Gastroesophageal reflux disease (GERD) is the most common GI condition encountered in the outpatient setting; it affects about 20% of people in the US.

Gastroesophageal reflux disease (GERD) is the most frequent GI condition encountered in the outpatient setting; it affects about 20% of the US population. Heartburn and regurgitation are the classic symptoms of GERD.

Primary hypothyroidism is usually the result of Hashimoto's thyroiditis, thyroidectomy, or radioactive iodine therapy. Treatment of hypothyroidism with replacement doses of thyroid hormone is usually lifelong. Levothyroxine is the drug of choice.

The treatment of atrial fibrillation includes anticoagulation, rate control, and rhythm control. New US guidelines for the management of atrial fibrillation have recently been published.

H2-RECEPTOR ANTAGONISTS (H2RAs) — Currently available H2RAs are listed in Table 1. These drugs inhibit the action of histamine at the H2-receptor of the gastric parietal cell, decreasing basal acid secretion and, to a lesser degree, food-stimulated acid secretion. All H2RAs are about equally effective for treatment of PUD and GERD. H2RAs are faster acting than PPIs in relieving symptoms of dyspepsia or GERD, but they are not as effective as PPIs in relieving symptoms or in healing erosive esophagitis. Repeated administration of H2RAs leads to pharmacologic tolerance and has been associated with the development of new dyspeptic symptoms. Rebound acid hypersecretion can occur after stopping H2RAs.

Peptic ulcer disease (PUD) is usually caused by nonsteroidal anti-inflammatory drugs (NSAIDs) or by infection with Helicobacter pylori. Gastroesophageal reflux disease (GERD) can be caused by transient lower esophageal sphincter relaxation, reduced lower esophageal sphincter tone, hiatal hernia, delayed gastric emptying or hormonal changes due to pregnancy. Acid suppressive therapy is the cornerstone of management for both PUD and GERD.

Primary hypothyroidism is usually the result of Hashimoto's thyroiditis, thyroidectomy for hyperthyroidism, goiter or cancer, or radioactive iodine therapy for hyperthyroidism.

Peptic ulcers caused by treatment with nonsteroidal anti-inflammatory drugs (NSAIDs) are mainly gastric ulcers. Most duodenal and other gastric ulcers are caused by the gram-negative bacillus Helicobacter pylori. Gastroesophageal reflux disease (GERD) is caused by gastric acid reflux into the esophagus. Drugs that suppress gastric acid production are the primary treatment for GERD and peptic ulcers.

A reader expressed disappointment that our recent listing of “Some Warfarin Drug Interactions”1 did not include acetaminophen. Perhaps it should have. Acetaminophen can increase the anticoagulant effect of warfarin, particularly with continued use, but it does so inconsistently. The mechanism of this interaction has not been established, but may be related to an acetaminophen metabolite inhibiting vitamin K-epoxide reductase, the target for warfarin’s anticoagulant effect.2

Patient susceptibility varies, possibly on a genetic basis; occasional use of acetaminophen generally has little or no effect on the international normalized ratio (INR) in patients on chronic warfarin therapy, but in some, even a few grams of the drug may cause a dramatic increase in INR. One study in healthy subjects found no effect of acetaminophen 4 g per day for 2 weeks, while another study in patients with the same acetaminophen dose for the same period of time found a moderate increase in INR.3,4 It might be prudent to monitor INR in patients on chronic warfarin therapy more closely than usual when they take more than 2 g per day of acetaminophen for more than a few days.

1. Pharmacogenetic-based dosing of warfarin. Med Lett Drugs Ther 2008; 50:39.
2. HH Thijssen et al. Paracetamol (acetaminophen) warfarin interaction: NAPQI, the toxic metabolite of paracetamol, is an inhibitor of enzymes in the vitamin K cycle. Thromb Haemost 2004; 92:797.
3. D Kwan et al. The effects of acetaminophen on pharmacokinetics and pharmacodynamics of warfarin. J Clin Pharmacol 1999; 39:68.
4. I Mahe et al. Paracetamol: A haemorrhagic risk factor in patients on warfarin. Br J Clin Pharmacol 2005; 59:371.

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Warfarin sodium (Coumadin, and others) and other coumarin anticoagulants prevent thrombosis, but patient response is highly variable and overanticoagulation can lead to hemorrhage. Genotyping patients for single nucleotide polymorphisms (SNPs) that affect coumarin metabolism and sensitivity may help clinicians estimate the therapeutic warfarin dose. The FDA has added a note to warfarin labeling recommending lowrange doses for patients with such genetic variations. Commercial tests for these variants are now available and cost about $500 per test.

Most peptic ulcers not caused by nonsteroidal anti-inflammatory drugs (NSAIDs) are associated with infection of the gastric mucosa by the gram-negative bacilli Helicobacter pylori. The majority of NSAID-related ulcers are gastric. H. pylori infection causes both duodenal and gastric ulcers. Eradication of H. pylori promotes healing and markedly decreases recurrence of both duodenal and gastric ulcers (A Shiotamni and DY Graham, Med Clin North Am 2002; 86:1447; FKL Chan and WK Leung, Lancet 2002; 360:933). The first step in the management of peptic ulcers is the diagnosis and treatment of H. pylori.

Trovafloxacin (Trovan - Pfizer) and its prodrug alatrofoxacin (Trovan IV) are new fluroroquinolones marketed for an unusually wide variety of infections, including oral and intravenous treatment of nosocomial and community-acquired pneumonia, acute ecerbations of chronic bronchitis, acute sinusitis, complicate intra-abdominal and pelvic infections, diabetic foot infection, uncomplicated urinary tract infection, prostatitis, cervicitis and uncomplicated gonorrhea.

Grepafloxacin (Raxar - Glaxo Wellcome), a once-daily oral fluoroquinolone, is now being marketed for treatment of community-acquired pneumonia, acute bacterial exacerbations of chronic bronchitis, uncomplicated gonorrhea, and nongonococcal urethritis and cervicitis.

Most peptic ulcers not caused by nonsteroidal anti-inflammatory drugs (NSAIDs) are now thought to be associated with infection of the gastric mucosa by the gram-negative bacilli Helicobacter pylori. The majority of NSAID-related ulcers are gastric. H. pylori have been associated with both duodenal and gastric ulcers. Eradication of H. pylori promotes healing and markedly decreases recurrence of both duodenal and gastric ulcers (AH Soll, JAMA, 275:622, 1996).

Lansoprazole (Prevacid -TAP), a proton pump inhibitor similar to omeprazole (Prilosec - Medical Letter, 32:19, 1990), has been approved by the US Food and Drug Administration for short-term treatment of active duodenal ulcer and erosive reflux esophagitis and for long-term treatment of chronic hypersecretory conditions, including the Zollinger-Ellison syndrome.

Most peptic ulcers not caused by nonsteroidal anti-inflammatory drugs (NSAIDs) are now thought to be associated with infection of the gastric mucosa by the gram-negative bacilli Helicobacter pylori (NIH Consensus Development Panel, JAMA, 272:65, July 6, 1994). NSAID-related ulcers are usually gastric. H. pylori have been associated with both duodenal and gastric ulcers.

Enoxacin (en ox' a sin; Penetrex - Rh ne-Poulenc Rorer), a fluoroquinolone antimicrobial for oral use, has now been marketed in the USA for treatment of urinary tract infections and uncomplicated urethral or cervical gonorrhea.

Temafloxacin (Omniflox - Abbott) and lomefloxacin (Maxaquin - Searle) are the latest fluoroquinolone antimicrobial agents to be approved by the US Food and Drug Administration (FDA) for oral treatment of various infections. Previously marketed include norfloxacin (Noroxin - Medical Letter, 29:25, 1987), ciprofloxacin (Cipro - Medical Letter, 30:11, 1988), and ofloxacin (Floxin - Medical Letter, 33:71, 1991). Norfloxacin is marketed only for treatment of urinary tract infections, and lomefloxacin only for treatment of urinary tract infections and bronchitis known to be caused by Haemophilus influenzae or Moraxella catarrhalis. Ciprofloxacin and ofloxacin are also available in parenteral formulations.

Drugs that accelerate healing and prevent relapse or reurrence of peptic ulcers act either by decreasing gastric acidity or by enhancing mucosal defense mechanisms. Risk factors that may cause breakdown of mucosal defenses include the use of aspirinor other nonsteroidal anti-inflammatory drugs (NSAIDs) and the presence of Helicobacter pylori bacterial in the gastric antrum (AH Soll, Engl J Med, 322:909, 1990; WL Peterson, N Engl J Med, 324:1043, 1991).

Ofloxacin (Floxin - McNeil, Ortho), a new fluoroquinolone antibacterial agent, was recently marketed in the USA for oral treatment of various infections caused by susceptible microorganisms. Ofloxacin is the third fluoroquinolone to become available in this country. Norfloxacin (Noroxin - Medical Letter, 29:25, 1987) is marketed only for treatment of urinary tract infections. Ciprofloxacin (Cipro - Medical Letter, 30:11, 1988), like ofloxacin, is approved for use in a variety of infections.