Niacin or Vitamin B3 is a water-soluble vitamin. It is used to treat the following conditions:

• Dietary supplement:

  • It is used as a dietary supplement.

• Dyslipidemias:

  • It is used as a monotherapy or supplementary therapy to treat dyslipidemias (Fredrickson types IIa and IIb or primary hypercholesterolemia).

  • In individuals with a history of MI and hyperlipidemia, it is used to reduce the risk of recurrent MI.

  • It is employed to stop the progression of coronary artery disease or encourage its regression.

  • Adults at risk of pancreatitis can use it as an additional therapy for severe hypertriglyceridemia.

• Off Label Usage of Vitamin B3 in Adults:

  • It can be used as off label agent in pellagra

Niacin (Vitamin B3) Dose in Adults

• Niacin's two formulations—regular release and extended release—are not interchangeable.

Niacin dosage in the treatment of Dietary supplements (OTC labeling):

• It is given either 50 mg or 100 mg orally twice daily.

Niacin dosage in the treatment of Dyslipidemia:

• Regular release formulation (Niacor):

  • At first, 250 mg is administered orally once daily (with an evening meal)
  • To achieve the desired response or the first-level therapeutic dose, increase the dose frequency and/or dose every 4 to 7 days (1.5 to 2 g daily in 2 to 3 divided doses)
  • After two months, it may be increased at 2- to 4-week intervals up to three divided doses of 3 g each day.
  • The maximum dosage is 6 g divided into 3 doses each day.

• Sustained-release (or controlled release) formulations:

Slo-Niacin:

• • The typical dose is 250 to 750 mg taken once daily orally.
  • Taken either in the morning or at night, or as advised.
  • The patient should speak with a doctor before taking more than 500 mg per day.

• Extended-release formulation (Niaspan):

  • Initially, 500 mg is administered orally at bedtime for 4 weeks.
  • After 4 weeks of taking 1 g at bedtime, alter the dose based on response and tolerance.
  • Every four weeks, the daily dose may be increased by no more than 500 mg, up to a daily maximum of 2 g.
  • At bedtime, a maintenance dose of 1,000–2,000 mg is advised.

Off Label dosage in the treatment of Pellagra :

• Regular release formulation:

  • 50-100 mg taken orally 3-5 times per day are administered
  • The maximum daily dose is 500 mg.
  • Niacinamide has a better side effect profile, hence some doctors choose it for treatment.

Niacin (Vitamin B3) Dose in Children

Niacin dose in the treatment of Dyslipidemias:

• Children ≥10 years and Adolescents

  • Regular release:

    • Initially, three divided doses of 100 to 250 mg were taken orally with meals.
    • 10 mg/kg/day is the maximum initial daily dose.
    • If tolerated, it is raised every week by 100 mg/day or every two to three weeks by 250 mg/day.
    • Then, using laboratory testing, determine the effectiveness and side effects at 20 mg/kg/day or 1,000 mg/day (whichever is less)
    • Continually raise the dose as tolerated and as needed
    • At each 500 mg increment, reevaluate
    • Up to 2,250 mg per day have been administered daily.

  • Sustained-release:

    • 500 to 1,500 mg are taken orally each day.
    • Start with a little amount that is given once a day.
    • The initial dose of 10 mg/kg/day has not been surpassed.
    • Titrate every three to four weeks (in adults, doses are titrated every 4 weeks)

Niacin dosage in the treatment of Pellagra:

• Children and Adolescents:

  • There is a regular release. 50 to 300 mg orally, three times a day, in divided doses

  • The typical course of treatment lasts 3 to 4 weeks.

Dosing adjustment for toxicity:

• Children ≥10 years and Adolescents:
  • In a trial involving children, the treatment with niacin was discontinued due to hepatotoxicity, abdominal pain, headaches, and/or severe flushing (for example, a rise in transaminases that was either prolonged or accompanied by symptoms of nausea, fever, and/or malaise).

Niacin Pregnancy Risk Factor C

• Water-soluble vitamins that can cross the placenta are conceivable
• Niacin can be administered to supplement pregnant women's nutritional needs.
• Animal reproduction has not been the subject of studies.
• Niacin should be stopped if a woman becomes pregnant while taking it for primary hypercholesterolemia.
• The advantages and hazards of continuing to use niacin if a woman falls pregnant while taking it for hypertriglyceridemia should be evaluated on an individual basis.
• Niacin may be detrimental to the developing foetus in lipid-lowering dosages, however, this is uncertain.

Use of Niacin (Vitamin B3) during breastfeeding

• Breast milk contains Niacin.
• If used as a dietary supplement to niacin, breastfeeding women might have higher niacin needs than non-breastfeeding mothers.
• The manufacturer warns that serious adverse reactions could occur in breastfeeding infants. They advise against discontinuing breastfeeding and recommending discontinuing the drug.

Niacin dose in Renal Disease:

• There are no dosage adjustments given in the manufacturer's labeling;
• use with caution.

Niacin (Vitamin B3) dose in Liver disease:

• Not recommended for people who have active liver disease, substantial or unexplained hepatic dysfunction, or chronic transaminase increases.
• The manufacturer's labelling does not mention dosage modifications (has not been studied).

Rare Side effects of Niacin (Vitamin B3):

• Dermatologic:

  • Diaphoresis
  • Hyperpigmentation
  • Maculopapular Rash
  • Pruritus
  • Acanthosis Nigricans
  • Urticaria

  • Xeroderma

  • Burning Sensation Of Skin
  • Skin Discoloration
  • Skin Rash
•  

• Respiratory:

  • Cough
  • Dyspnea

• Cardiovascular:

  • Edema
  • Flushing
  • Hypotension
  • Orthostatic Hypotension
  • Palpitations
  • Atrial Fibrillation
  • Cardiac Arrhythmia
  • Tachycardia

• Endocrine & Metabolic:

  • Gout
  • Hyperuricemia
  • Increased Amylase
  • Decreased Glucose Tolerance
  • Decreased Serum Phosphate
  • Increased Lactate Dehydrogenase

• Central Nervous System:

  • Headache
  • Insomnia
  • Migraine
  • Chills
  • Paresthesia
  • Dizziness
  • Myasthenia
  • Nervousness
  • Pain

• Gastrointestinal:

• • Dyspepsia
  • Eructation
  • Flatulence
  • Abdominal Pain
  • Diarrhea
  • Nausea
  • Peptic Ulcer
  • Vomiting

• Hematologic & Oncologic:

  • Decreased Platelet Count
  • Prolonged Prothrombin Time

• Neuromuscular & Skeletal:

  • Myalgia
  • Myopathy (With Concurrent HMG-Coa Reductase Inhibitor)
  • Increased Creatine Phosphokinase
  • Leg Cramps
  • Weakness

• Hepatic:

  • Increased Serum Bilirubin
  • Increased Serum Transaminases (Dose-Related)
  • Hepatitis
  • Jaundice,

• Ophthalmic:

  • Blurred Vision
  • Cystoid Macular Edema
  • Toxic Amblyopia

Contraindication to Vitamin B3 Include:

• Liver transaminase increases that are persistent or undiagnosed and active hepatic disease

• An open stomach ulcer

• Hypersensitivity to niacinamide or any other formulation ingredient

• Arterial bleeding

Warnings and precautions

• Flushing/pruritus

  • Niacin can cause flushing and pruritus as side effects.

  • It may be lessened by gradually increasing the amount, taking it with food, avoiding alcoholic beverages, hot or spicy foods, and/or taking aspirin 30 minutes before the dose.

  • The manufacturer states that it can also be taken along with other NSAIDs.

  • When using extended-release products, flushing is drastically decreased.

  • To reduce flushing/pruritus, you can give immediate-release preparations in two to three divided doses.

  • You should cease the therapy if severe cutaneous problems continue.

• GI effects

  • By gradually increasing the dose and ingesting food along with it, GI distress might be lessened. 
    ​​​​​It is not advisable for anyone to take this medication if they have active peptic ulcer disease. 
    It can aggravate a peptic ulcer and induce GI pain, vomiting, and diarrhoea. 
    Patients who have had peptic ulcers before should exercise caution. 
    If you experience unexplained abdominal pain/weight gain or any other GI symptoms, it is worth stopping therapy.

• Hematologic effects

  • There may be dose-related increases in prothrombin times or declines in platelet count.

• Hepatotoxicity:

  • There have been occurrences of fulminant liver necrosis and severe hepatotoxicity.

  • At that time, sustained-release (modified release, timed-release) medications for niacin were substituted with immediate-release (crystalline) preparations at the same doses.

  •  

  • To achieve the desired response, patients should start with low doses (e.g. 500 mg of niacin extended-release at bedtime) and then increase their dosage.

  • Liver function tests should be performed on patients on lipid-lowering medications.

  • Stop taking the medication if hepatic Transaminase levels reach 3x ULN or remain elevated, especially if they are accompanied by symptoms like nausea, fever, and/or malaise.

• Diabetes:

  • It is linked to new-onset diabetes and worsening of glucose tolerance in patients who have preexisting diabetes.

  • Patients with diabetes should be cautious.

  • Keep an eye on glucose

  • Adjustment of diet or hypoglycemic therapy may be required.

  • If persistent hyperglycemia persists during therapy, you should stop.

• Hypophosphatemia

  • It has been shown to cause small, but statistically significant, reductions in phosphorus levels due to its use.

  • Patients at high risk of hypophosphatemia should be monitored for low levels of phosphorus.

• Hepatic impairment

  • Patients with a history of hepatic impairment should be cautious.

  • Monitor liver function tests

  • Contraindicated in patients with liver disease, persistent transaminase elevation, or active liver disease.

• Cardiovascular disease
  • Patients who have unstable angina and those who are experiencing an acute MI should exercise caution.
  • When given immediate-release (crystalline) niacin, patients with pre-existing cardiovascular disease were more likely to have atrial fibrillation than those who received a placebo.

  • If during treatment new-onset atrial fibrillation appears, discontinue taking the medication.

    .

• Gout
  • It can also lead to hyperuricemia.
  • Patients at risk for developing gout should exercise caution.

  • If acute gout appears while you're taking the medication, stop.

• Renal impairment

  • Renal impairment patients need to exercise caution.

Vitamin B3 (niacin): Drug Interaction

Monitor:

• Uric acid (if predisposed to gout)
• Blood glucose (in diabetic patients)
• Monitor liver function more frequently if a history of transaminase elevation with prior use
• If on concurrent HMG-CoA reductase inhibitor, might periodically check CPK and serum potassium
• Lipid profile
• Phosphorus (if predisposed to hypophosphatemia)
• Platelets (if on anticoagulants)
• PT (if on anticoagulants)
• Liver function tests pretreatment, every 6 to 12 weeks for the first year, then periodically (approximately every 6 months)

How to administer Vitamin B3?

• Administer while eating.
• Pre-medicate with aspirin 30 minutes before the dose to lessen flushing symptoms, and avoid consuming alcohol or hot or spicy meals or liquids at the same time as taking niacin.
• According to the manufacturer, additional NSAIDs may be used in order to prevent flushing.

• Niaspan:

  • After a low-fat snack and before going to bed.
  • Three of the 500 mg and two of the 750 mg strength tablets are not interchangeable, but two of the 500 mg and one of the 1,000 mg strength tablets are.
  • Start Niaspan following the suggested titration regimen when switching from the immediate-release tablet.
  • The dose needs to be changed if therapy is stopped for a long time.
  • Crushing, breaking, or chewing should not be done with long-acting formulations.
  • Slo-Niacin can be divided according to the score.
  • Avoid switching from immediate release to long-acting versions.

Mechanism of action of Niacin (Vitamin B3):

• The biotransformation of niacin (nicotinic acid) into nicotinamide results in nicotinamide (NAD+), which is further turned into nicotinamide (NADH), and coenzymes that are necessary for tissue metabolism, lipid metabolism, and glycogenolysis.
• Niacin's impact on plasma lipoproteins, when taken at lipid-lowering levels, is unknown.
• It might entail both an increase in lipoprotein lipase activity, which helps remove plasma chylomicron triglycerides and partial suppression of the release of free fatty acids from adipose cells.
• Additionally, niacin lowers triglycerides, total cholesterol, and apolipoprotein B (apo) B.
• Additionally, it raises HDL and other critical elements.

Absorption:

• The formulation for immediate release absorbs quickly and thoroughly.
• Food increases the amount of niacin ER absorption from niacin ER/lovastatin.

Protein binding: Less than 20% of it was attached to serum proteins.

Metabolism: It undergoes substantial first-pass metabolism and is transformed into nicotinic acid, nicotinamide adenine dinucleotide, and other metabolites. Metabolic pathways are saturable at dosages used to treat hyperlipidemia.

Time to peak, serum: Immediate release formulation: 30 - 60 minutes; extended-release formulation: 4 - 5 hours

Bioavailability: Studies on single doses show that only some Niaspan tablet strengths are interchangeable (ie, two 500 mg tablets are equivalent to one 1,000 mg tablet; however, three 500 mg tablets are not equivalent to two 750 mg tablets)

Half-life elimination: 20 - 48 minutes

Excretion: Urine 60% - 88% (unchanged drug [up to 12% recovered after multiple dosing] and metabolites) 

International Brands of Niacin (Vitamin B3):

• Slo-Niacin
• Niaspan FCT
• Niaspan [DSC]
• Niodan
• Acido Nicotinico
• Niacin-50
• Niaspan
• Nicangin
• Nicobid
• Nicoson
• Apo-Nicotinic Acid
• Atconiason
• Niacor
• Niaspan
• Acidum nicotinicum
• Exlip ER
• Niaspan LP
• Niaspanor
• Niacyn
• Niapid
• Nicotabs
• Nicotinic Acid
• Nyclin
• Pepevit
• Timaspan

Niacin (Vitamin B3) Brands in Pakistan:

No Brands Available in Pakistan.