Nifedipine side effects

The side effects of diltia2em therapy are less than those of verapamil or nifedipine therapy. Side effects occur in about 4% of the patients (1,98,99). 

Po adrninistered nifedipine is almost completely absorbed. The onset of action is 20 min and peak effects occur at 1—2 h. The principal route of elimination is through hepatic metaboHsm by oxidation to hydroxycarboxyHc acid and the corresponding lactone. These metaboHtes are pharmacologically inactive. Almost 70—80% of dmg is eliminated in the urine during the first 24 h. About 15% is excreted in the feces. The elimination half-life of nifedipine is about 1—2.5 h (1,98,99). Frequency of occurrence of side effects in patients is about 17% with about 5% requiring discontinuation of therapy (1,98,99). 

Nifedipine (Table 3) is a potent vasodilator that selectively dilates resistance vessels and has fewer effects on venous vessels. It does not cause reflex tachycardia during chronic therapy. Nifedipine is one of the first-line choices for black or elderly patients and patients having concomitant angina pectoris, diabetes, or peripheral vascular diseases. Nifedipine, sublingually, is also suitable for the treatment of hypertensive emergencies. Nifedipine does not impair sexual function or worsen blood Hpid profile. The side effects are flushing, headache, and dizziness. 

Diltiazem inhibits calcium influx via voltage-operated channels and therefore decreases intracellular calcium ion. This decreases smooth muscle tone. Diltiazem dilates both large and small arteries and also inhibits a-adrenoceptor activated calcium influx. It differs from verapamil and nifedipine by its use dependence. In order for the blockade to occur, the channels must be in the activated state. Diltiazem has no significant affinity for calmodulin. The side effects are headache, edema, and dizziness. 

Short-acting nifedipine may rarely cause an increase in the frequency, intensity, and duration of angina in association with acute hypotension. This effect may be obviated by using sustained-released formulations of nifedipine or other dihydropyridines. Other side effects of dihydropyridines include dizziness, flushing, headache, gingival hyperplasia, and peripheral edema. Side effects due to vasodilation such as dizziness, flushing, head-... 

Nifedipine is associated with fewer side effects than magnesium or ft-agonist therapy. Five to 10 mg nifedipine may be administered sublingually every 15 to 20 minutes for three doses. Once stabilized, 10 to 20 mg may be administered by mouth every 4 to 6 hours for preterm contractions. 

Co-codamol is a combination of paracetamol (nonnapioid analgesic) and codeine (opioid analgesic). One of the side-effects of opioids is constipation. Naprosyn is a proprietary (trade name) preparation of the non-steroidal antiinflammatory drug naproxen Adalat is a proprietary preparation of the calcium-channel blocker nifedipine Amoxil is a proprietary preparation of the beta-lactam amoxicillin and Dulco-lax is the brand name of the stimulant laxative bisacodyl. 

Diltiazem, a benzothiazepine, has a pharmacodynamic and side-effect profile that is intermediary between those of nifedipine and verapamil. Diltiazem is mostly used in the treatment of stable angina. It also displays antihypertensive activity, although it is not widely used in antihypertensive treatment. In certain countries diltiazem is used as an antiarrhyth-mic agent with the same type of applications as verapamil. 

Answer Nifedipine, unless formulated for slow, sustained release, is characterized by relatively rapid onset of vasodUatory effects. This man s side effects reflect the rapid and intense fall in blood pressure and consequent reflex increases in sympathetic tone. The increase in anginal episodes also is a result of drug-induced periodic increases in heart rate. 

Serious side effects are rare and result from improper use of these agents, as when intravenous verapamil (or diltiazem) is given to patients with sinus or atrioventricular nodal depression from drugs or disease, or nifedipine to patients with aortic stenosis. 

Pereira et al. (1993) evaluated postoperative pain relief and incidence of side-effects of the combination of epidural morphine (0.5 mg) and sublingual nifedipine (10 mg). In this double-blind, placebo-controlled study 36 women were submitted to elective operations (hysterectomy and colpoperineoplasty). The nifedipine-treated group showed a significant drop in blood pressure which was controlled by rehydration. The results indicate that epidural morphine-induced postoperative pain relief may be enhanced by systemic administration of nifedipine with easily controlled side-effects. 

Nifedipine [nye FED i peen] functions mainly as an arteriolar vasodilator. This drug has minimal effect on cardiac conduction or heart rate. Nifedipine is administered orally and has a short half-life (about 4 hours) requiring multiple dosing. The vasodilation effect of nifedipine is useful in the treatment of variant angina caused by spontaneous coronary spasm. Nifedipine can cause flushing, headache, hypotension, and peripheral edema as side effects of its vasodilation activity. The drug may cause reflex tachycardia if peripheral vasodilation is marked resulting in a substantial decrease in blood pressure. 

CALCIUM CHANNEL BLOCKERS TACROLIMUS Plasma concentrations of tacrolimus are t when given with diltiazem, felodipine or nifedipine however, they appear to protect renal function Uncertain, but presumed to be due to inhibition of CYP3A4-mediated tacrolimus metabolism Watch for side-effects of tacrolimus monitor ECG, blood count and renal and hepatic function... 

Single oral or sublingual dose of a calcium channel blocker (e.g., nifedipine) for urgent treatment of hypertension due to drug interaction or dietary tyramine Many side effects cannot be improved with an augmenting agent... 

DeWood MA, Wolbach RA. Randomized double-blind comparison of side effects of nicardipine and nifedipine in angina pectoris. The Nicardipine Investigators Group. Am Heart J 1990 119(2 Pt 2) 468-78. 

Terry RW. Nifedipine therapy in angina pectoris evaluation of safety and side effects. Am Heart J 1982 104(3) 681-9. 

Fattore L, Stablein M, Bredfeldt G, Semla T, Moran M, Doherty-Greenberg JM. Gingival hyperplasia a side effect of nifedipine and diltiazem. Spec Care Dentist 1991 ll(3) 107-9. 

While it is characteristically a side effect of hydantoin derivatives, it may occur during the administration of pheno-barbital, nifedipine, diltiazem and other medications. 

Heart block is a contraindication for the nondihydropyridines. The most common side effects are bradycardia and heart block (for the nondihydropyridines). Peripheral edema and headache are also common. Nondihydropyridines exacerbate bradycardic effects of /S-blockers, and verapamil raises digoxin serum concentrations by 70%. Diltiazem raises cyclosporine serum concentrations. Intravenous calcium salts inhibit the pharmacologic effect of CCBs. Generic formulations or similar products, but not necessarily generic equivalents to the original brand names, are available for verapamil, nifedipine, and diltiazem. 

The calcium channel blockers generally are considered seconder third-line options for preventive treatment when other drugs with established clinical benefit are ineffective or contraindicated. Verapamil is the most widely used calcium chaimel blocker for preventive treatment, but it provided only modest benefit in decreasing the frequency of attacks in two placebo-controlled studies." The therapeutic effect of verapamil may not be noted for up to 8 weeks after initiation of therapy. Side effects of verapamil may include constipation, hypotension, bradycardia, atrioventricular block, and exacerbation of congestive heart failure. Evaluations of nifedipine, nimodipine, diltiazem, and nicardipine have yielded equivocal results. ... 

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