Drug Guide

Generic Name

Trimethaphan Camsylate

Brand Names Arfonad

Classification

Therapeutic: Antihypertensive, Neuromuscular Blocker

Pharmacological: Nicotinic Cholinergic Antagonist

FDA Approved Indications

  • Control of blood pressure during hypertensive emergencies, especially during surgery or anesthesia

Mechanism of Action

Trimethaphan blocks nicotinic acetylcholine receptors at autonomic ganglia, leading to a rapid and reversible blockade of autonomic transmission, resulting in vasodilation and decreased blood pressure.

Dosage and Administration

Adult: Initial doses typically range from 15-30 mg IV, titrated based on blood pressure response.

Pediatric: Dosing in pediatric patients is individualized; consult specific pediatric guidelines.

Geriatric: Start at lower doses with careful titration due to increased sensitivity.

Renal Impairment: Adjust dose based on clinical response and tolerability.

Hepatic Impairment: No specific adjustment; use caution as hepatic metabolism may be affected.

Pharmacokinetics

Absorption: Administered intravenously; rapid onset.

Distribution: Widely distributed, crosses the blood-brain barrier minimally.

Metabolism: Metabolized in the liver.

Excretion: Excreted primarily via the kidneys.

Half Life: Approximately 4-8 minutes, depending on dosage and blood flow.

Contraindications

  • Known hypersensitivity to trimethaphan or related compounds.
  • Obstructive coronary artery disease.
  • Lactation.

Precautions

  • Use with caution in patients with cerebral hemorrhage, impaired kidney or liver function, or arrhythmias. Monitor closely for cardiovascular stability during therapy.

Adverse Reactions - Common

  • Hypotension (Common)
  • Tachycardia (Common)
  • Reflex tachycardia and arrhythmias (Possible)

Adverse Reactions - Serious

  • Seizures (rare) (Rare)
  • Anaphylaxis (rare) (Rare)

Drug-Drug Interactions

  • Other antihypertensives, especially agents affecting autonomic function.
  • Agents that prolong QT interval.

Drug-Food Interactions

N/A

Drug-Herb Interactions

N/A

Nursing Implications

Assessment: Monitor blood pressure, heart rate, and rhythm closely during administration.

Diagnoses:

  • Ineffective tissue perfusion related to hypotension.
  • Risk for decreased cardiac output.

Implementation: Administer IV slowly and titrate to desired blood pressure. Have resuscitative equipment ready.

Evaluation: Assess if blood pressure stabilizes within target range without adverse effects.

Patient/Family Teaching

  • Report any symptoms of dizziness, fainting, or rapid heartbeat.
  • Follow instructions on medication administration and monitoring.

Special Considerations

Black Box Warnings:

  • Hypotension and cardiac arrhythmias can be severe; continuous monitoring required.

Genetic Factors: No specific genetic considerations.

Lab Test Interference: May affect blood pressure readings during administration.

Overdose Management

Signs/Symptoms: Severe hypotension, bradycardia or tachycardia, arrhythmias.

Treatment: Discontinue drug; provide supportive care including vasopressors or anticholinergics as indicated; manage arrhythmias per ACLS protocols.

Storage and Handling

Storage: Store at room temperature, protected from light.

Stability: Stable until expiration date when stored properly.

🛡️ 5 Critical Medication Safety Tips for Nurses

1

Triple-Check High-Risk Medications

Always have another nurse verify insulin, heparin, warfarin, and chemotherapy drugs. These "high-alert" medications cause the most serious errors. Check concentration, dose calculation, and pump settings twice.

2

Know Look-Alike, Sound-Alike Drugs

Common mix-ups: hydromorphone/morphine, Celebrex/Celexa, Zyprexa/Zyrtec. Always use BOTH generic and brand names, read labels twice, and use barcode scanning when available. One wrong letter can be fatal.

3

Assess Before AND After Giving Meds

Check vitals before cardiac meds, pain levels before analgesics, and blood glucose before insulin. Always reassess within 30 minutes to evaluate effectiveness and watch for adverse reactions.

4

Watch for Drug Interactions

Common dangerous combinations: warfarin + aspirin (bleeding), ACE inhibitors + potassium (hyperkalemia), digoxin + diuretics (toxicity). Always check drug interactions before administering new medications.

5

Educate Your Patients

Teach patients medication names, purposes, major side effects, and what to report. Informed patients catch errors and improve compliance. Always encourage questions - an educated patient is a safer patient.

⚡ Remember: When in doubt, don't give it out! It's always safer to double-check than regret later.

⚠️ Medical Disclaimer

This drug guide is for educational purposes only and is NOT intended for clinical use. Always consult current prescribing information, healthcare providers, and institutional protocols before administering any medication. Do not use this information for patient care decisions.