From the Guidelines
Both codeine and tramadol can cause bradycardia, although this side effect is relatively uncommon. These opioid analgesics work by binding to opioid receptors in the central nervous system, which can affect the autonomic nervous system that regulates heart rate. Specifically, they can increase parasympathetic (vagal) tone and decrease sympathetic stimulation, potentially leading to a slowing of the heart rate. The risk of bradycardia is generally higher with stronger opioids like morphine or fentanyl than with codeine or tramadol, which are considered weaker opioids. The risk increases with higher doses, in elderly patients, in those with pre-existing cardiac conditions, and when these medications are combined with other drugs that can slow heart rate (such as beta-blockers or calcium channel blockers) 1. Some key points to consider when prescribing these medications include:
- Monitoring heart rate and blood pressure, especially in patients with pre-existing cardiac conditions
- Being aware of potential drug-drug interactions that may increase the risk of bradycardia
- Starting with low doses and titrating as needed to minimize the risk of adverse effects
- Educating patients on the symptoms of bradycardia, such as dizziness, weakness, fatigue, and fainting, and advising them to seek medical attention if these symptoms occur. It's also important to note that while the evidence from 1 and 1 provides guidance on the use of tramadol and other opioids, the most recent and highest quality study 1 highlights the importance of considering potential drug-drug interactions and monitoring for cardiac effects when using these medications.
From the FDA Drug Label
At therapeutic doses, tramadol hydrochloride has no effect on heart rate, left-ventricular function or cardiac index. Acute overdosage with tramadol can be manifested by ... bradycardia, ...
Bradycardia is listed as a potential symptom of tramadol overdose, but at therapeutic doses, tramadol is not shown to affect heart rate. There is no information about codeine in the provided drug labels. 2 2
From the Research
Opioid Analgesics and Bradycardia
- Codeine and tramadol are opioid analgesics used to treat pain, but their effects on heart rate, specifically bradycardia (abnormally slow heart rate), need to be considered.
- According to 3, opioids can lead to bradycardia and vasodilation, which can rarely cause edema, hypotension, orthostatic hypotension, and syncope when used at analgesic doses.
- However, the studies 4, 5, 6, and 7 do not specifically focus on the effects of codeine or tramadol on heart rate or bradycardia.
- While 3 mentions that opioids can cause bradycardia, it does not provide specific information on codeine or tramadol.
- The other studies 4, 5, 6, and 7 discuss the cardiovascular risks associated with tramadol and codeine, but they do not provide direct evidence on the incidence of bradycardia.
Comparison of Codeine and Tramadol
- The study 7 compares the short-term risk of cardiovascular events, including myocardial infarction, unstable angina, and ischemic stroke, between tramadol and codeine users, but it does not report on bradycardia specifically.
- The study 4 examines the association of tramadol with the risk of myocardial infarction among patients with osteoarthritis, but it does not provide information on bradycardia.
- The studies 5 and 6 discuss the pharmacology and clinical utility of tramadol and codeine, but they do not provide direct evidence on the effects of these medications on heart rate or bradycardia.
Cardiovascular Effects
- The study 3 highlights the importance of careful patient selection and diligent monitoring when using opioids, including codeine and tramadol, due to their potential cardiovascular effects.
- The study 7 finds that short-term use of tramadol, compared with codeine, is not associated with an increased risk of cardiac events among patients with non-cancer pain.
- However, the studies do not provide conclusive evidence on the specific effects of codeine or tramadol on heart rate or bradycardia.