acidic secretion in order to bind phosphate. Therefore, calcium acetate has a dynamic advantage over calcium carbonate. If ph value is above 6.0, phosphate binding capacity of calcium carbonate significantly decreases. In neutral ph of jejunum, calcium carbonate is not soluble and not able to bind sufficient amount of phosphate. Despite this, since calcium acetate is present in wide range of ph values, it binds phosphate ions and insoluble calcium phosphate in intestine and then this form is excreted in feces. This precipitation reaction directly depends on solubility of calcium acetate, as phosphate binding agent. In case of diets containing phosphate, phosphate binding functions occurs even in stomach irrespective to ph values and then this process continues in intestines. At ph 7.0 calcium phosphate binding capacity reaches up to 100%. For this reason therapeutically desired phosphate precipitation takes places in small intestines where ph values ranges between Calcium acetate produces soluble calcium chloride and acetic acid by reaction with gastric acid. In active solution calcium acetate cleaves into calcium hydroxide and acetic acid. If nutritional phosphate intake is not available, calcium ions are bioavailable and it is absorbed through small intestine. There are two transport mechanisms in intestinal absorption: 1. Vitamin D depended active and saturable transport. 2. Passive transport independent of hormone.

2 Approximately 10 to 36% of calcium dose is expected to be absorbed depending on vitamin D status and dose of calcium intake. In dialysis patients calcium absorption is low, unless vitamin D is supplied. Due to the fact that calcium acetate is more soluble than calcium carbonate in wide ph range, when used with foods, calcium acetate represents more effect on phosphate binding. Therefore, when taken as calcium acetate especially with foods, its absorption is lower than that other calcium forms. In vivo studies indicated that when 59 meq of calcium acetate was taken, 190 mg calcium was absorbed. Whilst same amount of calcium carbonate was taken, 251 mg calcium was absorbed. Calcium absorption (bioavailability) and phosphate binding characteristics are more appropriate for calcium acetate than those of calcium carbonate. With the use of excess calcium carbonate, systemic calcium absorption may increase. However, lower calcium acetate doses are sufficient to bind the same amount of phosphate. Thus, hypercalcemia risk reduces. In clinical studies, phosphate binding capacities of calcium acetate, calcium carbonate, calcium citrate and aluminium hydroxide were compared in various ph levels. In these studies, when ph value is about , only calcium acetate bounded to extra phosphate (100 %). Therefore, phosphate binding capacity of calcium acetate is clearly faster and it occurs within 60 minutes. But, calcium carbonate capacity (at same molar concentrations) depends on ph, and can bind % of phosphate. This value changes after 4 hours to 8% - 80% and after 24 hours to 6% - 93%. Daily mean phosphate intake is approximately mg/kg/day, corresponding to total daily amount of mg. But, this amount varies according to individual and cultural differences. Clinical studies demonstrated that 4.0 g of calcium acetate intake (equivalent to 1000 mg calcium) reduced phosphate resorption of 345 mg ingested phosphate to 89.0 mg. Since mg phosphate will be eliminated after 4 hours of hemodialysis session, decreased phosphate resorption in the intestine is clinically important. This requires g calcium acetate which is equivalent to mg calcium, regardless of any diet restriction. With application of these doses, there is a risk of an increase in calcium levels as mmol. However, this was not confirmed by pharmacokinetic studies. In a series of randomized trials, reduction in hypercalcemic periods and increases in serum calcium levels observed in many patient using calcium acetate. In conclusion, when calcium acetate is chosen as a phosphate binding agent, undesired calcium absorption reduces. During treatment, serum calcium levels must be monitored on regular basis and if necessary dose must be reduced and calcium free phosphate binding agents (aluminium hydroxide, aluminium hydroxychloride must be employed. Also, calcium concentration in dialisate must be adjusted. Hormones control calcium absorption. Absorption decreases with aging and increases in hypocalcemic conditions % of administered 500 mg calcium is absorbed. Administration of higher doses slightly increases absorption extent. In normal diet daily intake accounts for 1000 mg. Calcium is eliminated through kidneys depending on serum calcium levels. 98% of filtered calcium via health kidney is absorbed through glomerular tubulles.

3 INDICATIONS It is indicated for the treatment of high level of serum phosphate (hyperphosphatemia) in patients with renal failure, particularly patients undergoing regular hemodialysis therapy. CONTRAINDICATIONS Anti-Fosfat ca should not be used in conditions of hypercalcemia such as hyperparathyroidism, vitamin D overdose, para-neoplastic syndrome (i.e. bronchial carcinoma, mammary carcinoma, hypernephroma, plasmocytoma) and in patients with bone metastasis, sarcoidosis and immobilisation osteoporosis. Anti- Fosfat ca should only be used in patients with renal failure whose serum and urine calcium levels are monitored regularly; not to be used in patients with adsorptive or renal hypercalciuria, nephrocalcinosis, kidney calcium stones and hypophosphatemia. WARNINGS/PRECAUTIONS Absorptive hypercalciuria risk should be eliminated in patient having anamnesis of family history of urinary calcium stones. PREGNANCY AND LACTATION In humans during pregnancy and lactation periods no harm has been reported with calcium usage. Serum calcium levels should be closely monitored in pregnancy. Long lasting hypercalcemia may produce physical malformation and mental retardation in child. UNDESIRED EFFECTS Even with recommended doses, flatulence in stomach may be observed due to carbondioxide production. In patients with renal insufficiency and patients consuming high doses during long term treatment, it may cause hypercalcemia, metabolic acidosis and hypercalciuria. Hypercalcemia Hypercalcemic episodes may develop in chronic renal failure patients using Anti-Fosfat ca, as a phosphate binding agent, when using vitamin D derived products simultaneously. For this reason, serum calcium and serum phosphate monitoring should be employed regularly. In literature there is an information concerning possibility of developing soft tissue calcification due to long term usage of calcium acetate in patients with renal failure. The relevance of these reports has not been clarified yet. For prophylaxis, the lowest calcium dose is recommended which is determined by serum calcium and phosphate levels. Administration of calcium salts decreases phosphate absorption by producing insoluble calcium phosphate. IN CASE OF AN UNEXPECTED EFFECT, CONSULT YOUR DOCTOR DRUG INTERACTIONS Calcium resorption increases with concomitant uses of vitamin D and vitamin D derived products. Thiazide and diuretics reduce calcium secretion. When calcium and thiazide are taken concomitantly, serum calcium levels must be monitored.

4 Combined usage of Anti-Fosfat ca with tetracyclin, sedofoxim-acsetils, sefuroxim acetil, ketaconazole, 4-quinolons (ciprofloxacin, norfloxacin), iron, fluoride, extramustine preparations may decrease the resorption and efficacy of mentioned products. There must be at least 2 hours intervals between intake of mentioned products and Antifosfat ca. In the case of increased serum calcium level, sensitivity to glycozides, including arrythmia risk may occur. METHOD OF ADMINISTRATION AND DOSE Dose depends on serum phosphate level. Treatment must be initiated with two-three tablets of Anti-Fosfat ca taken with meals (corresponds to mg calcium/day). It is possible to increase daily dose up to 3-4 tablets per meal (corresponding to up to 10 g of Ca acetate daily). During Anti-Fosfat ca therapy serum calcium and serum phosphate levels should be monitored. Calcium phosphate levels should not exceed 5.3 ml mmol 2 /l 2. If exceeds, treatment must be discontinued. OVERDOSE, SIGNS AND SYMPTOMS AND ANTIDOTE There is no overdose report concerning single use of calcium preparations. In case of hypercalcemia, rehydration, isotonic NaCl infusion and forced diuresis are recommended. It is possible to reduce calcium concentration in dialysate for regular hemodialysis patients. ADDITIONAL INFORMATION It is only used in patients for described indication. Serum calcium and serum phosphate levels should be monitored during long term of usage calcium acetate in renal failure. Especially, it is of utmost significance for patients using vitamin D derived products. STORAGE CONDITIONS Do not store above 25 C. Expiry date and Lot no. are printed on the box. Keep out of the reach and sight of children and store in its original package. Commercial Presentation In a carton box of blisters containing 100 film tablets with package insert. Manufacturer Medice Arzneimittel Pütter GmbH & Co.KG, Germany. REGISTRATION HOLDER ASSOS İlaç, Kimya, Gıda Ürünleri Üretim ve Tic. A.Ş. ÜMRANİYE 34773, İSTANBUL REGISTRATION NUMBER: , 112/24 Available only with prescription

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