Nurses Compass
Drug Guide
Guanadrel Sulfate
Classification
Therapeutic: Antihypertensive, Sympatholytic agent
Pharmacological: Adrenergic neuron blocker
FDA Approved Indications
- Hypertension (used to be approved but may no longer be in common use; consult current guidelines)
Mechanism of Action
Guanadrel sulfate inhibits sympathetic postganglionic neurons, reducing norepinephrine release, leading to decreased sympathetic activity and lowering blood pressure.
Dosage and Administration
Adult: Typically 20 mg twice daily, adjusted based on response.
Pediatric: Not generally used in pediatric populations.
Geriatric: Initial dose may be lower; monitor for orthostatic hypotension.
Renal Impairment: Adjust dose based on renal function; closely monitor blood pressure.
Hepatic Impairment: Use with caution; no specific adjustment established.
Pharmacokinetics
Absorption: Well absorbed from the gastrointestinal tract.
Distribution: Widely distributed; crosses the blood-brain barrier to some extent.
Metabolism: Minor hepatic metabolism, primarily excreted unchanged.
Excretion: Primarily via urine.
Half Life: Approximately 7-8 hours.
Contraindications
- History of hypersensitivity to guanadrel sulfate or related drugs.
Precautions
- Use with caution in patients with orthostatic hypotension, renal impairment, or cerebrovascular disease.
Adverse Reactions - Common
- Postural hypotension (Frequent)
- Gastrointestinal disturbances (nausea, diarrhea) (Occasional)
Adverse Reactions - Serious
- Agranulocytosis, hemolytic anemia (Rare)
- Severe hypotension or hypertensive crisis (Rare)
Drug-Drug Interactions
- Other antihypertensives, sympathomimetics, MAO inhibitors
Drug-Food Interactions
N/ADrug-Herb Interactions
N/ANursing Implications
Assessment: Monitor blood pressure and heart rate regularly. Watch for signs of hypotension and adverse hematologic reactions.
Diagnoses:
- Risk for falls related to hypotension.
- Impaired tissue perfusion.
Implementation: Administer as ordered, typically in divided doses. Educate patient on symptoms of hypotension.
Evaluation: Assess effectiveness via blood pressure measurements and symptom control.
Patient/Family Teaching
- Take medication exactly as prescribed.
- Rise slowly from sitting or lying position to prevent dizziness.
- Report symptoms of weakness, sore throat, fever, or unusual bleeding.
Special Considerations
Black Box Warnings:
- Potential for hematologic reactions such as agranulocytosis; monitor blood counts regularly.
Genetic Factors: None specific.
Lab Test Interference: May affect blood glucose or hematologic tests.
Overdose Management
Signs/Symptoms: Se severe hypotension, dizziness, bradycardia.
Treatment: Supportive care, vasopressors if needed, and IV fluids. Remove the offending agent.
Storage and Handling
Storage: Store at room temperature, protected from moisture and light.
Stability: Stable for 2-3 years under proper conditions.