Quinidine gastrointestinal effects

When large amounts are taken, e.g. (unreliably) to induce abortion or in attempted suicide, ocular disturbances, notably constriction of the visual fields, may occur and even complete blindness, the onset of which may be very sudden. Vomiting, abdominal pain and diarrhoea result from local irritation of the gastrointestinal tract. Quinidine-like effects include hypotension, disturbance of atrioventricular conduction and cardiac arrest. Activated charcoal should be given. Supportive measures are employed thereafter as no specific therapy has proven benefit. 

The adverse effects of quinidine can be divided into cardiac and non-cardiac manifestations. Depression and paraphimosis are seen in many horses treated with quinidine sulfate and resolve once treatment is discontinued. Gastrointestinal effects include flatulence, which is rarely of clinical significance, and colic and diarrhea, both of... 

Clinical signs of toxicity most frequently include sedation, coma, hypotension, extrapyramidal effects, and cardiac arrhythmias. Anticholinergic effects including blurred vision, decreased gastrointestinal motility, delirium, hallucinations, hyperthermia, and tachycardia have been seen. Cardiac effects include mild hypotension, prolonged Q-T interval, and ventricular dysrhythmias. Quinidine-like effects have rarely resulted in sudden cardiac death. The most commonly reported extrapyramidal symptoms include dystonia, akathisia, and parkinsonism. Respiratory depression, loss of gag... 

The most common adverse effects associated with quinidine administration are diarrhea (35%), upper gastrointestinal distress (25%), and light-headedness... 

Adverse effects With chronic use, procainamide causes a high incidence of side effects, including a reversible lupus erythe-matosus-like syndrome that develops in 25 to 30% of patients. Toxic concentrations of procainamide may cause asystole or induction of ventricular arrhythmias. Central nervious system (CNS) side effects include depression, hallucination and psychosis. With this drug, gastrointestinal intolerance is less frequent than with quinidine. 

The commonest adverse effects of mexiletine are on the nervous system, and include centrally mediated gastrointestinal distress (38%), light-headedness (20%), tremor (12%), and coordination difficulties (11%). The figures in parentheses are quoted from a study in which mexiletine was compared with quinidine (26). Other reported adverse effects include changes in sleep habit, weakness, headache, visual problems, and nervousness. Slurred speech, dysarthria, diplopia, and ataxia have also been reported (18). 

The beneficial effects were related to these plasma concentrations, as were the time to the first bout of atrial fibrillation, the frequency of bouts of atrial fibrillation, and the time between episodes. However, when atrial fibrillation occurred there was no difference in the ventricular rate in the different groups. Adverse effects necessitated drug withdrawal in four patients one had heart failure and two had gastrointestinal symptoms. These effects were not dose-related, although there were too few occurrences for a definitive conclusion. The authors suggested that this stepwise approach, with increasing doses of propafenone and increasing doses of quinidine could be beneficial in the treatment of paroxysmal atrial fibrillation. 

Gastrointestinal symptoms, including anorexia, nausea, and vomiting, are common. Quinidine has a negative inotropic effect on the heart and can cause heart failure and hypotension. It prolongs the QRS complex and QT interval and can cause cardiac dysrhythmias, which can... 

Quinidine has a wide spectmm of adverse effects but causes increased—not decreased—gastrointestinal motility and often results in diarrhea. Procainamide causes lupus quinidine causes thrombocytopenia amiodarone causes thyroid dysfunction. The answer is (A). 

D. Enhancement of Elimination Enhancement of elimination is possible for a number of toxins, including manipulation of urine pH to accelerate renal excretion of weak acids and bases. For example, alkaline diuresis is effective in toxicity due to fluoride, isoniazid, fluoroquinolones, phenobarbital, and salicylates. Urinary acidiflcation may be useful in toxicity due to weak bases, including amphetamines, nicotine, and phencyclidine, but care must be taken to avoid acidosis and renal failure in rhabdomyolysis. Hemodialysis or hemoperfusion enhances the elimination of many toxic compounds, including acetaminophen, ethylene glycol, formaldehyde, lithium, methanol, procainamide, quinidine, salicylates, and theophylline. Cathartics such as sorbitol (70%) may decrease absorption and hasten removal of toxins from the gastrointestinal tract. 

In addition, a common contaminant in quinidine preparations, dihydroquinidine, which is derived from reduction of the quinuclidine vinyl group at C-3 to an ethyl group, also may contribute to its activity (32). Although similar to quinidine in pharmacodynamic and pharmacokinetic behavior, this contaminant is both more potent as an antiarrhythmic and more toxic. Thus, levels of this contaminant may contribute to variability between commercial preparations. The most frequent adverse effects associated with quinidine therapy are gastrointestinal ... 

Oral quinidine is nsed to treat snpraventricular and ventricular arrhythmias. A loading dose is usually not reqnired as is reached in approximately 24 h (ty2 6 h). An oral loading may be associated with severe gastrointestinal side effects. Intravenons quinidine is nsnally avoided becanse of hypotension. ... 

C. Other effects. Quinidine commonly causes nausea, vomiting, and diarrhea after acute ingestion and, especially with chronic doses, cinchonism (tinnitus, vertigo, deafness, or visual disturbances). Procainamide may cause gastrointestinal upset and, with chronic therapy, a lupus-like syndrome. 

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