The increased demand for the knowledge of fluid and electrolytes balances follows the advances in the medical field and the invention of new treatment modalities. Fluid balance is essential for the normal functioning of the body, and it requires that medical professionals deal with any cause of imbalance in a timely manner. Water is the basic fluid component of the body, which forms about 60% of the total body weight of an average adult body and approximately 80% of the total body weight of a newborn infant (Methemy 4). In cases of imbalances, there are drugs given to patients to ensure maintenance of balance and these drugs are in two categories, diuretics and antidiuretics, and this emanates from the fact that renal regulation of water and sodium stands as the most important mechanism of volume regulation (Roberts 378). Drugs that follow under the diuretics category include:
Generic name Brand name
Diuretic drugs
Bumetanide Bumex
Furosemide Lasix
Clorothiazide Diuril
Chlorthalidone Hygroton
Metalozone Zarolyn
Triamterene Dyrnium
Acetazolamide Diamax
Antidiuretic drugs
Vasopressin Pitressin
Desmopressin DDAVP(Stimate)
Electrolyte imbalances arise from abnormal water levels, and the most treated electrolyte imbalances are those related to sodium, potassium, and calcium. The numbers of positive ions have to be equal to negatively charged ions for proper functioning of the body (McLoughlin 1). The treatment of electrolyte imbalance depends on the excess or limit of certain electrolytes whose medication functions to correct the abnormality.
Diuretic drugs
Are agents, which act directly on the kidney to increase the rate and extent of urine production.
Indications
Diuretics are responsible for the treatment of oedema that is associative of congestive heart failure or with liver or renal failure. They can also function as adjuncts for treatment of hypertension (McLoughlin 1).
Mechanism of action
They act through inhibition of tubular reabsorption, and this means that they increase the elimination of water and electrolytes (Roberts 378). In the kidney, thousands of nephrons act as filters. The drugs act at different points along the Nephron tubules of the kidney as they influence the carrier systems that transfer ions into and out of the nephrons.
Contraindications
Administration of diuretics is contraindicated in patients with electrolyte imbalance or known drug hypersensitivity. Use of diuretics in patients with renal dysfunction should be cautionary because changes in blood flow and kidney perfusion my compromise the kidney disease further (McLoughlin 1). There should also be caution when used in patients with diabetes mellitus because the diuretics have glucose elevating effects. Some of the side effects of diuretics is that they compete with uric acid secretion in the proximal tubule leading to a buildup of uric acid, which may lead to hyperuricaemia and gout. In the elderly, there is a recommendation of lower doses because the elderly are more susceptible to the side effects. Finally, thiazides and loop diuretics are not recommendable during pregnancy unless the benefits of the mother outweigh that of the fetus. This is because the diuretics cross the placenta with others causing fetal abnormalities (McLoughlin 1).
Side effects
Hypokalaemia, hypochloraemia, metabolic acidosis, hypnotraemia and gastrointestinal reactions are some of the side effects of diuretics. Some others include headache, fatigue, hyperglycaemia and blurred vision.
Drug interactions
Interactions of diuretics may occur with nonsteroidal anti inflammatory agents, corticosteroids, lithium, hypotensive agents, anticonvulsants, and antidiabetic agents (McLoughlin1).
Antidiuretic drugs
Antidiuretics suppress urine formation and rate of excretion where they increase reabsorption of water and electrolytes from the distal tubule and collecting ducts.
Indications
The primary indication for antidiuretics is in the treatment of diabetes inspidus and shock as a vasoconstrictor. It can also be useful in the treatment of postoperative abdominal distention (Methemy, 209).
Mechanism of action
Antidiuretics function to increase water reabsorption, vasoconstriction and promotion of release of coagulation factor 8 (Roberts 379). This is achievable through activation of three different receptors, where the activation of the receptors causes an increase in intracellular calcium levels and contraction of smooth muscle cells of red blood cells leading to vasoconstriction. These mechanisms enable maintenance of normal blood volume and osmorality in the regulation of blood pressure.
Contraindications
There is a contraindication of antidiuretic drugs in patients with hypersensitivity to the aforementioned drugs or their components.
Side effects
Local or systemic allergic reactions may occur in hypersensitive individuals, vomiting, and passage of gas tremor, bronchial constriction, and sweating.
Drug interactions
Carbamazepine, chlorpropamide and tricyclic, antidepressants may potentiate the antidiuretic effect of antidiuretic drugs whereas heparin, norepinephrine may decrease the antidiuretic effect when used concurrently with antidiuretic drugs (Methemy 226).
Fluid and electrolyte solutions commonly used in the management of fluid and electrolyte disorders are many. Some of them are dextrose in water, hypotonic and isotonic saline conditions and dextrose in saline (Roberts 377). Others include polyionic Ringer’s lactate, dextrose in polyionic solutions, potassium chloride, sodium chloride, magnesium sulfate and phosphorous electrolyte solutions. The use of solutions in the management and electrolyte disorders depend on what cation or anion that is causing the disorder. When administering Calcium chloride or calcium gluconate solutions, it is advisable that the administrate rate be slower than when administering other electrolyte solutions. This is to avoid necrosis and sloughing at the site of administration into the skin (Roberts 377). This is not the same with the administration of sodium chloride electrolyte solution that be administered in its concentrated form. However5, it is advisable that the administration of potassium chloride should not be through an intravenous push or undiluted potassium. The same applies to magnesium sulfate electrolyte solution that is not recommendable for administration through an IV push.
References
McLoughlin, C. (2004). Diuretic drugs. Nursing times learning. Retrieved 11 November
2012,from
<http://www.nursingtimes.net/diuretic-drugs/199431.article>
Methemy, N. (2011). Fluid and electrolyte balance. Burlington, Massachusetts, Jones & Bartlett
Publishers.
Roberts, K.E. (2000). Fluid and electrolyte regulation. Pp 369-379. Retrieved 11 November
2012, from
<http://repository.upenn.edu/cgi/viewcontent.cgi?filename=10&article=1003&context=miscellaneous_papers&type=additional>
