From the Guidelines
Benzodiazepines like lorazepam or diazepam are the most appropriate choice for calming a restless patient with tachycardia. These medications can help reduce anxiety and agitation, which in turn can help lower the heart rate by decreasing sympathetic nervous system activity [/1]. The dosing for lorazepam typically ranges from 0.5-2 mg IV/IM every 4-6 hours as needed, while diazepam dosing typically ranges from 2-10 mg IV/IM.
- Key considerations when administering these medications include monitoring vital signs, respiratory status, and level of consciousness, as both benzodiazepines can cause respiratory depression and hypotension in some patients.
- It's also important to investigate and address the underlying cause of the restlessness and tachycardia, as these symptoms may be manifestations of conditions requiring specific treatment.
- While beta-blockers such as propranolol or metoprolol may be considered as alternatives or adjuncts, particularly when tachycardia is a prominent concern, the first-line treatment for calming a restless patient with tachycardia should focus on benzodiazepines due to their direct effect on the central nervous system [/1].
- Vagal maneuvers, IV adenosine, verapamil, and diltiazem, as recommended in the 2010 international consensus on cardiopulmonary resuscitation and emergency cardiovascular care science [/1], are more specifically tailored towards the termination of narrow-complex tachycardias rather than addressing restlessness and agitation directly.
From the FDA Drug Label
Metoprolol is a beta 1-selective (cardioselective) adrenergic receptor blocker. This preferential effect is not absolute, however, and at higher plasma concentrations, metoprolol also inhibits beta 2-adrenoreceptors, chiefly located in the bronchial and vascular musculature Clinical pharmacology studies have demonstrated the beta-blocking activity of metoprolol, as shown by (1) reduction in heart rate and cardiac output at rest and upon exercise, (2) reduction of systolic blood pressure upon exercise, (3) inhibition of isoproterenol-induced tachycardia, and (4) reduction of reflex orthostatic tachycardia
The patient is restless and tachycardic, and metoprolol can help reduce heart rate.
- Indication: Metoprolol can be used to reduce heart rate and systolic blood pressure.
- Mechanism of action: Metoprolol is a beta 1-selective adrenergic receptor blocker that reduces heart rate and cardiac output. As a hospitalist, you can consider giving metoprolol (PO) to help calm the patient down and reduce tachycardia 2.
From the Research
Medication Options for Restless Patients with Tachycardia
To address the issue of a restless patient with tachycardia, several medication options can be considered:
- Benzodiazepines: These can be effective in calming the patient and potentially reducing tachycardia. For example, lorazepam has been used in various studies to treat agitation and seizures 3, 4, 5.
- Haloperidol: This medication can be used in combination with lorazepam to treat psychotic agitation, as shown in a multicenter, prospective, double-blind, emergency department study 4.
- Droperidol: A butyrophenone that has been compared to lorazepam in treating methamphetamine toxicity, with results indicating it may produce more rapid and profound sedation 5.
Considerations for Benzodiazepine Use
When considering benzodiazepines, it's essential to be aware of potential effects on heart rate and rhythm:
- Benzodiazepines may increase heart rate by suppressing cardiac vagal activity, as suggested by a study on anesthetized rats 6.
- There have been cases of transient atrioventricular block after benzodiazepine exposure, highlighting the need for caution 7.
Choosing the Appropriate Medication
The choice of medication will depend on the specific patient's needs and medical history. It's crucial to weigh the potential benefits against the risks and consider alternative options:
- For patients with a history of seizure disorders, sublingual lorazepam may be an effective treatment option 3.
- In cases of psychotic agitation, the combination of lorazepam and haloperidol may be considered 4.
- For patients with methamphetamine toxicity, droperidol may be a more effective sedation option than lorazepam 5.