Overview
11 DESCRIPTION Droxidopa capsules contain droxidopa, which is a synthetic amino acid precursor of norepinephrine, for oral administration. Chemically, droxidopa is (-)-threo-3-(3,4-Dihydroxyphenyl)-L-serine. It has the following structural formula: Droxidopa is white to light brown crystals or crystalline powder.
Mechanism of Action
12 CLINICAL PHARMACOLOGY 12.1 Mechanism of Action The exact mechanism of action of droxidopa in the treatment of neurogenic orthostatic hypotension is unknown. Droxidopa is a synthetic amino acid analog that is directly metabolized to norepinephrine by dopa-decarboxylase, which is extensively distributed throughout the body. Droxidopa is believed to exert its pharmacological effects through norepinephrine and not through the parent molecule or other metabolites. Norepinephrine increases blood pressure by inducing peripheral arterial and venous vasoconstriction. Droxidopa in humans induces small and transient rises in plasma norepinephrine. 12.2 Pharmacodynamics Peak droxidopa plasma concentrations are associated with increases in systolic and diastolic blood pressures.
Indications
- 1 INDICATIONS AND USAGE Droxidopa capsules indicated for the treatment of orthostatic dizziness, lightheadedness, or the “feeling that you are about to black out” in adult patients with symptomatic neurogenic orthostatic hypotension (nOH) caused by primary autonomic failure (Parkinson's disease [PD], multiple system atrophy, and pure autonomic failure), dopamine beta-hydroxylase deficiency, and non-diabetic autonomic neuropathy. Effectiveness beyond 2 weeks of treatment has not been established. The continued effectiveness of droxidopa capsules should be assessed periodically.
Common Doses
- 100 mg
- 600 mg
- 800 mg
Dosage
2 DOSAGE AND ADMINISTRATION • Starting dose is 100 mg three times during the day (2.1) • Titrate by 100 mg three times daily, up to a maximum dose of 600 mg three times daily (2.1) • Take consistently with or without food (2.1) • To reduce the potential for supine hypertension, elevate the head of the bed and give the last dose at least 3 hours prior to bedtime (2.1) • Take droxidopa capsule whole (2.1) 2.1 Dosing Information The recommended starting dose of droxidopa capsules is 100 mg, taken orally three times daily: upon arising in the morning, at midday, and in the late afternoon at least...
Black Box Warning
WARNING: SUPINE HYPERTENSION WARNING: SUPINE HYPERTENSION See full prescribing information for complete boxed warning. Monitor supine blood pressure prior to and during treatment and more frequently when increasing doses. Elevating the head of the bed lessens the risk of supine hypertension, and blood pressure should be measured in this position. If supine hypertension cannot be managed by elevation of the head of the bed, reduce or discontinue droxidopa [see Warnings and Precautions (5.1) ].
Contraindications
- 4 CONTRAINDICATIONS Droxidopa is contraindicated in patients who have a history of hypersensitivity to the drug or its ingredients [see Warnings and Precautions (5.4) ]. History of hypersensitivity to the drug or its ingredients
Side Effects
- 6 ADVERSE REACTIONS The following adverse reactions with droxidopa are included in more detail in the Warnings and Precautions section of the label: • Supine Hypertension [see Warnings and Precautions (5.1) ] • Hyperpyrexia and Confusion [see Warnings and Precautions (5.2) ] • May exacerbate existing ischemic heart disease, arrhythmias, and congestive heart failure [see Warnings and Precautions (5.3) ] The most common adverse reactions (>5% and ≥3% compared to placebo) are headache, dizziness, nausea, and hypertension (6.
Interactions
- 7 DRUG INTERACTIONS Use of DOPA decarboxylase inhibitors may require dose adjustments for droxidopa (7.2) 7.1 Drugs that Increase Blood Pressure Administering droxidopa in combination with other agents that increase blood pressure (e.g., norepinephrine, ephedrine, midodrine, and triptans) would be expected to increase the risk for supine hypertension. 7.2 Parkinson’s Medications Dopa-decarboxylase inhibitors may require dose adjustments for droxidopa. 7.