Ark Shell — Safety & Interactions
Wa Leng Zi · Concha Arcae
Contraindications
- Spleen-Stomach Deficiency Cold with no acid — neutral-salty nature; antacid action inappropriate in hypochlorhydria (insufficient gastric acid); may impair digestion in cold-deficient patients
- Absence of Phlegm-Stasis accumulation — mass-softening action requires a pathological target; do not use as a general tonic
Cautions
- Standard dose: 9–15 g raw shell in decoction (decocted first 30 min); 1–3 g calcined powder (Dan Wa Leng Zi) for antacid and haemostatic use; taken before meals for gastric acid conditions
- Calcium-containing antacids: concurrent use with other calcium carbonate antacids (Tums, chalk) may cause milk-alkali syndrome at high doses; do not combine with multiple calcium sources long-term
- Drug separation from absorption-sensitive medications: calcium carbonate chelates fluoroquinolone antibiotics, tetracyclines, and bisphosphonates — administer Wa Leng Zi 2 hours apart from these drugs
- Thyroid hormone absorption: calcium carbonate reduces levothyroxine absorption; separate administration by ≥4 hours
Drug Interactions
| Drug Class / Substrate | Mechanism | Severity | Source |
|---|---|---|---|
| Fluoroquinolone antibiotics (ciprofloxacin, levofloxacin) — calcium chelation reduces antibiotic bioavailability by 50–70%; take antibiotic 2 hours before or 6 hours after Wa Leng Zi | |||
| Tetracycline antibiotics — calcium chelation; same separation protocol as fluoroquinolones | |||
| Levothyroxine — calcium impairs thyroid hormone absorption; separate by ≥4 hours | |||
| Iron supplements — calcium inhibits non-haem iron absorption; separate administration | |||
This information is for educational purposes only and does not constitute medical advice. Always consult a qualified healthcare provider before using herbal medicines, especially if you take prescription medications.