Niacin

INTRODUCTION

Indications

Treatment and prevention of niacin deficiency (pellagra). Adjunctive therapy in certain hyperlipidemias (niacin only).

Action

Required as coenzymes (for lipid metabolism, glycogenolysis, and tissue respiration). Large doses decrease lipoprotein and triglyceride synthesis by inhibiting the release of free fatty acids from adipose tissue and decreasing hepatic lipoprotein synthesis (niacin only). Cause peripheral vasodilation in large doses (niacin only). Therapeutic Effects: Decreased blood lipids (niacin only). Supplementation in deficiency states.

Adverse Reactions/Side Effects

Adverse reactions and side effects refer to IV administration or doses used to treat hyperlipidemias

CNS: nervousness, panic. EENT: blurred vision, loss of central vision, proptosis, toxic amblyopia. CV: orthostatic hypotension. GI: HEPATOTOXICITY (ER ORAL FORM ONLY), GI upset, bloating, diarrhea, dry mouth, flatulence, heartburn, hunger pains, nausea, peptic ulceration. Derm: flushing of the face and neck, pruritus, burning, dry skin, hyperpigmentation, increased sebaceous gland activity, rashes, stinging or tingling of skin. Metab: glycosuria, hyperglycemia, hyperuricemia.

PHYSICAL THERAPY IMPLICATIONS

Examination and Evaluation

• Be alert for signs of hepatotoxicity, including anorexia, abdominal pain, severe nausea and vomiting, yellow skin or eyes, fever, sore throat, malaise, weakness, facial edema, lethargy, and unusual bleeding or bruising. Report these signs to the physician immediately.

• Assess any muscle pain, tenderness, or weakness, especially if niacin is used with other lipid-lowering drugs (statins, fibric acids). Advise patient that these symptoms may represent drug-induced myopathy, and that myopathy can progress to severe muscle damage (rhabdomyolysis). Report any unexplained musculoskeletal symptoms to the physician immediately, and suspend exercise and gait training until these symptoms can be evaluated.

• Assess blood pressure (BP) when patient assumes a more upright position (lying to standing, sitting to standing, lying to sitting). Document orthostatic hypotension and contact physician when systolic BP falls >20 mm Hg, or diastolic BP falls >10 mm Hg.

• Report signs of CNS toxicity including nervousness, panic attacks, or vision disturbances.

• Monitor any rash or other skin reactions (burning/itching skin, dryness, increased pigmentation). Report severe or unexpected skin reactions to the physician.

Interventions

• In patients with drug-induced myopathy, implement gradual strengthening and other therapeutic exercises to facilitate recovery from muscle pain and weakness. Use caution during early stages to avoid fatigue of affected muscles, and implement assistive devices (walker, cane, crutches) as needed to prevent falls and assist mobility. Increase exercise intensity as tolerated; recovery from myopathy typically takes 4–6 wk, but can be longer in older patients or people with comorbidities.

• Design and implement aerobic exercise and endurance training programs ...