Niacin
Niacin Medication Information:
Niacin medication comes in several different strengths; click on the strength you need to view prices from pharmacies competing to earn your business.
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Niacin 500 mg
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Niacin is a generic medication for the drug Niaspan ER:
Niacin medication comes in several different strengths; click on the strength you need to view prices from pharmacies competing to earn your business.
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Niacin 250 mg
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Pharmacology
Pharmacokinetics
Niacin and niacinamide are readily absorbed from the gastrointestinal tract.
When taken in physiologic doses niacin is metabolized in the liver to niacinamide. When therapeutic doses are taken, only a portion is converted to niacinamide. The remainder is eventually excreted unchanged in the urine. Niacinamide is widely distributed in the body and is further metabolized in the liver before being excreted in the urine.
Dosage and Administration
To prevent deficiency, adequate dietary intake is preferred over supplementation whenever possible. Food sources include meat, poultry, fish (e.g., cod, halibut, salmon), dairy products (e.g., milk), eggs, whole grains, enriched flour and cereals.
Dosage of niacin and niacinamide must be carefully adjusted according to the patient's response and tolerance (see Table 2).
Table 2: Niacin/Niacinamide
Dose in Adult Patients
| Indication | Drug | Dose | Clinical Comment |
|---|---|---|---|
| Pellagra | Niacin/ Niacinamide | 300–500 mg po daily in divided doses; maximum daily dose is 500 mg. Children: 100–300 mg daily in divided doses. | In the treatment and prevention of pellagra, either niacin or niacinamide can be administered. |
| Dyslipidemia | Niacin, immediate release | Initial dose: 50 mg po TID. May double the dose q5days to 1.5–2.0 g/day. If tolerated, maximum daily dose is 4 g. | Starting at a low dose and titrating up slowly may reduce potential adverse reactions and achieve treatment goals by improving adherence to the regimen. Cholesterol and triglyceride concentrations should be determined prior to initiation of therapy and regularly during treatment. Monitor blood glucose, uric acid and liver transaminases at baseline and every 6 to 8 weeks during dose titration, then periodically thereafter. Administration of doses on a full stomach may reduce gastrointestinal distress. Flushing abates with time (see Adverse Reactions) as tachyphylaxis occurs. |
| Niacin, extended release | Initial dose: 500 mg po HS after a low fat snack for 4 weeks. May ↑ by 500 mg q4weeks to a maximum daily dose of 2000 mg po HS, if required. | Bedtime dosing minimizes flushing during the day. |
Dosage in Renal Impairment: Dose adjustment is recommended for niacin (see Table 3), but is not required for niacinamide.
Indications
Niacin and niacinamide are used in the prevention and treatment of pellagra.
Niacin is used as an adjunct to therapeutic lifestyle changes (e.g., diet, weight control, physical activity) for the reduction of elevated total cholesterol, LDL-C and TG levels and to increase HDL-C levels in patients with primary hypercholesterolemia, mixed dyslipidemia (Fredickson Type IIa and IIb) and hypertriglyceridemia (Fredickson Type IV and V). It may be used alone or in combination with other agents for additive effects. Canadian guidelines for the diagnosis and treatment of dyslipidemia have been published [Can J Cardiol 2006;22(11):913-27].
Niacinamide is not effective in the management of dyslipidemia and should not be used as a substitute.
Adverse Reactions
Gastrointestinal
abdominal pain, anorexia, constipation, flatulence, heartburn, activation of peptic ulcers and or peptic ulceration.
Musculoskeletal
myopathy, myositis, rhabdomyolysis (see Warnings and Precautions).
Neurologic
paresthesia.
Endocrine and Metabolism
decreased glucose tolerance, hyperuricemia, gout.
Central Nervous System
asthenia, dizziness, fatigue, insomnia, migraine.
Dermatologic
acanthosis nigricans, dry skin, hyperpigmentation, urticaria, sweating.
Ophthalmic
blurred vision, proptosis.
Adverse Drug Reactions Associated with Niacinamide
Niacinamide lacks vasodilating effects but is not effective in the management of dyslipidemia. Parenteral solutions of B complex vitamins containing niacinamide may cause flushing, itching or burning of the skin in patients susceptible to the effects of niacinamide. Niacinamide has also caused hyperhidrosis, nausea and abdominal cramps. Abnormal liver function test results have been reported.
Niacin
Adverse Drug Reactions with Incidence ≥1%
| Body System | Effect (estimated % incidence) | Clinical Comment |
|---|---|---|
| Cardiovascular | Flushing (90) | Flushing starts in the face and is accompanied by an intense feeling of warmth and itching. It may spread to the arms and chest and occasionally down to the legs and feet. Flushing may be accompanied by burning, stinging or tingling sensations, increase in skin temperature, gastrointestinal symptoms, pruritus and hypotension. Following oral administration, niacin-induced vasodilation occurs within 20 min and may persist for 20 to 60 min. The frequency and severity of flushing usually subsides with continued therapy. Administration of reduced doses or on a full stomach may decrease flushing. If not contraindicated, pretreatment with a nonsteroidal prostaglandin inhibitor (e.g., ASA) may reduce flushing. Less flushing episodes are associated with Niaspan, an extended-release formulation. Avoid concomitant alcohol, spicy foods, hot beverages or hot showers. |
| Central Nervous System | Headache (7) | |
| Dermatologic | Pruritus and rash (12) | |
| Gastrointestinal | Diarrhea (10), nausea (5), vomiting (5) | |
| Hepatic | Increased serum aminotransferase concentrations (1–50) | Hepatotoxicity has been reported more frequently with sustained-release formulations. It is usually dose related and reversible (see Warnings and Precautions). |
Adverse Drug Reactions Associated with Niacin (incidence unknown)
Cardiovascular
arrhythmias, edema, hypotension, orthostasis, vasovagal attacks.
Warnings and Precautions
Drug Interactions
Due to potentiation of hypotensive effect, postural hypotension may occur when niacin is administered with vasoactive drugs or ganglionic blocking agents.
Although sometimes used in combination, there have been isolated reports of rhabdomyolysis in patients taking niacin and lovastatin. A causal relationship with niacin has not been established. It is not known if there is an interaction with other HMG-CoA reductase inhibitors. Patients should be advised to report unexplained muscle pain, tenderness or weakness to their physician.
Because niacin can cause hyperglycemia, dosage adjustment of insulin or oral antihyperglycemic therapy may be required in diabetic patients.
Niacinamide has been reported to increase the blood levels of primidone and carbamazepine when taken concurrently.
Hepatic/Biliary/Pancreatic
Patients with gallbladder disease, history of jaundice or liver disease should be monitored closely while on niacin or niacinamide. Liver function tests (LFTs) should be conducted at baseline, and every 6 to 12 weeks during the first year, then periodically thereafter. If there are persistent unexplained elevations in serum transaminases more than 3 times the upper limit of normal or if the LFTs are associated with fever, nausea and/or malaise, therapy should be discontinued.
Endocrine and Metabolism
Mean changes in fasting blood glucose levels in well-controlled clinical trials were generally transient and modest. In patients with diabetes, an adjustment or change in diet and/or hypoglycemic treatment may be necessary for blood glucose control. Patients with impaired fasting glucose may require initiation of hypoglycemic treatment if they develop diabetes. Periodic monitoring of blood glucose concentration during niacin or niacinamide therapy is advised especially in the early phase of treatment.
Hyperuricemia may occur during niacin treatment and in general, once it occurs, it may remain during the duration of the treatment. Periodic monitoring of uric acid is advised. Niacin must be used with caution in patients predisposed to gout (see Contraindications).
Special Populations
Musculoskeletal
A small number of cases of myopathy with niacin monotherapy have been reported. Myopathy and rhabdomyolysis have also been reported with concurrent statin therapy. The true incidence of muscle side effects is unknown.
Drug-Laboratory Interactions
Niacin may cause false elevation in fluorometric determinations of urinary catecholamines and false-positive results may be obtained for urinary glucose when Benedict's reagent is used. Niacin has also been reported to cause false-positive results for blood bilirubin tests.
Pregnant Women
Niacin and probably niacinamide are compatible with pregnancy when the recommended daily allowance is used; however, safety of niacin, used at higher doses in lowering elevated serum cholesterol in pregnancy, has not been established. Fetal abnormalities have not been reported. Animal reproduction or teratology studies have not been conducted and thus it is unknown if fetal harm can occur using niacin at doses used for lipid disorders.
Nursing Women
Niacin and niacinamide distribute into breast milk. Problems have not been reported with intake of normal daily requirements, but there is no information pertaining to higher doses used in the treatment of dyslipidemia.
Contraindications
Patients with a known hypersensitivity to niacin or niacinamide or to any ingredient in the formulation or component of the container.
Patients with active liver disease, peptic ulcer disease, hyperuricemia with a history of gouty arthritis or uncontrolled hyperglycemia.
Niacin specifically is contraindicated in patients with severe hypotension.
Overdose
For management of a suspected drug overdose, CPhA recommends that you contact your regional Poison Control Centre. See the eCPS Directories section for a list of Poison Control Centres.
