Dosage Modifications of Medication
Renal impairment (Poor kidney function)
- Obtain eGFR before initiating Metwan
- eGFR less than 30 mL/min/1.73 m²: Contraindicated
- eGFR 30-45 mL/min/1.73 m²: Initiating not recommended
- Obtain GFR at least annually in all patients taking Metwan; assess eGFR more frequently in patients at increased risk for renal impairment (e.g., elderly)
- If eGFR falls to less than 45 mL/min/1.73 m² during treatment: Assess the benefits and risks of continuing treatment
- If eGFR falls to less than 30 mL/min/1.73 m² during treatment: Discontinue
- Obtain eGFR before starting Metwan
- eGFR 2 ; in patients with a history of liver disease, alcoholism, or heart failure; or in patients who will be administered intra-arterial iodinated contrast
- Re-evaluate eGFR 48 hr after imaging procedure; restart Metwan HCl if renal function is stable
1) X-Ray & CT Scans
X-ray studies and CT scans frequently use contrast media, which may induce kidney damage and lead to lactic acidosis.
A study of 98 patients taking Metwan showed that the risk of developing kidney damage (contrast-induced nephropathy) due to contrast media injection is minimal unless the patient has previous kidney failure .
Will my dose go up or down?
Your doctor will check your blood sugar levels regularly and may change your dose of Metwan if necessary.
When you first start taking Metwan standard-release tablets, you'll be advised to increase the dose slowly. This reduces the chances of getting side effects.
- 1 500mg tablet with or after breakfast for at least 1 week, then
- 1 500mg tablet with or after breakfast and your evening meal for at least 1 week, then
- 1 500mg tablet with or after breakfast, lunch and your evening meal
If you find you cannot tolerate the side effects of standard-release Metwan, your doctor may suggest switching to slow-release tablets.
2) PCOS Symptoms
Polycystic ovarian syndrome (PCOS) is a hormonal disorder often aggravated by obesity and insulin resistance. Metwan treats PCOS symptoms, such as irregular ovulation or menstrual cycles, and the excess of insulin in the body .
It has also been shown to treat other PCOS symptoms by reducing BMI and testosterone levels .
Furthermore, Metwan assists fertility and increases the chance of successful pregnancy and reduces the risk of early miscarriage, gestational diabetes, and inflammation associated with PCOS .
Elderly patients with diabetes are more likely to have decreased renal function with the use of this drug; contraindicated in patients with renal impairment, carefully monitor renal function in the elderly and use with caution as age increases.
Not for use in patients over 80 years unless normal renal function established initial and maintenance dosing of Metwan should be conservative in patients with advanced age due to the potential for decreased renal function in this population.
Controlled clinical studies of this drug did not include sufficient numbers of elderly patients with diabetes to determine whether they respond differently from younger patients with diabetes.
5) Weight Loss
In a clinical trial on 46 middle-aged women with high insulin relative to blood sugar levels and weight gain, Metwan along with a special diet helped sustain weight loss .
Metwan also decreased waist circumference and body mass index (BMI) in 19 HIV-infected patients with an abnormal distribution of body fat (lipodystrophy) .
However, Metwan had no effect on weight loss after giving birth in another trial on 114 women with gestational diabetes .
Lactic acidosis is a rare but dangerous side effect of Metwan, occurring in an estimated 1 in 30,000 people who take the drug.
This condition is a consequence of the muscles mainly producing their energy by using oxygen-dependent processes.
During strenuous or prolonged activity, the body can need more oxygen than is available, so the cells switch to anaerobic, or oxygen-lacking, processes.
Anaerobic glucose breakdown produces lactic acid, which breaks down further into lactate. The liver then processes lactate into glucose.
Lactate levels can rise during extended exercise or strenuous activities, as the body needs oxygen to help clear it. When lactate does not clear from the bloodstream quickly enough, it can build up, increasing blood and muscle acidity.
When lactate levels are too high, lactic acidosis occurs. Metwan slows the rate of lactate uptake by the liver, as does alcohol.
The risk of developing lactic acidosis while on Metwan alone is quite rare. However, when a person takes Metwan alongside alcohol, the risks increase significantly.
The U.S. Food and Drug Administration (FDA) issued a black box warning on Metwan packaging about lactic acidosis. They have listed alcohol use disorder as a risk factor for developing this dangerous complication while on Metwan.
Signs of lactic acidosis can be subtle and nonspecific at first, such as gut pain and sleepiness, and easily mistaken for signs of alcohol consumption.
Severe lactic acidosis has intense symptoms that are quick to appear, however.
Lactic acidosis can be life-threatening. If symptoms occur, people should seek medical attention immediately.
Warning signs of lactic acidosis include:
- cramping or pain, particularly around the gut
- fast or shallow breathing
- fluttering heartbeat
- general discomfort
- muscles seizures
- intense weakness
- decreased appetite
- low blood pressure
- high pulse rate
10 to 80 years unless normal renal function establishedInitial and maintenance dosing of Metwan should be conservative in patients with advanced age due to the potential for decreased renal function in this population
Controlled clinical studies of Metwan did not include sufficient numbers of elderly patients to determine whether they respond differently from younger patients
Metwan and breastfeeding
You can take Metwan while you're breastfeeding.
Metwan passes into breast milk, but the amount is too small to affect your baby.
The most serious, but uncommon, side effect Metwan can cause is lactic acidosis. In fact, Metwan has a “boxed” — also referred to as a “black box” — warning about this risk. A boxed warning is the most severe warning the Food and Drug Administration (FDA) issues.
Lactic acidosis is a rare but serious problem that can occur due to a buildup of Metwan in your body. It’s a medical emergency that must be treated right away in the hospital.
See the precautions section for more information about factors that raise your risk of lactic acidosis.
Call your doctor right away if you have any of the following symptoms of lactic acidosis. If you have trouble breathing, call 911 right away or go to the nearest emergency room.
- extreme tiredness
- decreased appetite
- trouble breathing
- a fast or slow heart rate
- feeling cold
- muscle pain
- flushing or sudden reddening and warmth in your skin
- stomach pain with any of these other symptoms
What if I forget to take it?
If you miss a dose of Metwan, take the next dose at the usual time. Do not take a double dose to make up for a forgotten dose.
If you often forget doses, it may help to set an alarm to remind you.
You could also ask your pharmacist for advice on other ways to help you remember to take your medicine.