Vasopressors and inotropes

Onset of action: 1-10 minutes. Peak effect: 10-20 minutes. Half-life: 2 minutes. Excretion: Urine (as metabolites).

Adult (usual): 2.5 to 20 mcg/kg/minute. Maximum: 40 mcg/kg/min. Titrate to desired response. Administer into large vein. Usual doses to increase cardiac output are 2.5 to 15 mcg/kg/minute IV.

Drip rate (500mg/250 ml) ml/hr = wt(kg) x (mcg/min) x 0.03.
Supplied: 12.5 mg/ml (20 ml, 40 ml, 100 ml)

Dosing (Adult):
Refractory CHF: initial dose: 0.5 to 2 mcg/kg/min.
Renal: 1 to 5 mcg/kg/min.
Severely ill patient: initially 5 mcg/kg/min, increase by 5 to 10 mcg/kg/min (q10 to 30 min) up to max of 50 mcg/kg/min.
Cardiac life support (initial): 2 to 5 mcg/kg/min - titrated to effect. Infusion may be increased by 1-4 mcg/kg/minute at 10 to 30 minute intervals until optimal response is obtained. If dosages >20-30 mcg/kg/minute are needed, a more direct-acting pressor may be more beneficial (ie, epinephrine, norepinephrine). [0.5 to 2 mcg/kg/min-dopa; 2-10-dopa/beta; >10-primarily alpha.]

Used to support BP, CO and renal perfusion in shock. IMPORTANT NOTE: Renal shutdown may occur at doses greater than 50 micrograms/kilogram/minute. The infusion rate should be reduced if urine flow decreases without adequate peripheral effects. Administer into large vein to prevent the possibility of extravasation (central line administration).

Calculation of drip rate (ml/hr) 400mg/250 ml: wt(kg) x mcg/min x 0.0375.

The predominant effects of dopamine are dose-related

Administration: Central line administration only.

Endotracheal: Doses (2-2.5 x IV dose) should be diluted to 10 ml with NS or distilled water prior to administration.

Anaphylaxis (adult): 0.3 mg IM (0.3 ml of a 1:1000 solution). May be repeated if severe anaphylaxis persists - repeat q10 to 15 minutes prn or give 0.1 to 0.25 mg IV (1:10,000) over 5-10min repeat q5 to 15 minutes as needed or start continuous infusion: 1 to 4 mcg/min.

Asthma: inhalational form: start with 1 inhalation, then wait at least 1 min. If not relieved, use once more. Do not use again for at least 3 hr. Asthma: subcutaneous (SC) form: 0.2-0.5 mg (0.2-0.5 ml of a 1:1000 solution) SC every 2 hr as required. In severe attacks, may repeat dose every 20 min for a maximum of 3 doses.

Cardiac arrest: 1 mg IV initially; may be repeated as necessary q 3-5 min.

FDA labeled indications: CHF, acute (short-term treatment). Non-FDA labeled indications: Cardiac surgery/low cardiac output states. Inotropic support (Advance cardiac life support).
Dosing (Adult): CHF (short term): initial: 0.75 mg/kg IV bolus over 2-3 min, may repeat in 30 minutes. Maint: 5-10 mcg/kg/min IV infusion. Recommended total daily dose, not to exceed 10 mg/kg.

Renal Dosing
Renal failure: Crcl<10 ml/min: Administer 50% to 75% of dose.

Administration of ProAmatine® results in a rise in standing, sitting, and supine systolic and diastolic blood pressure in patients with orthostatic hypotension of various etiologies. Standing systolic blood pressure is elevated by approximately 15 to 30 mmHg at 1 hour after a 10-mg dose of midodrine, with some effect persisting for 2 to 3 hours. ProAmatine® has no clinically significant effect on standing or supine pulse rates in patients with autonomic failure.

INDICATIONS AND USAGE
ProAmatine® is indicated for the treatment of symptomatic orthostatic hypotension (OH). Because ProAmatine® can cause marked elevation of supine blood pressure (BP>200 mmHg systolic), it should be used in patients whose lives are considerably impaired despite standard clinical care, including non-pharmacologic treatment (such as support stockings), fluid expansion, and lifestyle alterations. The indication is based on ProAmatine®'s effect on increases in 1-minute standing systolic blood pressure, a surrogate marker considered likely to correspond to a clinical benefit. At present, however, clinical benefits of ProAmatine®, principally improved ability to perform life activities, have not been established. Further clinical trials are underway to verify and describe the clinical benefits of ProAmatine®.

After initiation of treatment, ProAmatine® should be continued only for patients who report significant symptomatic improvement.

CONTRAINDICATIONS
ProAmatine® is contraindicated in patients with severe organic heart disease, acute renal disease, urinary retention, pheochromocytoma or thyrotoxicosis. ProAmatine® should not be used in patients with persistent and excessive supine hypertension.

WARNINGS
Supine Hypertension: The most potentially serious adverse reaction associated with ProAmatine® therapy is marked elevation of supine arterial blood pressure (supine hypertension). Systolic pressure of about 200 mmHg were seen overall in about 13.4% of patients given 10 mg of ProAmatine®. Systolic elevations of this degree were most likely to be observed in patients with relatively elevated pre-treatment systolic blood pressures (mean 170 mmHg). There is no experience in patients with initial supine systolic pressure above 180 mmHg, as those patients were excluded from the clinical trials. Use of ProAmatine® in such patients is not recommended. Sitting blood pressures were also elevated by ProAmatine® therapy. It is essential to monitor supine and sitting blood pressures in patients maintained on ProAmatine®.

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DOSAGE AND ADMINISTRATION
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The recommended dose of ProAmatine® is 10 mg, 3 times daily. Dosing should take place during the daytime hours when the patient needs to be upright, pursuing the activities of daily living. A suggested dosing schedule of approximately 4-hour intervals is as follows: shortly before, or upon arising in the morning, midday and late afternoon (not later than 6 P.M.). Doses may be given in 3-hour intervals, if required, to control symptoms, but not more frequently. Single doses as high as 20 mg have been given to patients, but severe and persistent systolic supine hypertension occurs at a high rate (about 45%) at this dose. In order to reduce the potential for supine hypertension during sleep, ProAmatine® should not be given after the evening meal or less than 4 hours before bedtime. Total daily doses greater than 30 mg have been tolerated by some patients, but their safety and usefulness have not been studied systematically or established. Because of the risk of supine hypertension, ProAmatine® should be continued only in patients who appear to attain symptomatic improvement during initial treatment.

The supine and standing blood pressure should be monitored regularly, and the administration of ProAmatine® should be stopped if supine blood pressure increases excessively.

Because desglymidodrine is excreted renally, dosing in patients with abnormal renal function should be cautious; although this has not been systematically studied, it is recommended that treatment of these patients be initiated using 2.5-mg doses.

Dosing in children has not been adequately studied.

Blood levels of midodrine and desglymidodrine were similar when comparing levels in patients 65 or older vs. younger than 65 and when comparing males vs. females, suggesting dose modifications for these groups are not necessary.

Renal Dosing
Renal impairment: 2.5 mg tid - gradually increasing as tolerated.

[Supplied 2.5, 5 mg, 10mg tablet]

Calculation of drip rate: 50 mg/250ml (ml/hr) = wt (kg) x 0.3 x mcg/kg/min.

Dosing (Adult):
CHF: initial loading dose, 50 mcg/kg IV over 10min, then 0.375 to 0.75 mcg/kg/min IV (Usual: 0.5 mcg/kg/min). Cardiac surgery: 15min before separation from cardiopulmonary bypass, 50 mcg/kg IV over 20 minutes followed by a continuous infusion of 0.5 mcg/kg/min IV for a minimum of 4hr.

Supplied: Injection (soln): 1 mg/ml (10 ml, 20 ml, 50 ml)

Dosage (initial): 8 to 12 mcg/min -titrate to BP (Usual target: SB:80-100 or MAP=80). Usual maintenance: 2 to 4 mcg/min. Note: doses as high as 0.5 to 1.5 mcg/kg/min for 1-10days have been used in septic shock.

Note: Norepinephrine dosage is stated in terms of norepinephrine base and intravenous formulation is norepinephrine bitartrate. Norepinephrine bitartrate 2 mg = Norepinephrine base 1 mg.

Usual range: 8-30 mcg/minute. Range used in clinical trials: 0.01-3 mcg/kg/minute.
ACLS dosage range: 0.1 - 0.5 mcg/kg/minute.
Administer into large vein to avoid the potential for extravasation.

Calculation of drip rate 8 mg/ 250 ml (ml/hr) = mcg/min x 1.875.
Supplied: Injection (soln): 1 mg/ml - 4 ml

Treat mild/moderate hypotension, also PSVT.

IV infusion: usual initial rate: 0.1 to 0.18 mg/min (100 to 180mcg/min) (titrate).
Usual maintenance rate: 40-60 mcg/min.
Maximum rate (range): infusion rates as high as 8 to10 mcg/kg/min may be required in shock.
[Usual maximum dosing range reported: 0.4 to 9.1 mcg/kg/minute ].

IV bolus therapy:  0.1 to 0.5 mg/dose every 10-15 minutes as needed (initial dose should not exceed 0.5 mg)  PSVT: 0.5 mg rapid IV push, subsequent doses may be increased in increments of 0.1 to 0.2mg.

Calculation of drip rate (40 mg/250) (ml/hr) = (mg/min) x 375.

GI hemorrhage: Continuous IV infusion: 0.5 milliunits/kg/hour (0.0005 unit/kg/hour). Double dosage as needed every 30 minutes to a maximum of 10 milliunits/kg/hour.
IV: Initial: 0.2-0.4 unit/minute, then titrate dose as needed. If bleeding stops, continue at same dose for 12 hours, taper off over 24-48 hours.
Out-of-hospital asystole (unlabeled use): Adults: 40 units IV. If spontaneous circulation is not restored in 3 minutes, then repeat dose.
Pulseless VT/VF: 40 units IV (as a single dose only). If no IV access - administer 40 units diluted with NS (to a total volume of 10 ml) endotracheally.

Vasodilatory shock/septic shock: Vasopressin may be used in patients with refractory shock despite adequate fluid resuscitation and the use of high-dose conventional catecholamines such as norepinephrine and dopamine, however, further studies are needed to determine its exact place in therapy. Current evidence does not support the use of vasopressin as a replacement for norepinephrine or dopamine as a first-line agent.

Supplied: Injection: 20 units/ml (0.5 ml, 1 ml, 10 ml)