droxidopa

(drox-i-doe-pa),

Northera

(trade name)

Classification

Therapeutic: temporary class
Pharmacologic: adrenergics

Indications

Treatment of orthostatic dizziness, lightheadedness or feeling of impending blackout associated with symptomatic neurogenic orthostatic hypotension due to primary autonomic failure (Parkinson's disease, multiple system atrophy), dopamine beta-hydroxylase deficiency or non-diabetic autonomic neuropathy.

Action

Acts as a synthetic precursor that is converted by dopa decarboxylase to norepinephrine which produces peripheral arterial and venous vasocontriction. Result is increased blood pressure.

Therapeutic effects

Increased blood pressure with decreased symptoms of orthostatic dizziness.

Pharmacokinetics

Absorption: Systemic absorption follows oral administration.Distribution: Crosses the blood-brain barrier.Metabolism and Excretion: Metabolized via catecholamine pathway; metabolites other than norepinephrine do not contribute to activity. 75% excreted by kidneys as parent drug and metabolites.Half-life: 2.5 hr.

Time/action profile (↑ blood pressure)

ROUTE	ONSET	PEAK	DURATION
PO	unknown	1–4 hr	unknown

Contraindications/Precautions

Contraindicated in: Hypersensitivity to droxidopa or tartrazine (FD+C No. 5 [cross sensitivity between aspirin and FD+C No. 5 may occur); CCr <30 mL/min; Lactation: Discontinue droxidopa or discontinue breastfeeding.Use Cautiously in: Hypertension (should be controlled prior to treatment); Mild to moderate renal impairment (↑ risk of adverse reactions); History of cardiovascular disease (may exacerbate hypertension, ischemic heart disease, arrhythmias or CHF); Geriatric: Elderly patients may be more sensitive to drug effects; Obstetric: Safe use during pregnancy has not been established; Pediatric: Safe and effective use in children has not been established.

Adverse Reactions/Side Effects

Central nervous system

confusion
dizziness
fatigue
headache

Cardiovascular

arrhythmias (life-threatening)
CHF (life-threatening)
myocardial ischemia (life-threatening)
supine hypertension

Gastrointestinal

nausea

Miscellaneous

hyperpyrexia

Interactions

Drug-Drug interaction

↑ risk of supine hypertension with other agents that ↑ blood pressure including ephedrine, norepinephrine, midodrine, pseudoephedrine, and triptans.Concurrent use of DOPA decarboxylase inhibitors may require dose adjustments.

Route/Dosage

Oral (Adults) 100 mg three times daily, may be ↑ by 100 mg three times daily up to 600 mg three times daily (last dose should be given at least 3 hr prior to bedtime).

Availability

Capsules (contain tartrazine): 100 mg, 200 mg, 300 mg

Nursing implications

Nursing assessment

Monitor blood pressure prior to and during therapy; more frequently during dose increases. Measure blood pressure in supine position and while head of bed is elevated; lessens risks of supine hypertension. If supine hypertension cannot be managed by elevating head of bed, reduce or discontinue droxidopa. Poorly managed supine hypertension may increase risk for cardiovascular events.
Monitor for symptom complex resembling neuroleptic malignant syndrome (fever, muscle rigidity, involuntary movements, altered consciousness, mental status changes) when dose is changed or when concomitant levodopa is abruptly reduced or discontinued, especially if patient is receiving neuroleptics. Syndrome is rare but potentially fatal.

Potential Nursing Diagnoses

Deficient knowledge, related to disease process and medication regimen (Patient/Family Teaching)

Implementation

Oral: Administer upon arising in the morning, midday, and in late afternoon at least 3 hr prior to bedtime to reduce risk of supine hypertension during sleep. Swallow capsule whole; do not open, crush or chew.
- May be administered without regard to food, but should be consistent each dose.

Patient/Family Teaching

Instruct patient to take droxidopa as directed. If dose is missed, omit and take next dose at scheduled time; do not double doses.
Advise patient to raise head of bed when resting or sleeping.
Instruct patient how to take blood pressure and manage elevations.
Advise female patient to notify health care professional if pregnancy is planned or suspected or if breastfeeding.

Evaluation/Desired Outcomes

Increased blood pressure with decreased symptoms of orthostatic dizziness.