From the Guidelines
Hypotension is a relative contraindication to adenosine administration. Caution should be exercised when giving adenosine to patients with existing low blood pressure, as the medication can cause transient hypotension that may worsen the patient's hemodynamic status. Adenosine, typically given as a 6mg rapid IV bolus followed by a 12mg dose if needed for supraventricular tachycardia (SVT), works by temporarily blocking AV node conduction and can cause brief vasodilation. This vasodilatory effect may exacerbate pre-existing hypotension, potentially leading to hemodynamic compromise.
In patients with hypotension, clinicians should consider alternative treatments for SVT such as:
- Vagal maneuvers
- Calcium channel blockers like diltiazem (if blood pressure permits)
- Electrical cardioversion if the patient is unstable
If adenosine must be used in a hypotensive patient, careful monitoring of blood pressure and preparation for supportive measures including fluid boluses and vasopressors is essential. The decision to use adenosine in hypotensive patients should be based on a risk-benefit assessment, considering the severity of the hypotension and the urgency of treating the tachyarrhythmia, as recommended by the 2015 ACC/AHA/HRS guideline for the management of adult patients with supraventricular tachycardia 1.
Key points to consider when using adenosine in patients with hypotension include:
- The potential for worsening hypotension
- The need for careful monitoring and supportive measures
- The importance of a risk-benefit assessment in deciding whether to use adenosine in hypotensive patients.
It is also important to note that other treatment options, such as vagal maneuvers and calcium channel blockers, may be preferred in patients with hypotension, as they may be less likely to exacerbate low blood pressure 1.
From the FDA Drug Label
5.4 Hypotension Adenosine injection is a potent peripheral vasodilator and can induce significant hypotension. The risk of serious hypotension may be higher in patients with autonomic dysfunction, hypovolemia, stenotic valvular heart disease, pericarditis or pericardial effusions, or stenotic carotid artery disease with cerebrovascular insufficiency Discontinue adenosine injection in any patient who develops persistent or symptomatic hypotension.
Hypotension is not a contraindication to adenosine, but rather a condition where caution is advised and where the drug should be discontinued if persistent or symptomatic hypotension develops 2.
From the Research
Hypotension and Adenosine
- Hypotension is not a contraindication to adenosine, but it can be a side effect of adenosine administration 3, 4, 5.
- Studies have shown that adenosine can cause hypotension, but the incidence is generally lower compared to calcium channel antagonists such as verapamil 4, 5.
- The rate of hypotension associated with adenosine is reported to be around 0-0.6% 4, 5, while verapamil has a higher rate of causing hypotension, around 3-3.7% 4, 5.
Adenosine and Coronary Microcirculation
- Adenosine infusion can produce coronary and systemic vasodilatation, leading to systemic hypotension 6.
- The degree of adenosine-induced hypotension is associated with coronary microcirculatory resistance, with lower resistance values observed in patients with profound hypotension 6.
- Obesity is an independent predictor of profound adenosine-induced hypotension, and body mass index is associated with the degree of hypotension 6.
Clinical Implications
- The decision to use adenosine or calcium channel antagonists for the treatment of supraventricular tachycardia should be made on a case-by-case basis, taking into account the patient's individual characteristics and medical history 3, 4, 5.
- Patients should be fully informed of the potential risks and side effects of adenosine and calcium channel antagonists, including the risk of hypotension 4, 5.