Gastrointestinal function vomiting

Gastrointestinal Nausea, vomiting, abdominal cramps, abnormal liver function tests... 

Disturbances of gastrointestinal function are often accompanied by electrolyte imbalance due to fluid losses by emesis (vomiting), volvulus (dilation), diarrhea, or other perturbations of many varied mechanisms for electrolyte and fluid homeostasis (see... 

Among disorders affecting gastrointestinal function are anorexia nervosa and bulimia nervosa, thought to occur in persons lacking self-esteem. Neurotransmitter deficits have been found in patients with bulimia, as a result of vomiting. 

Dopamine is an intermediate product in the biosynthesis of noradrenaline. Furthermore it is an active transmitter by itself in basal ganglia (caudate nucleus), the nucleus accumbens, the olfactory tubercle, the central nucleus of the amygdala, the median eminence and some areas in the frontal cortex. It is functionally important, for example in the extra-pyramidal system and the central regulation of emesis. In the periphery specific dopamine receptors (Di-receptors) can be found in the upper gastrointestinal tract, in which a reduction of motility is mediated, and on vascular smooth muscle cells of splanchnic and renal arteries. Beside its effect on specific D-receptors, dopamine activates, at higher concentrations, a- and -adrenoceptors as well. Since its clinical profile is different from adrenaline and noradrenaline there are particular indications for dopamine, like situations of circulatory shock with a reduced kidney perfusion. Dopamine can dose-dependently induce nausea, vomiting, tachyarrhythmia and peripheral vasoconstriction. Dopamine can worsen cardiac ischaemia. 

Brain serotonergic neurons are involved in numerous diffuse functions such as mood, sleep, appetite, and temperature regulation, as well as the perception of pain, the regulation of blood pressure, and vomiting (see Chapter 21). Serotonin also appears to be involved in clinical conditions such as depression, anxiety, and migraine. Serotonergic neurons are also found in the enteric nervous system of the gastrointestinal tract and around blood vessels. In rodents (but not in humans), serotonin is found in mast cells. 

HT3 receptors in the gastrointestinal tract and in the vomiting center of the medulla participate in the vomiting reflex (see Chapter 62). They are particularly important in vomiting caused by chemical triggers such as cancer chemotherapy drugs. 5-HTip and 5-HT4 receptors also play important roles in enteric nervous system function. 

Theophylline should be used only where methods to measure theophylline blood levels are available because it has a narrow therapeutic window, and its therapeutic and toxic effects are related to its blood level. Improvement in pulmonary function is correlated with plasma concentrations in the range of 5-20 mg/L. Anorexia, nausea, vomiting, abdominal discomfort, headache, and anxiety occur at concentrations of 15 mg/L in some patients and become common at concentrations greater than 20 mg/L. Higher levels (more than 40 mg/L) may cause seizures or arrhythmias these may not be preceded by gastrointestinal or neurologic warning symptoms. 

Gastrointestinal complaints (eg, nausea, diarrhea, vomiting, flatulence) are the most common adverse effects but rarely require discontinuation of therapy. Other potential adverse effects include headache and asthenia. Tenofbvir-associated proximal renal tubulopathy causes excessive renal phosphate and calcium losses and 1-hydroxylation defects of vitamin D, and preclinical studies in several animal species have demonstrated bone toxicity (eg, osteomalacia). Monitoring of bone mineral density should be considered with long-term use in those with risk factors for or with known osteoporosis, as well as in children. Reduction of renal function over time, as well as cases of acute renal failure and Fanconi s syndrome, have been reported in patients receiving tenofovir alone or in combination with emtricitabine. For this reason, tenofovir should be used with caution in patients at risk for renal dysfunction. Tenofovir may compete with other drugs that are actively secreted by the kidneys, such as cidofovir, acyclovir, and ganciclovir. 

Common adverse effects include gastrointestinal distress (nausea, vomiting, stomach cramps) and various hypersensitivity reactions (rashes and fever). Disturbances in liver function have also been noted, and serious hepatic abnormalities may occur in patients with preexisting liver disease. 

Adverse Effects. The primary problem associated with foscarnet is impaired renal function, including acute tubular necrosis. Hematologic disorders (anemia, granulocytopenia, leukopenia), gastrointestinal disturbances (cramps, nausea, vomiting), and CNS toxicity (confusion, dizziness) may also occur during foscarnet treatment. 

Adverse Effects. Hepatotoxicity is the most serious adverse effect of fluconazole this drug should be used cautiously in patients with impaired liver function. Other common side effects include headache and gastrointestinal disturbances (abdominal pain, nausea, vomiting). 

Adverse Effects. Flucytosine may cause hepatotoxicity and may also impair bone marrow function, resulting in anemia, leukopenia, and several other blood dyscrasias.69 This drug may also produce severe gastrointestinal disturbances, including nausea, vomiting, diarrhea, and loss of appetite. 

Adverse Effects. The primary side effects of azathioprine are related to suppression of bone marrow function, including leukopenia, megaloblastic anemia, and similar blood dyscrasias. Other side effects include skin rash and gastrointestinal distress (appetite loss, nausea, vomiting) hepatic dysfunction can also occur when higher doses are used. 

Three common side-effects are (a) first-dose hypotension, (b) persistent dry cough and (c) hyperkalaemia. Other side-effects include gastrointestinal effects (nausea, vomiting, dyspepsia, diarrhoea, altered liver function tests, blood disorders, angioedema, rash, loss of sense of smell (more likely if also on potassium-sparing agents or potassium supplements). 

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