Slo-Niacin Side Effects

Generic Name: niacin

Please note - some side effects for Slo-Niacin may not be reported. Always consult your doctor or healthcare specialist for medical advice. You may also report side effects to the FDA at http://www.fda.gov/medwatch/ or 1-800-FDA-1088 (1-800-332-1088).

Side Effects of Slo-Niacin - for the Consumer

Slo-Niacin Controlled-Release Capsules

All medicines may cause side effects, but many people have no, or minor, side effects. Check with your doctor if any of these most COMMON side effects persist or become bothersome when using Slo-Niacin Controlled-Release Capsules:

Stomach upset; temporary skin redness, tingling or feelings of warmth (flushing).

Severe allergic reactions (rash; hives; itching; difficulty breathing; tightness in the chest; swelling of the mouth, face, lips, or tongue); black, tarry, or bloody stools; changes in vision; cloudy or blurred vision; decrease in urine or dark-colored urine; fast or irregular heartbeat; flu-like symptoms (nausea, vomiting, "not well" feeling); loss of appetite; muscle weakness, swelling, tenderness, or pain; numbness or persistent tingling of the skin; swelling of the hands, legs, or feet; vomit that looks like coffee grounds; yellowing of the skin or eyes.

Side Effects by Body System

General

Generally, the incidences of hepatic and gastrointestinal side effects have been significantly greater with use of timed release niacin when compared to an immediate release form, however, the incidence of cutaneous flushing has been significantly less.

Dermatologic

Dermatologic flushing (facial and whole body) and pruritus as a result of stimulation and release of prostaglandins by niacin have been major drawbacks of this drug. These symptoms have occurred in up to 78% of patients and usually resolved after 2 weeks of continued therapy. Flushing can be minimized with use of an extended release form of the drug, gradual dosage titration (over 2 to 3 months), and by administering the dosage during or within 30 minutes after meals. Aspirin (325 mg), if not otherwise contraindicated, taken within 30 minutes of niacin ingestion and avoidance of hot beverages and alcohol which can aggravate flushing by causing peripheral vasodilation may be recommended to reduce flushing.

In addition, maculopapular rash, urticaria, dry skin, and sweating have been associated with niacin use. Rare cases of hyperpigmentation and acanthosis nigricans have also been reported.

Hepatic

Hepatic side effects including hepatotoxicity and hepatitis have been reported in 2% to 3% patients who have taken larger doses (3 grams or more daily) or who have used timed release preparations. Hepatotoxicity usually reverses within one week after drug discontinuation, but sometimes can be avoided with dosage reductions or switching to crystalline niacin (if hepatotoxicity developed while using a timed release preparation). Clinical monitoring of patient response and tolerance, including laboratory evaluation of liver function tests is generally recommended.

Dose-related increases in aspartate aminotransferase and alkaline phosphatase have been associated with dosage increases greater than 2.5 grams over 1 month. Computerized tomography has revealed changes consistent with focal fatty liver in some cases. Although these changes usually resolve with dose reduction, continued routine monitoring of liver function tests is recommended. Rare cases of fulminant, even fatal, hepatic failure have been reported.

In one retrospective analysis of 969 predominantly elderly male veterans treated for dyslipoproteinemia with controlled release niacin (average dose 3.1 grams/day), the incidences of possible and probable hepatotoxicity (biochemical criteria) were 2.2% and 4.7%, respectively. Predisposing risk factors included high dose, alcohol use, preexisting liver disease, and concurrent oral sulfonylurea use. The incidence of hepatotoxicity was significantly less among patients who were taking an average daily dose of 2.1 grams.

Gastrointestinal

Gastrointestinal disturbances have included exacerbation of peptic ulcer disease, eructation, nausea, vomiting, diarrhea, flatulence, and dyspepsia. Persistent fatigue, nausea or anorexia may be a sign of hepatotoxicity.

Metabolic

Nicotinic acid competes with uric acid for excretion by the kidneys. Hyperuricemia associated with niacin appears to be more common in men.

Metabolic changes associated with niacin have included hyperuricemia and hyperglycemia. Clinical monitoring of patient response and tolerance, including laboratory evaluations of serum uric acid and blood glucose levels, is recommended in patients with a history of gout or diabetes mellitus.

Cardiovascular

Cardiovascular side effects generally have been rare. Transient tachycardia, palpitations, atrial fibrillation, orthostasis, syncope, hypotension, and dizziness have been reported. The Coronary Drug Project (1975) reported a significant increase in cardiac arrhythmias associated with the use of niacin; some experts consider preexisting arrhythmias or angina pectoris contraindications to its use.

Niacin has been shown to increase plasma homocysteine levels. Homocysteine is an independent risk factor for arterial occlusive disease. Clinical implications of these increases and the influence of folic acid supplementation as a means to decrease homocysteine levels remain to be determined.

Nervous system

Nervous system side effects have included rare reports of paresthesias, nervousness, dizziness, headache, fatigue, and insomnia.

Hematologic

Hematologic side effects including rare hematologic coagulopathies associated with niacin-induced elevations of liver function tests have occurred.

Genitourinary

Genitourinary complaints of decreased sexual function have been reported in up to 3% and 22% of male patients who have taken unmodified and timed release niacin, respectively.

Endocrine

Endocrine side effects including rare incidences of altered thyroid function tests have been reported. Changes appeared to be due to decreased thyroid binding capacity and concentration of thyroid binding globulin.

Ocular

Niacin appears to cause a reversible toxic cystoid maculopathy in approximately 0.7% of patients taking at least 1.5 grams daily. The maculopathy typically has been reversible upon discontinuation of therapy.

Ocular side effects have included amblyopia, sicca syndromes, blurred vision, eyelid edema, and macular edema.

Musculoskeletal

Musculoskeletal side effects associated with niacin have included myalgia, myasthenia, myopathy, and leg cramps. Creatine kinase increase was reported post-marketing in the sustained release product.

Hypersensitivity

Hypersensitivity effects associated with niacin have included rash, generalized edema, facial edema, and peripheral edema.

Respiratory

Respiratory side effects have included dyspnea.

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