Interventional psychiatry (Part 1)

Aducanumab and lecanemab are generally not covered by insurance and typically cost >$26,000 annually. Both are administered by IV infusion once a month. More monoclonal antibody medications for treating early Alzheimer disease are in the late stages of development, most notably donanebab.²⁴ Observations during clinical trials found that in the later stages of Alzheimer disease, forceful removal of plaques by the autoimmune process damages neurons, while in less dense deposits of early dementia such removal is not harmful to the cells and prevents amyloid buildup.

Brexanolone

Brexanolone is an aqueous formulation of allopregnanolone, a major metabolite of progesterone and a positive allosteric modulator of GABA-A receptors.²⁵ Its levels are maximal at the end of the third trimester of pregnancy and fall rapidly following delivery. Research showed a 3-day infusion was rapidly and significantly effective for treating postpartum depression²⁶ and brexanolone received FDA approval for this indication in March 2019.²⁷ However, various administrative, economic, insurance, and other hurdles make it difficult for patients to access this treatment. Despite its rapid onset of action (usually 48 hours), brexanolone takes an average of 15 days to go through the prior authorization process.²⁸ In addition to the need for prior authorization, the main impediment to the use of brexanolone is the 3-day infusion schedule, which greatly magnifies the cost but is partially circumvented by the availability of dedicated outpatient centers.

Magnesium

Magnesium is on the World Health Organization’s Model List of Essential Medicines.²⁹ There has been extensive research on the use of magnesium sulfate for psychiatric indications, especially for depression.³⁰ Magnesium functions similarly to calcium channel blockers by competitively blocking intracellular calcium channels, decreasing calcium availability, and inhibiting smooth muscle contractility.³¹ It also competes with calcium at the motor end plate, reducing excitation by inhibiting the release of acetylcholine.³² This property is used for high-dose IV magnesium treatment of impending preterm labor in obstetrics. Magnesium sulfate is the drug of choice in treating eclamptic seizures and preventing seizures in severe preeclampsia or gestational hypertension with severe features.³³ It is also used to treat torsade de pointes, severe asthma exacerbations, constipation, and barium poisoning.³⁴ Beneficial use in asthma treatment³⁵ and the treatment of migraine³⁶ have also been reported.

IV magnesium in myocardial infarction may be harmful,³⁷ though outside of acute cardiac events, magnesium is found to be safe.³⁸

Oral magnesium sulfate is a common over-the-counter anxiety remedy. As a general cell stabilizer (mediated by the reduction of intracellular calcium), magnesium is potentially beneficial outside of its muscle-relaxing properties, although muscle relaxing can benefit anxious patients. It is used to treat anxiety,³⁹ alcohol withdrawal,⁴⁰ and fear.⁴¹ Low magnesium blood levels are found in patients with depression, schizophrenia,⁴² and attention-deficit/hyperactivity disorder.⁴³ However, it is important to note that the therapeutic effect of magnesium when treating anxiety and headache is independent of preinfusion magnesium blood levels.⁴³

Continue to: The efficacy of oral magnesium...