What is the interaction between magnesium supplements and Seroquel (quetiapine)?

Magnesium and Seroquel (Quetiapine) Interaction

Magnesium supplements can be safely taken with Seroquel (quetiapine) without significant drug interactions, but timing of administration should be separated by at least 2 hours to avoid potential absorption issues if magnesium is given in high doses intravenously or with other medications.

No Direct Pharmacological Interaction

• There is no clinically significant pharmacokinetic or pharmacodynamic interaction between magnesium and quetiapine 1, 2
• Quetiapine is primarily metabolized through CYP3A4 enzymes, and magnesium does not affect this metabolic pathway 3
• Magnesium does not alter quetiapine's receptor binding profile or its effects on dopamine and serotonin systems 2

Potential Benefits of Combination

• Magnesium supplementation may actually reduce movement side effects associated with antipsychotic medications, though this evidence comes primarily from studies with typical antipsychotics like haloperidol rather than atypical agents like quetiapine 4
• In patients with schizophrenia treated with antipsychotics, magnesium levels in erythrocytes tend to be decreased, and antipsychotic treatment can increase magnesium concentrations 5
• Magnesium supplementation prevented haloperidol-induced orofacial dyskinesia and catalepsy in animal studies by reducing oxidative stress in brain regions 4

Timing Considerations with Other Medications

• If quetiapine is prescribed alongside fluoroquinolone antibiotics (like ciprofloxacin), magnesium-containing preparations should be taken at least 1-2 hours before or 4 hours after the antibiotic to avoid reduced antibiotic absorption 6
• This timing separation applies to magnesium-containing antacids, supplements, or mineral-fortified products 6

Safety Profile

• Magnesium sulfate infusions are considered safe with serum levels below 4 mg/dL, with minimal side effects limited to flushing and light-headedness 6
• Magnesium toxicity (areflexia progressing to respiratory depression) only occurs at concentrations of 6-8 mEq/L, which is unlikely with standard supplementation doses 6
• Quetiapine has an excellent tolerability profile with minimal effects on extrapyramidal symptoms, prolactin levels, and body weight, making it compatible with adjunctive therapies like magnesium 1, 2

Clinical Recommendations

• Oral magnesium supplements can be taken concurrently with quetiapine without dose adjustments 3
• Monitor for excessive sedation if multiple CNS-active medications are used together, though magnesium itself is non-sedating 6
• In patients with renal impairment taking quetiapine, standard magnesium supplementation remains safe as quetiapine pharmacokinetics are not significantly altered by renal dysfunction 3
• In patients with hepatic impairment (alcoholic cirrhosis), quetiapine dose escalation should be performed cautiously due to inter-subject variability in clearance, but magnesium supplementation does not compound this concern 3

Common Pitfall to Avoid

• Do not confuse the lack of interaction between magnesium and quetiapine with the significant interactions that exist between magnesium and fluoroquinolone antibiotics 6
• If a patient on quetiapine requires antibiotic therapy with a fluoroquinolone and is taking magnesium supplements, temporal separation of dosing is essential for the antibiotic's efficacy, not because of the quetiapine 6