Niacin (nicotinic acid)
Indications
Niacin (nicotinic acid) is used for:
Hyperlipidaemias, Nicotinic acid deficiency, Ischaemic events
Adult Dose
Oral
Treatment and prophylaxis of nicotinic acid deficiency
Adult: For treatment of pellagra: 300-500 mg daily in divided doses. For management of Hartnup disease: 50-200 mg daily.
Hyperlipidaemias
Adult: Initially, 250 mg once daily in the evening. Increase dose every 4-7 days until desired LDL cholesterol and/or triglyceride level is achieved or dose of 1.5-2 g/day is reached. If hyperlipidaemia is not adequately controlled after 2 mth w/ this dose, it can be increased at 2- to 4-wk intervals to 1 g tid. Max: 6 g daily.
As extended-release tab: Initially, 500 mg/day PO at bedtime initially; dose adjusted every 4 weeks on basis of effect and tolerance to therapeutic dose of 1-2 g once daily; not to exceed 1-2 g/day
Vasodilation
Adult: 100-150 mg 3-5 times daily. As extended-release tab: 300-400 mg 12 hrly.
Child Dose
Oral
Treatment and prophylaxis of nicotinic acid deficiency
Child: For treatment of pellagra: 100-300 mg daily in divided doses.
Renal Dose
Administration
Should be taken with food. Take at bedtime after a low-fat snack.
Contra Indications
Niacin is contraindicated in patients with a known hypersensitivity to Niacin or any component of this medication, significant or unexplained hepatic dysfunction, active peptic ulcer disease or arterial bleeding.
Precautions
Patient w/ unstable angina, acute MI, CHD, DM, gout, history of peptic ulceration. Patient who consume large amount of alcohol. Patient undergoing surgery. Renal or hepatic impairment. Pregnancy and lactation. Monitoring Parameters Monitor LFTs and blood glucose frequently.
Pregnancy-Lactation
Interactions
Increased risk of myopathy and rhabdomyolysis w/ concomitant HMG-CoA reductase inhibitors. Reduced bioavailability w/ colestyramine or colestipol. Decreased metabolic clearance w/ aspirin. May potentiate effects of ganglionic blocking agents and vasoactive drugs resulting in postural hypotension.
Side Effects
Side effects of Niacin (nicotinic acid) :
Flushing, sensation of heat, faintness, pounding in the head, tingling, itching, headache, dizziness, tachycardia, palpitations, dyspnoea, sweating, chills, oedema; dryness of skin, pruritus, hyperpigmentation, rash, cramps, cough, diarrhoea, nausea and vomiting, anorexia, activation of peptic ulcer, eye disorders including cystoid macular oedema and toxic amblyopia; decreased glucose tolerance, hyperglycaemia, hyperuricaemia; abnormal LFTs, jaundice; hypophosphataemia, reduced platelet counts, prolonged prothrombin time, arrhythmias, hypersensitivity reactions including angioedema; insomnia, myalgia and hypotension.
Mode of Action
Nicotinic acid is a derivative of vitamin B3 and is incorporated into coenzymes nicotinamide adenine dinucleotide (NAD) and nicotinamide adenine dinucleotide phosphate (NADP), which are involved in multiple cellular metabolic pathways. Nicotinic acid also reduces total serum cholesterol, LDL, VLDL, and triglycerides, and increases HDL cholesterol. It appears to decrease hepatic synthesis of VLDL, however, the exact mechanisms of nicotinic acid's antilipemic effects are unknown and are unrelated to its role as a vitamin.