Can Amiodarone (antiarrhythmic medication) cause hypotension (low blood pressure)?

From the Guidelines

Amiodarone can cause hypotension, particularly when administered intravenously at a rapid rate, with an incidence of 16% as reported in a study from 2003 1. The hypotensive effect is primarily due to vasodilation and negative inotropic properties of the drug. When giving IV amiodarone, use a loading dose of 150 mg over 10 minutes (15 mg/min), followed by 1 mg/min for 6 hours, then 0.5 mg/min thereafter, as recommended in the guidelines for use and monitoring of amiodarone 1. To minimize hypotension risk, ensure adequate volume status before administration, slow the infusion rate if hypotension occurs, and monitor blood pressure continuously during IV administration. For patients who develop significant hypotension, temporarily stop the infusion, administer IV fluids, and consider vasopressors if needed. The hypotensive effect is less common with oral amiodarone, which is typically started at 800-1600 mg daily in divided doses for 1-2 weeks, then reduced to 600-800 mg daily for 1 month, followed by a maintenance dose of 200-400 mg daily. Some key points to consider when administering amiodarone include:

• Monitoring for signs of hypotension, such as dizziness or lightheadedness
• Adjusting the infusion rate or dose as needed to minimize the risk of hypotension
• Considering alternative formulations of amiodarone, such as the captisol formulation, which may have a lower risk of hypotension compared to the polysorbate formulation 1 The mechanism behind amiodarone-induced hypotension involves calcium channel blockade, alpha-adrenergic blockade, and direct myocardial depression, which collectively reduce peripheral vascular resistance and cardiac output. It is essential to weigh the benefits and risks of amiodarone therapy, particularly in patients with pre-existing cardiovascular conditions or those who are at risk of developing hypotension. In general, the benefits of amiodarone therapy, including its effectiveness in treating life-threatening arrhythmias, outweigh the risks, but careful monitoring and management of potential side effects, such as hypotension, are crucial to minimizing morbidity and mortality.

From the FDA Drug Label

5 WARNINGS AND PRECAUTIONS

Amiodarone should be administered only by physicians who are experienced in the treatment of life-threatening arrhythmias, who are thoroughly familiar with the risks and benefits of amiodarone therapy, and who have access to facilities adequate for monitoring the effectiveness and side effects of treatment Because of the long half-life of amiodarone and its metabolite desethylamiodarone, the potential for adverse reactions or interactions, as well as observed adverse effects, can persist following amiodarone withdrawal. 5. 1 Hypotension Hypotension is the most common adverse reaction seen with intravenous amiodarone. In clinical trials, treatment-emergent, drug-related hypotension was reported as an adverse effect in 288 (16%) of 1836 patients treated with intravenous amiodarone Clinically significant hypotension during infusions was seen most often in the first several hours of treatment and was not dose related, but appeared to be related to the rate of infusion. Hypotension necessitating alterations in intravenous amiodarone therapy was reported in 3% of patients, with permanent discontinuation required in less than 2% of patients Treat hypotension initially by slowing the infusion; additional standard therapy may be needed, including the following: vasopressor drugs, positive inotropic agents, and volume expansion. Monitor the initial rate of infusion closely and do not exceed the recommended rate [see Dosage and Administration (2)] In some cases, hypotension may be refractory and result in a fatal outcome [see Adverse Reactions ( 6-6.2)].

• Hypotension is a common adverse reaction associated with intravenous amiodarone therapy, occurring in 16% of patients in clinical trials 2.
• It is recommended to treat hypotension initially by slowing the infusion rate, and additional standard therapy may be needed, including vasopressor drugs, positive inotropic agents, and volume expansion.
• In some cases, hypotension may be refractory and result in a fatal outcome.

From the Research

Amiodarone and Hypotension

• Amiodarone, an antiarrhythmic medication, can cause hypotension (low blood pressure) as evidenced by several studies 3, 4, 5.
• A study published in 2010 found that intravenous amiodarone-induced hypotension persists beyond the loading dose and into the maintenance infusion period 3.
• Another study from 2015 reported a case of a male patient who developed severe hypotension related to amiodarone and required inotropic support along with rapid-sequence intubation 4.
• In a multicenter protocol study published in 1996, four patients experienced mild hypotension during the amiodarone bolus, but no proarrhythmic effects were observed 5.

Mechanism and Management

• The hypotensive effect of intravenous amiodarone is attributed to the cosolvents in the formulation, and not solely related to the initial loading dose 3.
• Administration of a cosolvent-free formulation of amiodarone (PM101) caused no haemodynamic effects, indicating that the cardiodepressant effects of intravenous amiodarone were due to its cosolvents 3.
• Management of hypotension caused by amiodarone may involve slowing the rate of administration, and in severe cases, inotropic support and rapid-sequence intubation may be required 4.