The short answer
If penicillamine is treating cystinuria, review methionine supplements before use. Methionine can contribute to cystine production; this concern is about the stone disorder, not a proven penicillamine blood-level interaction.
What this answer covers
L-methionine supplements during penicillamine treatment for cystinuria. An indication-related stone concern is distinct from a demonstrated drug absorption interaction.
- Supplement or preparation
- L-Methionine
- Medication ingredient
- penicillamine
Check the exact oral medicine
This applies to oral D-penicillamine capsules. The prescribed indication matters: Wilson’s disease, cystinuria and rheumatoid arthritis have different nutritional considerations. Penicillamine is not a penicillin antibiotic; other enantiomers are not treated as the same medicine.
The precaution follows the diagnosis
The penicillamine label describes limiting methionine as part of conventional cystinuria management. It also cautions that restrictive low-protein diets are unsuitable in growing children and pregnancy. This is not a diet instruction for every person taking penicillamine.
The published case used a mixture
A woman with cystinuria developed a large new stone after a hair supplement containing both cystine and methionine. No penicillamine co-use was reported. Her low urine volume and high sodium intake were additional concerns, and urinary cystine was not measured while she took the supplement. The case cannot isolate methionine’s effect or prove this exact drug interaction.
Discuss the product and nutrition plan
Bring hair, amino-acid and protein supplement labels to the stone-care team. They can decide whether to avoid the product while preserving adequate nutrition and the prescribed fluid plan. Separating methionine by a few hours is not a demonstrated way to prevent cystine production or stone risk.
Evidence and practical considerations
Timing & monitoring
A cystinuria-specific supplement precaution is supported; no exact penicillamine-methionine PK effect or protective spacing interval is established.
- Exact scope
- L-methionine supplements during penicillamine treatment for cystinuria. An indication-related stone concern is distinct from a demonstrated drug absorption interaction. with RxNorm7975 IN penicillamine. Clinical evidence concerns oral D-penicillamine, the enantiomer in the capsule label, not L-penicillamine or penicillin antibiotics.
- Medication form and route
- Oral
What remains uncertain
- Condition-specific label guidance plus uncontrolled mixed-supplement case without penicillamine exposure; no direct PK study or validated spacing. Dietary restrictions require age/pregnancy context.
Factors that may matter: Exact oral release formulation; Mineral salt and combination ingredients; Dosing order and meals; Treatment indication.
Read the supporting source summaries
Source 1: Current original prescribing information
dailymed.nlm.nih.gov · Source check Sep 10, 2026
Population: Patients prescribed the specified oral formulation.
Food, antacids and iron reduce absorption. General separation at least one hour; iron-specific two hours. Pyridoxine requirements increase; copper-free multivitamins in Wilson disease; cystinuria diet differs.
How this applies: RxNorm7975 IN penicillamine. Clinical evidence concerns oral D-penicillamine, the enantiomer in the capsule label, not L-penicillamine or penicillin antibiotics.
Exact indication, supplement composition and direction of effect matter. No universal mineral dose or two-hour rule.
Source 2: Original medication-use guidance
medlineplus.gov · Source check Sep 10, 2026
Population: Users of oral penicillamine.
Iron two hours apart; other medicines/antacids/zinc one hour apart. Empty stomach one hour before or two after meals. Pyridoxine and indication-specific dietary guidance.
How this applies: RxNorm7975 IN penicillamine. Clinical evidence concerns oral D-penicillamine, the enantiomer in the capsule label, not L-penicillamine or penicillin antibiotics.
Practical guidance, not a trial proving every listed interval restores exposure. Direction and formulation matter.
Source 3: Original clinical research
pubmed.ncbi.nlm.nih.gov · Source check Sep 10, 2026
Population: One 22-year-old woman with cystinuria.
A large new stone appeared after supplement use; authors considered the mixture a plausible contributor.
How this applies: Only stated preparation, route and endpoint; clinical outcome and PK are distinct.
Single uncontrolled case, mixed amino acids, pre-existing low urine volume/high sodium and no urinary cystine measurement during supplement use. No exact penicillamine PK interaction.
Source 4: Medication terminology
rxnav.nlm.nih.gov · Source check Sep 10, 2026
Population: Terminology.
penicillamine is IN.
How this applies: Exact ingredient.
Not clinical evidence.
Research assessment: · Open full citations ↗
Review and change history
- Publication status
- Published research summary
- Clinical review
- Not yet recorded
| Date | Update |
|---|---|
| Research summary published | |
| Article prepared | |
| Sources checked and article drafted. |
Article revision: 64e6be6550619a0c
This guide brings together the evidence records used by our interaction checker. Each finding retains its own preparation limits, research date, and source summaries.
Full citations require verification. Reading this answer and the source summaries does not.
Taking other supplements or medications?
Use the checker to explore your other combinations. Ask a pharmacist to review the exact products, amounts and medical conditions in your complete list.
Open the interaction checkerInformation, not medical advice. Do not change prescribed treatment based on this guide.