Droxidopa (Capsule) 100mg

Droxidopa is a sympathomimetic agent used to manage symptoms of neurogenic orthostatic hypotension (nOH).

• Neurogenic orthostatic hypotension due to primary autonomic failure: Helps alleviate orthostatic dizziness, lightheadedness, or the feeling of impending blackout in patients with conditions such as Parkinson's disease, multiple system atrophy, and pure autonomic failure.
• Dopamine beta-hydroxylase deficiency: Treats symptoms associated with this rare genetic disorder that affects the production of norepinephrine.
• Non-diabetic autonomic neuropathy: Addresses symptoms in patients with autonomic neuropathy not caused by diabetes.

• Droxidopa is converted to norepinephrine by the enzyme aromatic L-amino acid decarboxylase. This increases peripheral norepinephrine levels, which helps raise blood pressure and alleviate symptoms of neurogenic orthostatic hypotension. The drug induces small and transient rises in plasma norepinephrine, thereby improving blood pressure regulation in patients with nOH.

Droxidopa may cause several side effects, ranging from common to serious.

Common Side Effects

• Headache: A frequent side effect reported by patients taking droxidopa.
• Dizziness: Commonly experienced due to the drug's effect on blood pressure regulation.
• Nausea: A gastrointestinal side effect that may occur during treatment.
• Hypertension: Elevated blood pressure is a common adverse reaction.
• Syncope: Fainting spells may occur, particularly in elderly patients.
• Urinary tract infections: More common in elderly patients.
• Falls: Increased risk of falls due to dizziness or syncope.

Serious or Rare Side Effects

• Supine hypertension: Elevated blood pressure while lying down, which may increase the risk of cardiovascular events.
• Ischemic heart disease: Droxidopa may exacerbate existing heart conditions.
• Arrhythmias: Abnormal heart rhythms may occur as a result of the drug's effects on the cardiovascular system.
• Congestive heart failure: The drug may worsen pre-existing heart failure.
• Hyperpyrexia and confusion: Rare but serious side effects resembling neuroleptic malignant syndrome (NMS).
• Allergic reactions: Hypersensitivity reactions, including anaphylaxis, angioedema, and rash, have been reported.

Droxidopa should be used with caution in certain patient populations and conditions.

• Monitor supine blood pressure: Regularly check blood pressure while lying down to manage the risk of supine hypertension.
• Elevate the head of the bed: This helps reduce the risk of supine hypertension during sleep.
• Caution in heart disease: Patients with ischemic heart disease, arrhythmias, or congestive heart failure should be closely monitored.
• Hypersensitivity: Discontinue the drug if signs of an allergic reaction occur.
• Pregnancy and breastfeeding: Consult a healthcare provider before use, as the safety in these populations is not well established.
• Renal impairment: Droxidopa is not recommended in patients with severe kidney damage (GFR less than 30 mL/min).
• Store at room temperature: Keep the capsules at 20°C-25°C, protect from moisture, and store in the original packaging.

Droxidopa may interact with other medications, potentially affecting its efficacy or increasing the risk of side effects.

Major Interactions (Avoid)

• Monoamine oxidase inhibitors (MAOIs): Concomitant use may lead to severe hypertension.
• Non-selective monoamine oxidase inhibitors (MAOIs): Avoid using droxidopa with these drugs to prevent dangerous increases in blood pressure.
• Linezolid: This antibiotic has MAOI properties and should not be used with droxidopa.
• Methylthioninium chloride (methylene blue injection): Avoid concurrent use due to the risk of hypertension.

Moderate Interactions (Monitor Closely)

• Levodopa: Observe patients carefully when changing the dosage of droxidopa or levodopa, as it may lead to hyperpyrexia and confusion.
• Other sympathomimetic drugs: Monitor blood pressure closely when using droxidopa with other drugs that affect the sympathetic nervous system.
• Drugs metabolized by COMT: Droxidopa may interfere with the metabolism of these drugs, requiring careful monitoring.