How Can This Medicine Affect Other Medicines

7/29/2019 How Can This Medicine Affect Other Medicines

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Use with caution in

Elderly people.

Weak or debilitated people.

Decreased kidney function.

Decreased liver function.

Not to be used in

Children.

Type 1 diabetes (insulin-dependent).

Diabetic keto-acidosis.

Severely decreased liver function.

Severely decreased kidney function.

Severely decreased thyroid gland function.

Problems with the production of natural steroid hormones by the adrenal glands.

Hereditary blood disorders called porphyrias.

Pregnancy.

Breastfeeding.

Allergy to other sulphonylurea medicines, eg gliclazide, glibenclamide.

Allergy to sulphonamide medicines, eg the antibiotic sulfamethoxazole.

This medicine should not be used if you are allergic to any of its ingredients. Please

inform your doctor or pharmacist if you have previously experienced such an allergy.

If you feel you have experienced an allergic reaction, stop using this medicine and

inform your doctor or pharmacist immediately.

Pregnancy and breastfeeding

Certain medicines should not be used during pregnancy or breastfeeding. However,

other medicines may be safely used in pregnancy or breastfeeding providing the

benefits to the mother outweigh the risks to the unborn baby. Always inform your

doctor if you are pregnant or planning a pregnancy, before using any medicine.

This medicine should not be used during pregnancy. Diabetes is usually controlled

using insulin during pregnancy, because this provides a more stable control of blood

sugar. If you get pregnant while taking this medicine, or are planning a pregnancy, you

should seek medical advice from your doctor.

This medicine may pass into breast milk. As this could cause low blood sugar in the

nursing infant, this medicine should not be used by breastfeeding mothers. Discuss this

with your doctor.

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Side effects

Medicines and their possible side effects can affect individual people in different ways.

The following are some of the side effects that are known to be associated with this

medicine. Just because a side effect is stated here, it does not mean that all people using

this medicine will experience that or any side effect.

Disturbances of the gut such as diarrhoea, constipation, nausea or vomiting.

Increased appetite.

Weight gain.

Low blood sugar level (hypoglycaemia).

Headache.

Tinnitus.

Allergic skin reactions such as rash or itching.

Cholestatic jaundice.

Disturbance in the normal numbers of blood cells in the blood.

The side effects listed above may not include all of the side effects reported by the

medicine's manufacturer.

For more information about any other possible risks associated with this medicine,

please read the information provided with the medicine or consult your doctor or

pharmacist.

How can this medicine affect other medicines?

Many medicines can affect blood sugar levels. It is important to tell your doctor or

pharmacist what medicines you are already taking, including those bought without a

prescription and herbal medicines, before you start treatment with this medicine.

Similarly, check with your doctor or pharmacist before taking any new medicines while

taking this one, to ensure that thecombination is safe.

The following medicines may enhance the blood sugar lowering effect of this medicine

and therefore increase the chance of low blood sugar (hypoglycaemia):

ACE inhibitors, eg captopril (these can cause unpredictable drops in blood

sugar)

Anticoagulants, eg warfarin (anticoagulant effect may also be altered if you

are taking an anticoagulant with this medicine your doctor may want to perform

extra monitoring of your blood clotting time or blood sugar.)

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Chloramphenicol

Disopyramide

fibrates, eg clofibrate

fenfluramine

anti-fungals, eg fluconazole, ketoconazole, voriconazole, miconazole

insulin

MAOI antidepressants, eg phenelzine

other antidiabetic tablets

phenylbutazone

large doses of salicylates, eg aspirin (small pain relieving doses do not

normally have this effect)

sulphonamide antibiotics, eg sulfamethoxazole , co-trimoxazole .

Beta-blockers, eg propranolol (including eye drops containing beta-blockers) can

mask some of the signs of low blood sugar, such as increased heart rate and tremor.

They also prolong episodes of low blood sugar and impair recovery back to normal

glucose levels.

The following medicines may increase blood glucose levels. If you start treatment with

any of these your dose of tolbutamide may therefore need increasing:

adrenaline

antipsychotic medicines, eg chlorpromazine, olanzapine

corticosteroids, eg hydrocortisone, prednisolone

diuretics, especially thiazide diuretics, eg bendroflumethiazide

ginkgo biloba supplements

lithium

oestrogens and progesterones, such as those contained in oral contraceptives

protease inhibitors, eg ritonavir.

Rifampicin may reduce the blood level of tolbutamide. If you are prescribed

rifampicin, your dose of tolbutamide may need to be increased to control your blood

sugar.

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Pharmacokinetic data

Protein binding 96%

Metabolism Hepatic (CYP2C19-mediated)

Half-life 4.5 to 6.5 hours

Excretion Renal

Side Effects

1. Hypoglycemia

2. Weight gain

3. Hypersensitivity- Cross-allergicity with sulfonamide

4. Drug Interactions (especially first generation drugs): Increased

hypoglycemia with cimetidine, insulin, salicylates, sulfonamides

Salicylates displace tolbutamide from its binding site on plasma binding proteins which

lead to increase in free tolbutamide concentration and thus hypoglycemic shock.

Chemical Formula C12H18N2O3S

IUPAC Name 3-butyl-1-[(4-methylbenzene)sulfonyl]urea

Brand names

Aglicid

Apo-Tolbutamide

Arkozal

Artosin

Pharmacodynamic

s

Tolbutamide, a first-generation sulfonylurea antidiabetic agent, is used

with diet to lower blood glucose levels in patients with diabetes mellitus

type II. Tolbutamide is twice as potent as the related second-generation

agent glipizide. Tolbutamide lowers blood sugar by stimulating the

pancreas to secrete insulin and helping the body use insulin efficiently.

The pancreas must be able to produce insulin for this drug to work.

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Absorption Readily absorbed following oral administration. Tolbutamide is detectable in

plasma 30-60 minutes following oral administration of a single dose with peak

plasma concentrations occurring within 3-5 hours. Absorption is unaltered if

taken with food but is increased with high pH.

Volume of

distribution

Not Available

Protein

binding

Approximately 95% bound to plasma proteins.

Metabolism Metabolized in the liver principally via oxidation of the p-methyl group

producing the carboxyl metabolite, 1-butyl-3-p-carboxyphenylsulfonylurea. May

also be metabolized to hydroxytolbutamide. Tolbutamide does not undergo

acetylation like antibacterial sulfonamides as it does not have a p-amino group.

Route of

elimination

Unchanged drug and metabolites are eliminated in the urine and feces.

Approximately 75-85% of a single orally administered dose is excreted in the

urine principally as the 1-butyl-3-p-carboxyphenylsulfonylurea within 24 hours.

Half life Approximately 7 hours with interindividual variations ranging from 4-25 hours.

Tolbutamide has the shortest duration of action, 6-12 hours, of the antidiabetic

sulfonylureas.

Clearance Not Available

Toxicity Oral, mouse: LD50 = 2600 mg/kg

Affected

organisms

Humans and other mammals

Pathways Not Available

Dosage

forms

Prices

DrugBank does not sell nor buy drugs. Pricing information is supplied for

informational purposes only.

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Unit description Cost Unit

Tolbutamide 500 mg tablet 0.4 USD tablet


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D

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Drug Interaction

Acebutolol

Acebutolol may decrease symptoms of hypoglycemia and

increase the time required for the body to compensate forhypoglycemia.

Acenocoumarol

Tolbutamide, a strong CYP2C9 inhibitor, may decrease the

metabolism and clearance of Acenocoumarol. Consider alternate

therapy or monitor for changes in Acenocoumarol therapeutic and

adverse effects if Tolbutamide is initiated, discontinued or dose

changed.

Acetylsalicylic

acid

Acetylsalicylic acid increases the effect of the sulfonylurea,

tolbutamide.

AtenololThe beta-blocker, atenolol, may decrease symptoms of

hypoglycemia.

BisoprololThe beta-blocker, bisoprolol, may decrease symptoms of

hypoglycemia.

Bosentan


metabolism and clearance of Bosentan. Consider alternate therapy

or monitor for changes in Bosentan therapeutic and adverse

effects if Tolbutamide is initiated, discontinued or dose changed.

Capecitabine

Capecitabine, a strong CYP2C9 inhibitor, may decrease the

metabolism and clearance of Tolbutamide, a CYP2C9 substrate.

Consider alternate therapy or monitor for changes in Tolbutamide

therapeutic and adverse effects if Capecitabine is initiated,

discontinued or dose changed.

CarvedilolThe beta-blocker, carvedilol, may decrease symptoms of

hypoglycemia.

Celecoxib


metabolism and clearance of Celecoxib. Consider alternate

therapy or monitor for changes in Celecobix therapeutic and

adverse effects if Tolbutamide is initiated, discontinued or dose

changed.

Chloramphenicol

Chloramphenicol may increase the effect of sulfonylurea,

tolbutamide.

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Clofibrate Clofibrate may increase the effect of sulfonylurea, tolbutamide.

Dapsone


metabolism and clearance of Dapsone. Consider alternate therapy

or monitor for changes in Dapsone therapeutic and adverse effectsif Tolbutamide is initiated, discontinued or dose changed.

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How Can This Medicine Affect Other Medicines