Details About Overdose or Poisoning Generic Salt :: Vasopressin
Vasopressin
Drug Pharmacology ::
I. Pharmacology./b>
A. Vasopressinis a peptide hormone that is synthesized in the hypothalamus. Theprimary stimuli for endogenous physiologic release are hyperosmolality,hypotension, and hypovolemia. It is used in the critical care settingfor severe catecholamine-resistant vasodilatory shock, in which case itacts as a potent vasoconstrictor. Conditions in which vasopressin hasshown to be beneficial include septic shock, postcardiotomy shock,milrinone-induced hypotension, and the late phase of hemorrhagic shock.There is insufficient and conflicting human and animal data torecommend its use routinely to manage shock from poisoning. Furtherdata are needed to define its risks, benefits, and optimum dose.Increases in arterial pressure should be evident within the first hour.Its serum half-life is less than 15 minutes.
Drug Indications ::
Indications
A. Note: Vasopressinshould not be used as a first-line agent to treat hypotension. It isused as add-on therapy to treat severe vasodilatory hypotension that isunresponsive or refractory to one or more adrenergic agents (eg,high-dose dopamine, epinephrine, norepinephrine, phenylephrine). Thereare only four case reports in the medical literature in whichvasopressin was used for overdose. The drug poisonings treated in thosepatients were amlodipine, caffeine, milrinone, and amitriptyline.Animal models of verapamil toxicity have not demonstrated anyhemodynamic or survival benefit.
B. As a means to reduce adrenergic agent requirements while treating vasodilatory hypotension.
Drug Contra-Indications ::
III. Contraindications./b>
A. Vasopressin infusion should be discontinued if there is a decrease in the cardiac index and/or stroke volume. Note:Serious consideration should be given to monitoring cardiac indexesinvasively via a pulmonary artery catheter to titrate hemodynamiceffects and dosing.
B. Usewith extreme caution if there is evidence of decreased cardiac outputdespite adequate intravascular volume or evidence of cardiogenic shock.
C. Vasopressinshould be used cautiously in treating an overdose of an agent that hasmyocardial depressant effects (eg, calcium channel blockers, betablockers).
Drug Adverse Effects ::
IV. Adverse effects
A. Negative inotropic effect.
1. Vasopressinhas been shown to result in a decrease in the cardiac index. This maybe attributed to an increase in systemic vascular resistance andafterload on a depressed myocardium or may be related in part to acompensatory decrease in heart rate. Dobutamine and milrinone have beenused in conjunction with vasopressin in attempts to attenuate thisnegative inotropic effect.
B. Ischemia (especially at doses > 0.05 U/minute)
1. Cardiac arrest has been reported at doses > 0.05 U/min.
2. Ischemic skin lesions of the distal extremities and trunk and lingual regions.
3. Mesenteric ischemia and hepatitis may occur.
C. Thrombocytopenia
D. Use in pregnancy.FDA category B (see Table III–1). There are no reports linking the useof vasopressin with congenital defects. Vasopressin and the relatedsynthetic agents desmopressin and lypressin have been used duringpregnancy to treat diabetes insipidus.
Drug Dose Management ::
Dosage and method of administration
A. Intravenousinfusion at 0.01–0.04 U/min. Vasopressin should be diluted with normalsaline or 5% dextrose in water to a final concentration of 0.1–1 U/mL.Doses higher than 0.04 U/min are not recommended and may be associatedwith a greater incidence of adverse effects (see above). Administrationthrough central venous access is recommended to minimize the risk ofextravasation. Local skin necrosis has occurred when vasopressin wasinfused through a peripheral venous catheter.
B. Oncean adequate blood pressure is achieved and stabilized, steps should betaken to reduce the doses of adrenergic agents and vasopressingradually.
Drug Chemical Formulations ::
Formulations
A. Vasopressin (Pitressin™ and others): 20 U/mL, 0.5-, 1-, and 10-mL vials.
B. The suggested minimum stocking level to treat a 70-kg adult for the first 24 hours is 60 U (six vials of 0.5 mL, three vials of 1 mL, or one vial of 10 mL).
