Metanx dosage, forms, and strengths

Metanx is a brand-name medical food prescribed for diabetic neuropathy or diabetic ulcers. Each capsule contains vitamin B6 (pyridoxal), vitamin B9 (methylfolate), vitamin B12 (methylcobalamin), and algae powder. These nutrients help to improve blood flow to damaged nerves or skin tissues, helping them recover. Two capsules are taken daily either in a single or divided dose. People can choose between regular Metanx and Metanx FC (for “Free and Clear”), a fully vegetarian, dye-free version.

Metanx forms and strengths

Metanx comes in only one dosage form: capsules.

• Capsules: 

  • 3 mg L-methylfolate calcium (vitamin B9)

  • 35 mg pyridoxal-5-phosphate (vitamin B6)

  • 2 mg methylcobalamin (vitamin B12)

  • 90.314 mg algae powder (Schizochytrium)

Metanx dosage for adults

Metanx is prescribed to people with diabetes who have peripheral nerve damage or ulcers due to blood vessel problems. The B vitamins in Metanx decrease the body’s production of a substance that damages the inner lining of blood vessels as well as other health benefits such as aiding nerve growth.

Metanx is a high-dose B vitamin supplement, so use it only under the medical supervision of a healthcare professional. Most people can take Metanx without any safety worries. Only people who have had an allergic reaction to Metanx capsules cannot safely take this supplement.

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Metanx dosage for diabetic peripheral neuropathy

Diabetes is diagnosed in people with persistently high blood sugar. It is a progressive disease in which the excess sugar in the blood gradually damages blood vessels, leading to peripheral nerve damage, kidney damage, retinal damage, cardiovascular disease, and other problems. The standard treatment for diabetes is to manage blood glucose levels using oral antidiabetics (for Type 2 diabetes) or insulin injections (for both Type 1 and Type 2 diabetes) in conjunction with a healthy diet and exercise.

High blood sugar primarily damages the inner lining of the blood vessels, called the endothelium. This inner lining gradually stops functioning properly, a condition called endothelial dysfunction. This compromises blood flow and eventually leads to nerve damage, ulcers, and cardiovascular problems such as atherosclerosis. 

There are several causes of diabetic endothelial dysfunction. One cause involves high levels of homocysteine, which leave blood vessel tissues vulnerable to oxidative stress. High homocysteine levels are a significant risk factor for diabetes, so sometimes blood vessel damage precedes a diagnosis of Type 2 diabetes or prediabetes. Healthcare professionals believe that by the time someone is diagnosed with diabetes, blood vessel damage has already started.

The most common complication of a person with diabetes blood vessel damage is peripheral diabetic neuropathy (nerve damage in the extremities). Decreased blood flow due to blood vessel damage starves nerves of needed oxygen and nutrients. This makes nerves less able to transmit signals, resulting in tingling or numbness. 

About 50% of people with diabetes experience some form of nerve pain, tingling, or numbness, usually in their hands or feet. 

Metanx contains vitamins B6, B9, and B12. All three of these vitamins reduce homocysteine levels, helping to protect blood vessels from damage. Vitamin B9 is also vital for cell growth, so it helps damaged nerves recover. The powdered algae in Metanx is rich in omega-3 fatty acids, which help prevent cardiovascular problems and have antioxidant effects.

Metanx is intended as a long-term treatment. It is only part of the dietary management of diabetes. Patients will still need standard antidiabetic treatments to control blood sugar. 

• Standard Metanx dosage for adults: Two capsules taken once daily or one capsule taken twice daily by mouth

Metanx dosage for diabetic ulcer

Diabetic ulcers are a severe complication of long-term diabetes. They are open foot sores caused by nerve damage, blood vessel damage, and infection. They are fairly common: about 15% of people with diabetes will get a diabetic foot ulcer. 

Diabetic ulcers are one of the most common reasons for hospitalizing people with diabetes. Even with hospitalization, they can take weeks to heal. 

The standard treatments for diabetic ulcers do not involve drugs except for antibiotics. The treatments range from simple wound care to amputation. About 14% to 24% of people with a diabetic foot ulcer will have their foot amputated due to complications or bone infection.

Healthcare providers prescribe Metanx to diabetic patients with diabetic ulcers due to endothelial dysfunction, high homocysteine levels (hyperhomocysteinemia), or both. Dosages are the same as for diabetic neuropathy.

• Standard Metanx dosage for adults: Two capsules taken once daily or one capsule taken twice daily by mouth

Metanx dosage for children

Metanx is marketed for adult use and does not have pediatric dosages.

Metanx dosage restrictions

Metanx does not require dosage modifications in people with kidney or liver problems, or any other medical condition. 

How to take Metanx

Metanx is a high-dose vitamin B supplement. Take doses exactly as instructed:

• Please read the drug information sheet that comes with this medicine.

• Take two capsules daily.

• Both capsules can be taken at the same time or divided into two doses. If the prescriber specifies one way or the other, follow those instructions.

• Swallow each capsule with a drink of water. 

• Store Metanx capsules at room temperature protected from heat, light, and moisture.

Metanx dosage FAQs

How long does it take Metanx to work?

It will take two to three months of taking daily doses before the effects can be felt. The first signs may be tingling or pain in areas that had gone numb. This is a sign that the supplement is working and that nerves are recovering. It will take longer for the tingling or pain to go away and be replaced by normal sensations. 

How long does Metanx stay in your system?

The half-lives of vitamin B6, vitamin B9, and vitamin B12 are measured in weeks or months. The blood levels of these vitamins have half-lives of a few days. 

What happens if I miss a dose of Metanx?

Take a missed dose when remembered. Don’t take more than two capsules a day.

How long can you take Metanx?

Metanx is a long-term supplement that can be taken for months or years.

How do I stop taking Metanx?

Metanx can be stopped at any time without causing withdrawal symptoms. Before stopping Metanx, ask the prescriber for medical advice.

Patients, their caregivers, or the prescriber may discontinue Metanx treatment if the supplement causes an allergic reaction or symptoms of a chronic overdose. 

What is the maximum dosage for Metanx?

The manufacturer has not specified a maximum dosage. However, Metanx is a high-dose vitamin B supplement that might cause problems if overdosed for a long time. Exceeding the prescribed dosage doesn’t confer any additional benefits.

Can you overdose on Metanx?

It’s difficult to overdose on B vitamins unless someone takes very high doses for a long time. If there are concerns about an overdose, call a poison control center or healthcare provider.

What interacts with Metanx?

There are very few drug interactions with vitamin B6, B9, or B12. 

Some prescription drugs block folate (B9), such as the anticonvulsant phenytoin and cancer drugs called folate inhibitors, so these drugs will decrease the therapeutic benefits of Metanx. 

There are no serious drug interactions with vitamin B6 or vitamin B12.

What happens when you mix Metanx and alcohol?

People taking Metanx should not drink alcohol. It can interfere with the body’s absorption of vitamin B12. Most importantly, alcohol increases blood levels of homocysteine, one of the causes of blood vessel damage in diabetic patients.

Ask a doctor how much alcohol is allowed, if at all. Follow the doctor’s advice.

Is it safe to take Metanx during pregnancy?

Pregnant women should ask for medical advice from a gynecologist or obstetrician before taking Metanx.

The B vitamins in Metanx are critical to a fetus’s development and are all commonly found in prenatal vitamins but at much lower doses. If pregnant, follow the doctor’s advice about the maximum amount of these vitamins that should be taken daily.

Is it safe to take Metanx while breastfeeding?

Ask a doctor. Although the B vitamins in Metanx are beneficial while breastfeeding, they exceed the maximum daily doses recommended for women nursing an infant.

What are the side effects of Metanx?

The most common side effects of taking high doses of vitamin B6, B9, or B12 include:

• Mild transient diarrhea

• Nausea

• Abdominal discomfort

• Upset stomach

• Loss of appetite

• Headache

• Somnolence

• Acne

• Skin reactions

• Mild rash

What are the serious side effects of Metanx?

Serious adverse reactions are rare and limited to allergic reactions. 

Taking too much vitamin B6 can cause peripheral nerve problems such as paresthesias (tingling or strange sensations).

Who should not take Metanx?

Metanx’s only contraindications are known allergies to Metanx or its ingredients. However, people who are showing signs of vitamin B6, B9, or B12 poisoning should stop taking high doses of these vitamins.

What type of folate is in Metanx?

Metanx contains L-methylfolate calcium, the same active ingredient in brand-name Metafolin. Methylfolate is the active form of folate. Unlike folic acid, the ingredient found in most B9 vitamins, methylfolate does not need to be converted by the body into an active form. It begins working as soon as it’s absorbed into the body.

Is Metanx FDA approved?

No. The FDA does not regulate medical foods in the same way it regulates drugs. It only regulates health claims to ensure they are not false or misleading.

Sources

• Diabetic foot ulcer: a comprehensive review of pathophysiology and management modalities, World Journal of Clinical Cases

• Endothelial dysfunction in vascular complications of diabetes: a comprehensive review of mechanisms and implications, Frontiers in Endocrinology

• Folate fact sheet for health professionals, National Institutes of Health (NIH)

• Metanx, AlfaSigma USA, Inc.

• Metanx alleviates multiple manifestations of peripheral neuropathy and increases intraepidermal nerve fiber density in Zucker diabetic fatty rats, Diabetes

• Metanx capsules, AlfaSigma USA, Inc.

• Vitamin B6 fact sheet for health professionals, National Institutes of Health (NIH)

• Vitamin B12 fact sheet for health professionals, National Institutes of Health (NIH)