Names and pronunciation
(met-for′min) Glucophage, Glucophage XR, Glumetza, Glycon , Riomet, Riomet ER
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Individual generic drug information
Extracted information for metFORMIN only.
(met-for′min) Glucophage, Glucophage XR, Glumetza, Glycon , Riomet, Riomet ER
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Func. class.: Antidiabetic, oral
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Chem. class.: Biguanide
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Do not confuse: metformin/metroNIDAZOLE
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ACTION: Inhibits hepatic glucose production and increases sensitivity of peripheral tissue to insulin
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USES: Type 2 diabetes mellitus
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Extracted information for metFORMIN only.
CONTRAINDICATIONS: Dia- betic ketoacidosis, metabolic acidosis, renal failure, radiographic contrast use
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Black Box Warning: Lactic acidosis Precautions: Pregnancy, breastfeeding, geriatric patients, previous hypersensitiv- ity, thyroid disease, HF, type 1 diabetes mellitus, hepatic disease, alcoholism, cardiopulmonary disease, acidemia, acute MI, cardiogenic shock, renal dis- ease, heart failure Black Box Warning: Lactic acidosis: malaise, myalgia, abdominal distress; risk increases with age, poor renal func- tion; monitor electrolytes, lactate, pyru- vate, blood pH, ketones, glucose; suspect in any diabetic patient with metabolic acidosis, with ketoacidosis; immediately stop product if hypoxemia or significant renal dysfunction occurs; do not use in those >80 yr unless CCr is normal; alco- hol use may increase lactic acidosis risk • Renal status: obtain BUN, creatinine before use; if elevated, a dose reduction is required • Pregnancy/breastfeeding: avoid use in pregnancy, do not use in breastfeeding; if an antidiabetic is needed during preg- nancy, use insulin Black Box Warning: Lactic acidosis: hyperventilation, fatigue, malaise, chills, myalgia, somnolence; to notify prescriber immediately, stop product; not to use in excessive alcohol intake that is chronic • To regularly self-monitor blood glu- cose with blood-glucose meter • About signs, symptoms of hypoglyce- mia/hyperglycemia; what to do about each (rare) • That product must be continued on daily basis; about consequences of dis- continuing product abruptly; to take as prescribed; not to double doses • To avoid OTC medications, alcohol unless approved by prescriber • That diabetes is a lifelong illness; that product is not a cure, only controls symptoms • To carry emergency ID and glucagon emergency kit • That Glucophage XR tab may appear in stool • To report adverse reactions; if GI upset occurs, it usually decreases over time • To take with meals; not to break, crush, chew ext rel product • Pregnancy: that PCOS patients with insulin resistance may be at risk of con- ception; to use adequate contraception if pregnancy is not desired HIGH ALERT
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SIDE EFFECTS ENDO: Lactic acidosis, hypoglycemia GI: Nausea, vomiting, diarrhea, heart- burn, anorexia, metallic taste
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INTERACTIONS • Do not give with radiologic contrast media; may cause renal failure • Do not use with dofetilide; may cause lactic acidosis Increase: digoxin levels—digoxin; moni- tor digoxin level Increase: metFORMIN level—cimeti- dine, digoxin, morphine, procainamide, quiNIDine, raNITIdine, triamterene, van- comycin; monitor blood glucose Increase: hyperglycemia—calcium chan- nel blockers, corticosteroids, estrogens, oral contraceptives, phenothiazines, sym- pathomimetics, diuretics, phenytoin, β-blockers; monitor blood glucose Drug/Herb Increase: hyperglycemia—glucosamine Increase: hypoglycemia—chromium, coenzyme Q10, garlic, green tea, horse chestnut Drug/Lab Test Decrease: vit B12
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Extracted information for metFORMIN only.
DOSAGE AND ROUTES Type 2 diabetes mellitus • Adult: PO 500 mg bid or 850 mg/day, max 250 mg/day; EXT REL (Gluco- phage XR) 500 mg daily with evening meal, may increase by 500 mg per wk, max 2000 mg/day; (Glumetza) 1000 mg daily with food, preferably with PM meal, may increase by 500 mg per wk, max 2000 mg daily; extended-release sus- pension (Riomet ER) 500 mg daily with every meal Renal dose • Adult: PO eGFR 30-45 mL/min/1.73 m2, avoid use; if eGFR >45 mL/min/1.73 m2 then falls <45 mL/min/1.73 m2, as- sess benefits/risks of treatment; dis- continue if eGFR falls <30 mL/min/1.73 m2
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Available forms: Tabs 500, 850, 1000 mg; ext rel tab 500, 750, 1000 mg; oral sol 500 mg/5 mL; extended-release sus- pension 500 mg/5 mL
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Administer: PO route • Conversion from other oral hypoglyce- mic agents; change may be made without gradual dosage change; monitor serum glu- cose, urine ketones tid during conversion • Store in tight container in cool envi- ronment • Monitor eGFR at least annually • Do not use in dialysis • Immediate rel product: bid given with meals to decrease GI upset and provide the best absorption; immediate rel tabs crushed, mixed with meal, fluids for pa- tients with difficulty swallowing • Ext rel product may also be taken as single dose; titrate slowly to therapeutic response, side effect tolerance • Ext rel tabs: do not chew, break, crush; may be given with evening meal • Oral solution: use calibrated spoon, oral syringe or container to measure; give with meals • Oral extended-release suspen- sion: shake well, use dosing cup, give with evening meal
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Extracted information for metFORMIN only.
Assess: • Hypoglycemic reactions (sweating, weakness, dizziness, anxiety, tremors, hunger); hyperglycemic reactions soon after meals; these occur rarely with prod- uct, may occur when product combined with sulfonylureas • CBC (baseline, q3mo) during treatment; check LFTs periodically, AST, LDH, renal studies: BUN, creatinine during treatment; glucose, A1c; folic acid, vit B12 q1-2yr • Surgery: product should be discontin- ued temporarily for surgical procedures when patient is NPO or if contrast me- dium is used; resume when patient is eating
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Evaluate: • Therapeutic response: decrease in polyuria, polydipsia, polyphagia; clear M sensorium; absence of dizziness; stable gait; blood glucose, A1c at normal level
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CLINICAL CONSIDERATIONS
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Patient and caregiver information:
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Extracted information for metFORMIN only.
PHARMACOKINETICS Excreted by kidneys unchanged 35%- 50%, half-life 6 hr, peak 2-3 hr (immedi- ate release); 7 hr (ext release); 2½ hr (solution)
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Filter the extracted dose blocks for this individual drug.
Type 2 diabetes mellitus
• Adult: PO 500 mg bid or 850 mg/day, max 250 mg/day; EXT REL (Gluco- phage XR) 500 mg daily with evening meal, may increase by 500 mg per wk, max 2000 mg/day; (Glumetza) 1000 mg daily with food, preferably with PM meal, may increase by 500 mg per wk, max 2000 mg daily; extended-release sus- pension (Riomet ER) 500 mg daily with every meal Renal dose
Candidate age grouping · source page 852
Type 2 diabetes mellitus
• Adult: PO eGFR 30-45 mL/min/1.73 m2, avoid use; if eGFR >45 mL/min/1.73 m2 then falls <45 mL/min/1.73 m2, as- sess benefits/risks of treatment; dis- continue if eGFR falls <30 mL/min/1.73 m2
Candidate age grouping · source page 852