Nizatidine dosing

HISTAMINE H2 ANTAGONISTS. The nurse administers ranitidine and oral cimetidine before or with meals and at bedtime Nizatidine and famotidine are given at bedtime or, if twice-a-day dosing is prescribed, in the morning and at bedtime. These drugp are usually given concurrently with an antacid to relieve the pain. In certain situations or disorders, cimetidine and ranitidine may also be given by intermittent IV infusion or direct IV injection. 

A nurse is to administer nizatidine once daily. When would the nurse most correctly administer the once-daily dose of nizatidine ... 

Nwokolo CU, Smith JT, Gavey C, Sawyerr A, Pounder RE Tolerance during 29 days of conventional dosing with cimetidine, nizatidine, famotidine or ranitidine. Aliment Pharmacol Ther 1990 4(suppl 1) 29—45. 

Histamine-2 antagonists (cimetidine, famotidine, nizatidine, ranitidine) may be used in low doses to manage simple nausea and vomiting associated with heartburn or gastroesophageal reflux. 

Antagonists. Most of the so-called Hi-antihistamines also block other receptors, including M-cholinoceptors and D-receptors. Hi-antihistamines are used for the symptomatic relief of allergies (e.g., bamipine, chlorpheniramine, clemastine, dimethindene, mebhydroline pheniramine) as antiemetics (meclizine, dimenhydrinate, p. 330), as over-the-counter hypnotics (e.g., diphenhydramine, p. 222). Promethazine represents the transition to the neuroleptic phenothiazines (p. 236). Unwanted effects of most Hi-antihistamines are lassitude (impaired driving skills) and atropine-like reactions (e.g., dry mouth, constipation). At the usual therapeutic doses, astemizole, cetrizine, fexofenadine, and loratidine are practically devoid of sedative and anticholinergic effects. Hj-antihistamines (cimetidine, ranitidine, famotidine, nizatidine) inhibit gastric acid secretion, and thus are useful in the treatment of peptic ulcers. 

Deravirdine (Rescnptor) [Antiretroviral/NNRTI] Uses HIV Infxn Action Nonnucleoside RT inhibitor Dose 400 mg PO tid Caution [C, ] CDC recommends HIV-infected mothers not to breast-feed (transmission risk) w/ renal/hepatic impair Contra Use w/ drugs dependent on CYP3A for clearance (Table VI-8) Disp Tabs SE Fat redistribution, immune reconstitution synd, HA, fatigue, rash, T transaminases, N/V/D Interactions T Effects W/ fluoxetine T effects OF benzodiazepines, cisapride, clarithromycin, dapsone, ergotamine, indinavir, lovastatin, midazolam, nifedipine, quinidine, ritonavir, simvastatin, terfena-dine, triazolam, warfarin effects W/ antacids, barbiturates, carbamazepine, cimetidine, famotidine, lansoprazole, nizatidine, phenobarbital, phenytoin, ranitidine, rifabutin, rifampin effects OF didanosine EMS Use of benzodiazepines and CCBs should be avoided may cause a widespread rash located on upper body and arms OD May cause an extension of nl SEs symptomatic and supportive Deferasirox (Exjade) [Iron Chelator] Uses Chronic iron overload d/t transfusion in pts >2 y Action Oral iron chelator Dose Initial 20 mg/kg... 

Histamine H2-receptor antagonists are well absorbed orally, although concurrent antacid therapy may reduce bioavailability by up to 30%. They are widely distributed in the body, crossing the blood-brain barrier and the placenta. Cimetidine, ranitidine and famotidine are extensively metabolised in the liver, and about one-third excreted unchanged in urine, while only one-third of nizatidine is metabolised (Table 11.1). Elimination half-life is increased up to tenfold in renal failure, and doses must be adjusted. 

Histamine H2-receptor antagonists are the mainstay of prevention of Mendelson s syndrome at present. Probably the best protection is afforded by a combination of H2-receptor blockade by ranitidine and a single oral dose of sodium citrate or bicarbonate. Because of its longer duration of action, and relative lack of enzyme inhibition, ranitidine is preferred to cimetidine for this purpose, although there is a latent period of 1-2 hours before it takes effect. Famotidine and nizatidine are probably equally effective in blocking acid secretion. 

CIMETIDINE FAMOTIDINE NIZATIDINE, RANITIDINE BRONCHODILATORS -THEOPHYLLINE t efficacy and adverse effects, including seizures. There is conflicting information associated with ranitidine, famotidine and nizatidine Inhibition of metabolism via CYP1A2, cimetidine being the best known inhibitor Use alternative acid suppression, e.g. a proton pump inhibitor (not omeprazole or lansoprazole) or monitor closely considerable patient variation. Check levels on day 3 and then at 1 week. A 30-50% i dose of theophylline may be required. For doses <400 mg/day, the interaction may not be clinically significant... 

The modes of action, uses and therapeutic efficacy of these histamine receptor antagonists are essentially those of cimetidine. Differences from cimetidine lie chiefly in dose and profile of unwanted effects. Ranitidine (t / 2 h) is 50%, famotidine (tl 3 h) is 25% and nizatidine (t / 1 h) is 10% metabolised, in each case the remainder being excreted unchanged by the kidney. 

A. Oassification and Prototypes Four H, blockers are available cimetidine is the prototype. Ranitidine, famotidine, and nizatidine differ only in being slightly less toxic than cimetidine. These drugs do not resemble H, blockers structurally. They are orally active, with half-lives of 1-3 hours. Because they are relatively nontoxic, they can be given in large doses, so that the duration of action of a single dose may be 12-24 hours. 

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