Administer a lorazepam challenge with 1-2 mg IV and observe for clinical response within 30 minutes, as a positive response confirms the diagnosis and guides ongoing benzodiazepine treatment

If the patient demonstrates improvement in motor signs, plan scheduled lorazepam 1-2 mg every 8 hours with titration based on clinical response. Concurrently hold any antipsychotic medications and monitor vitals, CK levels, and hydration status closely. The lorazepam challenge test is the standard initial intervention for catatonia. A positive response (reduction in catatonic signs within minutes to hours) both confirms the diagnosis and establishes the treatment approach. Scheduled benzodiazepines with titration are the first-line pharmacologic treatment. Holding antipsychotics is critical, as they can worsen catatonia and increase the risk of progression to malignant catatonia or neuroleptic malignant syndrome.

Initiate an emergent electroconvulsive therapy consultation given the severity of the presentation and elevated CK, as ECT is the most definitive treatment for catatonia and should not be delayed

Plan for bilateral electrode placement with treatments scheduled three times per week. Continue monitoring CK levels and ensure adequate IV hydration while awaiting the first ECT session. While ECT is highly effective for catatonia and is considered the definitive treatment, it is typically reserved for cases that fail to respond to an adequate benzodiazepine trial or when malignant catatonia is present. The initial step should be a lorazepam challenge to confirm the diagnosis and assess benzodiazepine responsiveness before pursuing ECT. Proceeding directly to ECT without trialing lorazepam first does not follow standard treatment algorithms.

Administer haloperidol 5 mg IM to address the acute psychomotor disturbance, as the patient's bipolar history suggests an underlying psychotic process driving the catatonic features

Plan to reassess in 2 hours and repeat the dose if motor symptoms persist. Concurrently order IV fluids for hydration and serial CK monitoring to evaluate for rhabdomyolysis risk. Administering an antipsychotic such as haloperidol to a patient with catatonia is contraindicated as an initial intervention because it can significantly worsen catatonic symptoms and precipitate malignant catatonia or neuroleptic malignant syndrome. The elevated CK and tachycardia already suggest early autonomic instability, making antipsychotic administration particularly dangerous in this context. Benzodiazepines are the appropriate first-line treatment.

Initiate amantadine 100 mg twice daily via nasogastric tube given the patient's inability to take oral medications, as NMDA receptor antagonism has demonstrated efficacy in catatonia

Plan to titrate to 200 mg twice daily over the next 48 hours if no clinical improvement is observed. Simultaneously order a comprehensive metabolic panel, thyroid studies, and neuroimaging to rule out medical etiologies. While amantadine and other NMDA antagonists such as memantine have some evidence for adjunctive use in catatonia, they are not first-line treatment and should not replace the standard lorazepam challenge. The level of evidence supporting amantadine in catatonia is significantly weaker compared to benzodiazepines. Beginning with a lorazepam challenge is essential for both confirming the diagnosis and initiating effective treatment.