Cardiac arrythmias

Winfree A T 1987 When Time Breaks Down The Three Dimensionai Dynamics of Eiectrochemicai l/l/aves and Cardiac Arrythmias Pr r cetor, NJ Princeton University Press)... 

Common side effects of theophylline therapy include headache, dyspepsia, and nausea. More serious side effects such as lethal seizures or cardiac arrythmias can occur if blood levels are too high. Many derivatives of theophylline have been prepared in an effort to discover an analogue without these limitations (60,61). However, the most universal solution has resulted from the development of reHable sustained release formulations. This technology limits the peaks and valleys in semm blood levels that occur with frequent dosing of immediate release formulations. ControUed release addresses the problems inherent in a dmg which is rapidly metabolized but which is toxic at levels ( >20 7g/mL) that are only slightly higher than the therapeutically efficacious ones (10—20 p.g/mL). Furthermore, such once-a-day formulations taken just before bedtime have proven especially beneficial in the control of nocturnal asthma (27,50,62). 

Hadeed A., Siegel S., Newborn cardiac arrythmias associated with maternal caffeine use during pregnancy. Clin. Pediatr., 1993, 32, 1, 45-48. 

K+ channels K-atp Rat brain Diabetes, asthma, cardiac arrythmia, angina, cardiac and cerebral ischemia, thrombosis, hypertension, incontinence, pain, neurogenic inflammation, epilepsy, stroke, hair growth Control of insulin release, vasodilatation, protection against cell ischemia... 

Isobutane has been found to sensitize the myocardium to epinephrine in various animal studies. Concentrations of 50,000 ppm predisposed the dog heart to cardiac arrythmias induced by catecholamines. Monkeys administered 50,000-100,000 ppm for 5 minutes via tracheal cannulation had tachycardia, arrhythmias, and myocardial depression. Cases of sudden death due to fatal cardiac arrhythmias have been reported in humans intentionally inhaling isobutane. ... 

Calcium and magnesium homeostasis is altered by chronic diuretic therapy. Loop diuretics increase the urinary excretion of Ca2+ and can lead to stone formation. Thiazide administration, on the other hand, has the opposite effect and causes frank hypercalcaemia in some patients. Both thiazide and loop drugs increase the urinary loss of Mg2+ and this has been associated with cardiac arrythmias in the elderly. 

In addition to vomiting and diarrhea, severe toxicity can occur with erroneous or intentional overdoses. These include cardiac arrythmias and atrial tachycardia with atrial-ventricular (AV) block. These effects are due to increased intracellular calcium. Hyperkalemia also occurs. Disturbances of cognitive function, including visual disturbances, delirium, and convulsion are also adverse effects resulting from neuronal effects. 

The toxic effect is known as histotoxic hypoxia. Cyanide also directly stimulates chemoreceptors, causing hyperpnea. Lack of ATP will affect all cells, but heart muscle and brain are particularly susceptible. Therefore, cardiac arrythmias and other changes often occur, resulting in circulatory failure and delayed tissue ischemic anoxia. Death is usually due to respiratory arrest resulting from damage to the CNS, as the nerve cells of the respiratory control center are particularly sensitive to hypoxia. The susceptibility of the brain to pathological damage may reflect the lower concentration of cytochrome oxidase in white matter. 

Cav 1.3 L-type 1D cochlear neurons, endocrine cells tonic neurotransmitter release, hormone secretion DHPs cardiac arrythmias, deaf... 

CNS depression, cardiac arrythmias, respiratory depression, and death. Halo-genated hydrocarbons decompose when heated and become a toxic gas (e.g., hydrogen chloride, phosgene). Evaporation of halogenated hydrocarbons as propellants causes intense cold, which leads to numbness. These gases have been used as topical analgesics. 

Cardiac arrythmias Abnormal beating rhythms in the heart. 

Enflurane is a structural isomer of isoflurane. It is more soluble than isoflurane. It causes more respiratory depression than the other volatile anaesthetics and hypercapnia is almost inevitable in patients breathing spontaneously. It causes more cardiovascular depression than isoflurane and is occasionally associated with cardiac arrythmias. Two percent of enflurane is metabolised and prolonged administration or use in enzyme-induced patients generates sufficient free inorganic fluoride from the drug molecule to cause polyuric renal failure. There have been a few cases of jaimdice and heptatoxicity associated with enflurane but the incidence of about one in 1-2 million anaesthetics is lower than with halothane. 

Cinchona species (Rubiaceae) are sources of quinine and quinidine, containing a quinoline nucleus and derived through the extensive elaboration of strictosidine (Fig. 42). The intriguing history of the antimalarial quinine and its role in world politics over the past 350 years are legendary. It is frequently the only antimalarial drug to which patients are not resistant. Its widest use, however, is in the beverage industry in tonic water. Quinidine, an isomer of quinine, is used to treat cardiac arrythmias. 

Because the molecules are delivered rapidly into the bloodstream, there is a much more rapid onset of action than with any other non-i.v. delivery method. This can be particularly useful in indications where speed is important such as pain control, relief of muscle spasm, panic/anxiety attacks, hypertensive crises, cardiac arrythmias, anaphylaxis (severe allergies to food and insect bites), nausea, cardiovascular conditions (arrhythmia, strokes), Parkinson s lock-up, and epileptic seizures. 

The oral, intraperitoneal, and intravenous LD50 values of potassium chloride in rats are 2600, 660, and 142 mg kg respectively. Signs of acute toxicity may include convulsions and seizures, cardiac arrythmias, dyspnea, cyanosis, nausea, and vomiting. 

Ebert SN, Liu XK, Woolsley RL. 1998. Female gender as a risk factor for drug-induced cardiac arrythmias evaluation of clinical and experimental evidence. J. Womens Health 7 547-557. 

YEW Taxus baccata, L., Family Taxaceae, is mainly cultivated as a decorative shrub in gardens. The whole plant, with the exception of the red fruit , is poisonous due to the alkaloid taxine. Children who have eaten the red berries and chew the taxine-containing seeds and needles can be poisoned. However, if the seeds are swallowed intact, the taxine will not be absorbed. Vomiting, stomach pains and diarrhoea are initial symptoms, which appear within half to one hour further symptoms include cardiac arrythmia, weakness of the muscles and possibly circulatory collapse. 

ACUTE HEALTH RISKS irritation to nose and throat drowsiness unconsciousness anesthetic effects liquid can cause frostbite may lead to dizziness, lack of coordination cardiac arrythmias may be noted at high exposure levels. 

Reseai ch aimed at the identification of novel antiarrythmic agents is targeting Cl channels. Cl channels are involved in cardiac arrythmia, asthma, CF and diarrhea, thus representing targets for therapeutic approaches. 

Adverse reactions Thiamine rare anaphylaxis after a large IV dose Riboflavin none known Niacin or nicotinic acid Cardiac arrythmias may occur rarely Pyridoxine Lxmg-term megadoses may produce sensory neuropathy... 

Morganroth, J., Bigger, J. T., and Anderson, J. L., Treatment of ventricular arrhythmias by United States cardiologists a survey before the Cardiac Arrythmia Suppression Trial results were available. Am. J. Cardiol., 65 40-48, 1990. 

IV phenytoin may be useful in the treatment of paroxysmal atrial tachycardia, ventricular tachycardia and digitalis-induced cardiac arrythmias. 

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