GLUCARE XR 500MG 30 TAB

Indications

Approved Uses

Adjunct to diet and exercise to improve glycemic control in adults with type 2 diabetes mellitus; may be used as monotherapy or in combination with other antidiabetic agents (including insulin).

Off-Label Uses

Common off-label uses include polycystic ovary syndrome (PCOS) and prediabetes/high-risk patients to delay progression to type 2 diabetes; other uses (e.g., antipsychotic-associated weight gain, gestational diabetes) are situation-dependent and vary by guideline/region.

Dosage & Administration

Dosing by Condition

Type 2 diabetes mellitus (extended-release): start 500 mg orally once daily with the evening meal; increase by 500 mg weekly (or slower) as tolerated; usual effective dose 1000-2000 mg once daily; maximum 2000 mg/day for ER formulations.

Initial Dose

500 mg orally once daily with the evening meal.

Maintenance Dose

1000-2000 mg once daily or in divided doses

Maximum Dose

2000 mg/day (extended-release); 3000 mg/day (immediate-release)

Children's Dosage

Not approved for children under 10 years of age. For immediate-release tablets in children 10-16 years: Initial dose is 500 mg twice daily. Maximum dose is 2000 mg per day. Extended-release tablets are not approved for use in children.

Dose Adjustment Notes

Titrate gradually (e.g., increase by 500 mg at weekly or longer intervals) to minimize GI effects. Assess renal function before initiation and periodically; do not initiate if eGFR <45 mL/min/1.73 m², contraindicated if eGFR <30; if eGFR falls <45 during therapy, reassess risk/benefit and consider dose reduction; discontinue if eGFR <30.

How to Take

Swallow GLUCARE XR (metformin ER) tablets whole with water; do not crush, chew, or split. Take once daily with the evening meal (or with food) to improve GI tolerability.

Side Effects

Common Side Effects

Diarrhea, nausea, vomiting, abdominal bloating, flatulence, anorexia, metallic taste in mouth.

Side Effect Frequency

Very common (≥10%): gastrointestinal effects (diarrhea, nausea, vomiting, abdominal pain, decreased appetite). Common (1-10%): taste disturbance (metallic taste). Very rare (<0.01%): lactic acidosis. Frequency not known/rare: decreased vitamin B12 absorption/deficiency with long-term use; skin reactions; hepatitis/liver function abnormalities.

Safety & Warnings

Contraindications

Contraindicated in: eGFR <30 mL/min/1.73 m²; acute or chronic metabolic acidosis (including DKA); hypersensitivity to metformin. (Not a strict contraindication but avoid/withhold around iodinated contrast in at-risk patients; hepatic impairment/hypoxic states are major precautions due to lactic acidosis risk.)

Warnings & Precautions

Precautions: lactic acidosis risk-assess renal function before and during therapy; temporarily withhold for hypoxia/dehydration/sepsis, major surgery/acute illness; manage iodinated contrast by holding in at-risk patients and restarting after renal function is stable; avoid excessive alcohol; consider periodic vitamin B12 monitoring; swallow XR tablets whole (do not crush/chew).

Drug Interactions

Drug Interactions

Key interactions: iodinated contrast (temporary discontinuation in at-risk patients); alcohol (↑ lactic acidosis risk); carbonic anhydrase inhibitors (e.g., topiramate/acetazolamide) (↑ acidosis risk); cimetidine (↑ metformin levels); drugs that impair renal function or hemodynamics (e.g., diuretics, NSAIDs, ACEi/ARBs) (↑ accumulation risk); insulin/secretagogues (↑ hypoglycemia risk).

Interaction Severity

MAJOR: Iodinated contrast media (hold metformin around contrast in at-risk patients and reassess renal function before restarting); excessive alcohol intake (increases lactic acidosis risk). MODERATE: Carbonic anhydrase inhibitors (e.g., topiramate/acetazolamide) (metabolic acidosis risk), cimetidine and other OCT2/MATE inhibitors (e.g., dolutegravir, ranolazine) (increase metformin exposure), diuretics/NSAIDs/ACEi/ARBs when they precipitate renal impairment (increase metformin accumulation risk), hyperglycemia-inducing drugs (e.g., corticosteroids, thiazides) (reduce glycemic control).

Food Interaction

Take with food (preferably with the evening meal).

Alcohol Interaction

Use with caution; avoid excessive alcohol intake (increases lactic acidosis risk)

Special Populations

Pregnancy

Consult Doctor

Breastfeeding

Caution

Children

Not approved for children under 10 years of age. For immediate-release tablets in children 10-16 years: Initial dose is 500 mg twice daily. Maximum dose is 2000 mg per day. Extended-release tablets are not approved for use in children.

Elderly

Start at lower dose and titrate cautiously; monitor renal function regularly as eGFR declines with age; dose adjustment required based on renal function; contraindicated if eGFR <30 mL/min/1.73m²

Kidney Impairment

eGFR ≥60: usual dosing; eGFR 45-59: continue with periodic monitoring; eGFR 30-44: do not initiate-if already on, consider dose reduction and close monitoring; eGFR <30: contraindicated.

Liver Impairment

Avoid/not recommended in patients with hepatic impairment or clinical/laboratory evidence of hepatic disease (no dose-adjustment strategy is established).

Storage & Patient Advice

Stopping the Medicine

No taper is required, but do not stop without clinician guidance because glycemic control may worsen and alternative therapy/monitoring is needed.

Overdose

Overdose can cause lactic acidosis (GI symptoms, malaise, myalgias, respiratory distress/hyperventilation, hypothermia, hypotension, bradyarrhythmias); treat by stopping metformin, urgent hospital care/supportive management, and hemodialysis to remove metformin and correct acidosis.

Patient Counseling

Take once daily with the evening meal; swallow whole (do not crush/chew/split). GI upset is common initially and usually improves; avoid excessive alcohol. Inform providers before iodinated-contrast imaging or major surgery (may need temporary interruption). Seek urgent care for possible lactic acidosis symptoms (e.g., severe weakness, muscle pain, trouble breathing, abdominal pain, hypothermia). If used with insulin/sulfonylureas, review hypoglycemia signs. Long-term use may lower vitamin B12-report neuropathy symptoms.

Monitoring Requirements

Monitor renal function (eGFR) at baseline and at least annually (more often if elderly or at risk of renal decline); monitor glycemic control (HbA1c about every 3 months until stable then every 3-6 months, plus SMBG as appropriate); consider vitamin B12 periodically (e.g., every 2-3 years or sooner if anemia/neuropathy); monitor for GI intolerance and symptoms of lactic acidosis; hematologic parameters if clinically indicated (e.g., anemia).

Pharmacology

Mechanism of Action

Decreases hepatic glucose production (gluconeogenesis), decreases intestinal glucose absorption, and improves insulin sensitivity by increasing peripheral glucose uptake/utilization (mechanistically associated with AMPK activation).

Onset of Action

Single-dose onset: begins within hours after administration (peak effect ~4-8 hours for extended-release). Clinical glycemic improvement is usually seen within a few days; maximal effect typically occurs within about 1-2 weeks after initiation or dose titration.

Duration of Effect

Approximately 24 hours for extended-release formulations; full therapeutic effect is maintained with once-daily dosing.

Half-Life

Elimination half-life: ~6.2 hours in plasma; ~17.6 hours in whole blood/erythrocytes.

Bioavailability

Oral bioavailability of metformin is approximately 50-60% (formulation-dependent; ER may have similar overall exposure with slower absorption compared with IR).

Metabolism

Not metabolized; excreted unchanged in urine (renal elimination).

Excretion

Eliminated renally, excreted largely unchanged in urine via glomerular filtration and active tubular secretion (majority of absorbed dose; minimal metabolism).

Protein Binding

Negligible.

Product Information

Available Dosage Forms

Extended-release tablet

Composition per Dose

Each extended-release tablet: 500 mg metformin hydrochloride

Generic Availability

Yes

OTC Alternatives

No OTC alternative

Diabetes Type

Type 2

Reviewed by Al Mujtama Pharmacy Medical Review Team. Last reviewed 10-08-2026