Difference between revisions of "Interventional Agents"
| (15 intermediate revisions by 2 users not shown) | |||
| Line 1: | Line 1: | ||
| − | + | {{toplink | |
| + | |linkpage =Anaesthesia | ||
| + | |linktext =Anaesthesia | ||
| + | |maplink= Anaesthesia Content Map - WikiClinical | ||
| + | |sublink1=Anaesthetic Drugs | ||
| + | |subtext1=Anaesthetic Drugs | ||
| + | |pagetype=Clinical | ||
| + | }} | ||
Anaesthetic agents have a number of side effects and it is often necessary to treat these issues using some of the following drugs - | Anaesthetic agents have a number of side effects and it is often necessary to treat these issues using some of the following drugs - | ||
==Dobutamine== | ==Dobutamine== | ||
| − | + | '''Dobutamine''' is a synthetic catecholamine which acts as a β1 selective adrenoceptor agonist. Dobutamine is a ''sympathomimetic'' and postive inotrope. It exerts this effect by stimulating β1 adrenergic receptors. This causes a rise in cAMP though the activation of adenylate cyclase. This increase causes an increase in slow inward calcium currents. It also increases calcium storage in the sarcoplasmic reticulum making more calcium available to contractile muscle fibres, thereby increasing myocardial contractility. It also acts at β1 and β2 receptors in the peripheral vasculature. | |
| − | |||
| − | |||
Dobutamine has a low half life and so is given via a continuous rate intravenous infusion. Due to its potential side effects however, it can only be administered for a maximum of 48 hours. | Dobutamine has a low half life and so is given via a continuous rate intravenous infusion. Due to its potential side effects however, it can only be administered for a maximum of 48 hours. | ||
| − | ===Side Effects=== | + | ===Contraindications and Side Effects=== |
| − | * | + | *Hypertension |
*Cardiac arrhythmias | *Cardiac arrhythmias | ||
| + | |||
| + | ===Indications=== | ||
| + | Used in patients with heart failure. It can be used as emergency treatment in patients with cardiogenic shock. It can be used in anaesthesia when there is hypotension or bradycardia due to poor myocardial contractility. | ||
==Dopamine== | ==Dopamine== | ||
| − | + | Dopamine is a noradrenaline precursor which acts on both α and β cardiac receptors, as well as dopaminergic receptors found peripherally. It is a positive inotrope. It is very similar to dobutamine in action. It should be administered via a continuous rate infusion. It is used short term for patients with systolic dysfunction as well as management of oliguric renal failure. It can be used as a pressor agent to help treat inappropriate hypotension in concious and anaesthetised patients. | |
| − | |||
| − | Dopamine is a noradrenaline precursor which acts on both α and β cardiac receptors, as well as dopaminergic receptors found peripherally. It is a positive inotrope | ||
| − | |||
==Ephedrine== | ==Ephedrine== | ||
| − | + | '''Ephedrine''' has the same action as epinephrine but has slightly different properties. It is similar to amphetamines in that ephedrine causes noradrenaline release leading to catecholaminergic receptor stimulation. Ephedrine has a lower potency but longer duration of action when compared with epinephrine. It also has more pronounced CNS effects. | |
| − | |||
| − | |||
| − | |||
| − | ===Contraindications=== | + | ===Contraindications and Side Effects=== |
| − | |||
| − | |||
*Irritability | *Irritability | ||
*Tachycardia | *Tachycardia | ||
*Hypertension | *Hypertension | ||
*Anorexia | *Anorexia | ||
| + | *Avoid in patients with severe cardiovascular disease | ||
| + | *Caution in patients diabetes mellitus, hyperthyroidism, prostatic hypertrophy and glaucoma. | ||
| − | + | ===Indications=== | |
| + | Ephedrine can be used to increase the tone of the bladder spincter in cases of urinary incontinance; it can also be used as a bronchoconstrictor as well as a pressor agent for shock patients. | ||
| − | + | ==Phenylephrine== | |
| + | Phenylephrine is an α adrenergic sympathomimetic used to treat hypotension without cardiac stimulation. Due to metabolism in the gastrointestinal tract, it is available in an injectable form. It acts by causing peripheral vasoconstriction leading to an increase in blood pressure, both systolic and diastolic. However, a reflex bradycardia may be seen. There is a increase in coronary blood flow. | ||
| − | |||
| − | |||
| − | + | It is used to treat hypotension caused by a number of factors including barbituate anaesthesia, and has diagnostic opthlamic uses also. If administered intravenously onset is almost immediate, and duration of action is approximately 20 minutes, while if administered intramuscularly onset of action is approximately 10-15 minutes with a duration of action approximately 1 hour. | |
| + | |||
===Contraindications=== | ===Contraindications=== | ||
| Line 47: | Line 50: | ||
==Vasopressin== | ==Vasopressin== | ||
| − | + | Vasopressin is a non-catecholamine vasopressor. It is a hypothalamic hormone found in the posterior pituitary. It promotes the renal reabsorption fo water as well as smooth muscle contraction particularly of capillaries and small arterioles. This smooth muscle contraction may lead to decreased blood flow to systems but increased hepatic blood flow. Vasporessin is indicated in patients with vasodilatory shock or ventricular fibrillation. However, possible side effects include vasconstriction and arrhythmias. It should be avoided in patients with vascular disease, history of seizures, heart failure, asthma or pregnant patients. | |
| − | |||
| − | Vasopressin is a non-catecholamine vasopressor. It is a | ||
| − | |||
| − | |||
| − | |||
| − | |||
| − | |||
| − | |||
| − | |||
| − | |||
| − | |||
| − | |||
| − | |||
Revision as of 18:10, 8 September 2010
|
Anaesthetic agents have a number of side effects and it is often necessary to treat these issues using some of the following drugs -
Dobutamine
Dobutamine is a synthetic catecholamine which acts as a β1 selective adrenoceptor agonist. Dobutamine is a sympathomimetic and postive inotrope. It exerts this effect by stimulating β1 adrenergic receptors. This causes a rise in cAMP though the activation of adenylate cyclase. This increase causes an increase in slow inward calcium currents. It also increases calcium storage in the sarcoplasmic reticulum making more calcium available to contractile muscle fibres, thereby increasing myocardial contractility. It also acts at β1 and β2 receptors in the peripheral vasculature.
Dobutamine has a low half life and so is given via a continuous rate intravenous infusion. Due to its potential side effects however, it can only be administered for a maximum of 48 hours.
Contraindications and Side Effects
- Hypertension
- Cardiac arrhythmias
Indications
Used in patients with heart failure. It can be used as emergency treatment in patients with cardiogenic shock. It can be used in anaesthesia when there is hypotension or bradycardia due to poor myocardial contractility.
Dopamine
Dopamine is a noradrenaline precursor which acts on both α and β cardiac receptors, as well as dopaminergic receptors found peripherally. It is a positive inotrope. It is very similar to dobutamine in action. It should be administered via a continuous rate infusion. It is used short term for patients with systolic dysfunction as well as management of oliguric renal failure. It can be used as a pressor agent to help treat inappropriate hypotension in concious and anaesthetised patients.
Ephedrine
Ephedrine has the same action as epinephrine but has slightly different properties. It is similar to amphetamines in that ephedrine causes noradrenaline release leading to catecholaminergic receptor stimulation. Ephedrine has a lower potency but longer duration of action when compared with epinephrine. It also has more pronounced CNS effects.
Contraindications and Side Effects
- Irritability
- Tachycardia
- Hypertension
- Anorexia
- Avoid in patients with severe cardiovascular disease
- Caution in patients diabetes mellitus, hyperthyroidism, prostatic hypertrophy and glaucoma.
Indications
Ephedrine can be used to increase the tone of the bladder spincter in cases of urinary incontinance; it can also be used as a bronchoconstrictor as well as a pressor agent for shock patients.
Phenylephrine
Phenylephrine is an α adrenergic sympathomimetic used to treat hypotension without cardiac stimulation. Due to metabolism in the gastrointestinal tract, it is available in an injectable form. It acts by causing peripheral vasoconstriction leading to an increase in blood pressure, both systolic and diastolic. However, a reflex bradycardia may be seen. There is a increase in coronary blood flow.
It is used to treat hypotension caused by a number of factors including barbituate anaesthesia, and has diagnostic opthlamic uses also. If administered intravenously onset is almost immediate, and duration of action is approximately 20 minutes, while if administered intramuscularly onset of action is approximately 10-15 minutes with a duration of action approximately 1 hour.
Contraindications
- Hypertension
- Ventricular Tachycardia
- Geratric patients
- Pregnant patients - causes uterine contraction.
Vasopressin
Vasopressin is a non-catecholamine vasopressor. It is a hypothalamic hormone found in the posterior pituitary. It promotes the renal reabsorption fo water as well as smooth muscle contraction particularly of capillaries and small arterioles. This smooth muscle contraction may lead to decreased blood flow to systems but increased hepatic blood flow. Vasporessin is indicated in patients with vasodilatory shock or ventricular fibrillation. However, possible side effects include vasconstriction and arrhythmias. It should be avoided in patients with vascular disease, history of seizures, heart failure, asthma or pregnant patients.