1. Name Of The Medicinal Product
Glucobay 50
Glucobay 100
2. Qualitative And Quantitative Composition
Acarbose 50mg tablets.
Acarbose 100mg tablets
3. Pharmaceutical Form
Tablet for oral administration.
4. Clinical Particulars
4.1 Therapeutic Indications
Indications
Glucobay is recommended for the treatment of non-insulin dependent (NIDDM) diabetes mellitus in patients inadequately controlled on diet alone, or on diet and oral hypoglycaemic agents.
Mode of action
Glucobay is a competitive inhibitor of intestinal alpha-glucosidases with maximum specific inhibitory activity against sucrase. Under the influence of Glucobay, the digestion of starch and sucrose into absorbable monosaccharides in the small intestine is dose-dependently delayed. In diabetic subjects, this results in a lowering of postprandial hyperglycaemia and a smoothing effect on fluctuations in the daily blood glucose profile.
In contrast to sulphonylureas Glucobay has no stimulatory action on the pancreas.
Treatment with Glucobay also results in a reduction of fasting blood glucose and to modest changes in levels of glycated haemoglobin (HbA1, HbA1c). The changes may be a reduction or reduced deterioration in HbA1 or HbA1c levels, depending upon the patient's clinical status and disease progression. These parameters are affected in a dose-dependent manner by Glucobay.
Following oral administration, only 1-2% of the active inhibitor is absorbed.
4.2 Posology And Method Of Administration
Glucobay tablets are taken orally and should be chewed with the first mouthful of food, or swallowed whole with a little liquid directly before the meal. Owing to the great individual variation of glucosidase activity in the intestinal mucosa, there is no fixed dosage regimen, and patients should be treated according to clinical response and tolerance of intestinal side-effects.
Adults
The recommended initial dose is 50mg three times a day. However, some patients may benefit from more gradual initial dose titration to minimise gastrointestinal side-effects. This may be achieved by initiating treatment at 50mg once or twice a day, with subsequent titration to a three times a day regimen.
If after six to eight weeks' treatment patients show an inadequate clinical response, the dosage may be increased to 100mg three times a day. A further increase in dosage to a maximum of 200mg three times a day may occasionally be necessary.
Glucobay is intended for continuous long-term treatment.
Elderly patients
No modification of the normal adult dosage regimen is necessary.
Children and adolescents under 18 years
The efficacy and safety of acarbose in children and adolescents have not been established. Acarbose is not recommended for patients under the age of 18 years.
4.3 Contraindications
Hypersensitivity to acarbose or any of the excipients, pregnancy and in nursing mothers. Glucobay is also contra-indicated in patients with inflammatory bowel disease, colonic ulceration, partial intestinal obstruction or in patients predisposed to intestinal obstruction. In addition, Glucobay should not be used in patients who have chronic intestinal diseases associated with marked disorders of digestion or absorption and in patients who suffer from states which may deteriorate as a result of increased gas formation in the intestine, e.g. larger hernias.
Glucobay is contra-indicated in patients with hepatic impairment.
As Glucobay has not been studied in patients with severe renal impairment, it should not be used in patients with a creatinine clearance < 25 ml/min/1.73m².
4.4 Special Warnings And Precautions For Use
Hypoglycaemia: When administered alone, Glucobay does not cause hypoglycaemia. It may, however, act to potentiate the hypoglycaemic effects of insulin and sulphonylurea drugs, and the dosages of these agents may need to be modified accordingly. In individual cases hypoglycaemic shock may occur (i.e. clinical sequelae of glucose levels < 1 mmol/L such as altered conscious levels, confusion or convulsions).
Episodes of hypoglycaemia occurring during therapy must, where appropriate, be treated by the administration of glucose, not sucrose. This is because acarbose will delay the digestion and absorption of disaccharides, but not monosaccharides.
Transaminases: Patients treated with acarbose may, on rare occasions, experience an idiosyncratic response with either symptomatic or asymptomatic hepatic dysfunction. In the majority of cases this dysfunction is reversible on discontinuation of acarbose therapy. It is recommended that liver enzyme monitoring is considered during the first six to twelve months of treatment. If elevated transaminases are observed, withdrawal of therapy may be warranted, particularly if the elevations persist. In such circumstances, patients should be monitored at weekly intervals until normal values are established.
4.5 Interaction With Other Medicinal Products And Other Forms Of Interaction
Intestinal adsorbents (e.g. charcoal) and digestive enzyme preparations containing carbohydrate splitting enzymes (e.g. amylase, pancreatin) may reduce the effect of Glucobay and should not therefore be taken concomitantly.
The concomitant administration of neomycin may lead to enhanced reductions of postprandial blood glucose and to an increase in the frequency and severity of gastro-intestinal side-effects. If the symptoms are severe, a temporary dose reduction of Glucobay may be warranted.
The concomitant administration of cholestyramine may enhance the effects of Glucobay, particularly with respect to reducing postprandial insulin levels. In the rare circumstance that both acarbose and cholestyramine therapy are withdrawn simultaneously, care is needed as a rebound phenomenon has been observed with respect to insulin levels in non-diabetic subjects.
In individual cases acarbose may affect digoxin bioavailability, which may require dose adjustment of digoxin. Monitoring of serum digoxin levels should be considered.
In a pilot study to investigate a possible interaction between Glucobay and nifedipine, no significant or reproducible changes were observed in the plasma nifedipine profiles.
4.6 Pregnancy And Lactation
The use of Glucobay is contra-indicated in pregnancy and in nursing mothers.
The safety of this medicinal product for use in human pregnancy has not been established. An evaluation of experimental animal studies does not indicate direct or indirect harmful effects with respect to reproduction, development of the embryo or foetus, the course of gestation, and peri- and postnatal development.
4.7 Effects On Ability To Drive And Use Machines
None known.
4.8 Undesirable Effects
Owing to its mode of action, Glucobay results in a greater proportion of dietary carbohydrate being digested in the large bowel. This carbohydrate may also be utilised by the intestinal flora, resulting in the increased formation of intestinal gas. The majority of patients are therefore likely to experience one or more symptoms related to this, particularly flatulence, borborygmi, and a feeling of fullness. Abdominal distension, abdominal pain, softer stools and diarrhoea may occur, particularly after sugar or sucrose-containing foods have been ingested. Uncommonly nausea may occur. Very rarely subileus/ileus may occur.
The symptoms are both dose and dietary substrate related, and may subside with continued treatment. Symptoms can be reduced by adherence to the prescribed diabetic diet and the avoidance of sucrose or foodstuffs containing sugar. If symptoms are poorly tolerated, a reduction in dosage is recommended.
Should diarrhoea persist, patients should be closely monitored and the dosage reduced, or therapy withdrawn, if necessary.
The administration of antacid preparations containing magnesium and aluminium salts, e.g. hydrotalcite, has been shown not to ameliorate the acute gastro-intestinal symptoms of Glucobay in higher dosage and should therefore not be recommended to patients for this purpose.
Rarely, clinically relevant abnormal liver function tests (3 times above the upper limit of normal range) were observed. (See Section 4.4). Very rarely, jaundice and hepatitis have been reported. Individual cases of fulminant hepatitis with fatal outcome have been reported in Japan. The relationship to acarbose is unclear.
Skin reactions may occur rarely. Very rarely oedema has been reported.
4.9 Overdose
No information on overdosage is available. No specific antidotes to Glucobay are known.
Intake of carbohydrate-containing meals or beverages should be avoided for 4-6 hours.
Diarrhoea should be treated by standard conservative measures.
5. Pharmacological Properties
5.1 Pharmacodynamic Properties
In all species tested, acarbose exerts its activity in the intestinal tract. The action of acarbose is based on the competitive inhibition of intestinal enzymes (α-glucosidases) involved in the degradation of disaccharides, oligosaccharides, and polysaccharides. This leads to a dose-dependent delay in the digestion of these carbohydrates. Glucose derived from these carbohydrates is released and taken up into the blood more slowly. In this way, acarbose reduces the postprandial rise in blood glucose, thus reducing blood glucose fluctuations.
5.2 Pharmacokinetic Properties
Following administration, only 1-2% of the active inhibitor is absorbed.
The pharmacokinetics of Glucobay were investigated after oral administration of the 14C-labelled substance (200mg) to healthy volunteers. On average, 35% of the total radioactivity (sum of the inhibitory substance and any degradation products) was excreted by the kidneys within 96 h. The proportion of inhibitory substance excreted in the urine was 1.7% of the administered dose. 50% of the activity was eliminated within 96 hours in the faeces. The course of the total radioactivity concentration in plasma was comprised of two peaks. The first peak, with an average acarbose-equivalent concentration of 52.2 ± 15.7μg/l after 1.1 ± 0.3 h, is in agreement with corresponding data for the concentration course of the inhibitor substance (49.5 ± 26.9μg/l after 2.1 ± 1.6 h). The second peak is on average 586.3 ± 282.7μg/l and is reached after 20.7 ± 5.2 h. The second, higher peak is due to the absorption of bacterial degradation products from distal parts of the intestine. In contrast to the total radioactivity, the maximum plasma concentrations of the inhibitory substance are lower by a factor of 10-20. The plasma elimination half-lives of the inhibitory substance are 3.7 ± 2.7 h for the distribution phase and 9.6 ± 4.4 h for the elimination phase.
A relative volume of distribution of 0.32 l/kg body-weight has been calculated in healthy volunteers from the concentration course in the plasma.
5.3 Preclinical Safety Data
Acute toxicity
LD50 studies were performed in mice, rats and dogs. Oral LD50 values were estimated to be> 10g/kg body-weight. Intravenous LD50 values ranged from 3.8g/kg (dog) to 7.7g/kg (mouse).
Sub-chronic toxicity
Three month studies have been conducted in rats and dogs in which acarbose was administered orally by gavage.
In rats, daily doses of up to 450mg/kg body-weight were tolerated without drug-related toxicity.
In the dog study, daily doses of 50-450mg/kg were associated with decreases in body-weight. This occurred because dosing of the animals took place shortly before the feed was administered, resulting in the presence of acarbose in the gastro-intestinal tract at the time of feeding. The pharmacodynamic action of acarbose led to a reduced availability of carbohydrate from the feed, and hence to weight loss in the animals. A greater time interval between dosing and feeding in the rat study resulted in most of the drug being eliminated prior to feed intake, and hence no effect on body-weight development was observed.
Owing to a shift in the intestinal α-amylase synthesis feedback mechanism a reduction in serum α-amylase activity was also observed in the dog study. Increases in blood urea concentrations in acarbose-treated dogs also occurred, probably as a result of increased catabolic metabolism associated with the weight loss.
Chronic toxicity
In rats treated for one year with up to 4500ppm acarbose in their feed, no drug-related toxicity was observed. In dogs, also treated for one year with daily doses of up to 400mg/kg by gavage, a pronounced reduction in body-weight development was observed, as seen in the sub-chronic study. Again this effect was due to an excessive pharmacodynamic activity of acarbose and was reversed by increasing the quantity of feed.
Carcinogenicity studies
In a study in which Sprague-Dawley rats received up to 4500ppm acarbose in their feed for 24-26 months, malnutrition was observed in animals receiving the drug substance. A dose-dependent increase in tumours of the renal parenchyma (adenoma, hypernephroid carcinoma) was also observed against a background of a decrease in the overall tumour rate. When this study was repeated, an increase in benign tumours of testicular Leydig cells was also observed. Owing to the malnutrition and excessive decrease in bodyweight gain these studies were considered inadequate to assess the carcinogenic potential of acarbose.
In further studies with Sprague-Dawley rats in which the malnutrition and glucose deprivation were avoided by either dietary glucose supplementation or administration of acarbose by gavage, no drug-related increases in the incidences of renal or Leydig cell tumours were observed.
In an additional study using Wistar rats and doses of up to 4500ppm acarbose in the feed, neither drug-induced malnutrition nor changes in the tumour profile occurred. Tumour incidences were also unaffected in hamsters receiving up to 4000ppm acarbose in the feed for 80 weeks (with and without dietary glucose supplementation).
Reproductive toxicity
There was no evidence of a teratogenic effect of acarbose in studies with oral doses of up to 480mg/kg/day in rats and rabbits.
In rats no impairment of fertility was observed in males or females at doses of up to 540mg/kg/day. The oral administration of up to 540mg/kg/day to rats during foetal development and lactation had no effect on parturition or on the young.
Mutagenicity
The results of a number of mutagenicity studies show no evidence of a genotoxic potential of acarbose.
6. Pharmaceutical Particulars
6.1 List Of Excipients
Glucobay tablets contain the following excipients:
Microcrystalline cellulose
Highly dispersed silicon dioxide
Magnesium stearate
Maize starch
6.2 Incompatibilities
None stated.
6.3 Shelf Life
36 months.
6.4 Special Precautions For Storage
The tablets should be stored in the manufacturer's original container in a dry place at temperatures below 25°C.
6.5 Nature And Contents Of Container
Blister strips comprising 300μm polypropylene foil (colourless) with a 20μm soft aluminium backing foil, in cardboard outers.
Pack sizes: 10, 30, 90, 100, 500
21, 42, 84, 420
6.6 Special Precautions For Disposal And Other Handling
None stated.
7. Marketing Authorisation Holder
Bayer plc
Bayer House
Strawberry Hill
Newbury
Berkshire
RG14 1JA
Trading as Baypharm or Baymet.
8. Marketing Authorisation Number(S)
PL 0010/0171
PL 0010/0172
9. Date Of First Authorisation/Renewal Of The Authorisation
28 May 1993/16 February 2004
10. Date Of Revision Of The Text
July 2005
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