Safety

description Emergency Letter Template

Print this letter, fill in your details, and give a copy to your GP. Keep one on your phone, in your wallet, and at home.

event Editorial update September 2026

Use this as a starting point with your specialist, who should add your allergies, specific restrictions and emergency instructions. It cannot cover every situation. Keep a current copy and a wallet card. This template requires patient-specific completion by the treating team, including allergies, organ involvement, individual contraindications and emergency prescriptions. Carry a current copy and wallet summary. 1

MEDICAL ALERT - MITOCHONDRIAL DISEASE
m.3243A>G mutation in the MT-TL1 gene
Patient name:
Date of birth:
NHS / Hospital number:
Phenotype:
DRUG-SPECIFIC CONSIDERATIONS - COMPLETE WITH YOUR TEAM
Metformin Individual specialist decision; assess acid buildup risk and kidney/liver function. Individual risk–benefit review; assess lactic acidosis risk and renal/hepatic function. 12
Valproate / Valproic Acid Contraindicated in POLG disease. In non-POLG disease, consideration is limited to difficult-to-treat epilepsy or mood disorders without liver impairment; specialist and reproductive safety review are required. Contraindicated in POLG disease. In non-POLG disease without liver impairment, the 2024 consensus permits consideration for refractory epilepsy or refractory mood disorders, subject to other contraindications and reproductive safety requirements. 34
Aminoglycosides Check hearing, kidneys and genetic risk; m.3243A>G is not the MT-RNR1 risk genotype. Assess ototoxicity/nephrotoxicity and MT-RNR1-specific risk; do not infer that genotype from m.3243A>G. 15
Dichloroacetate (DCA) A MELAS trial stopped because of peripheral nerve toxicity. m.3243A>G MELAS trial terminated for peripheral neurotoxicity; no demonstrated clinical benefit. 6
Linezolid May be needed; review duration and monitoring for acid buildup. Individual indication/duration review and lactate monitoring as appropriate. 5
Chloramphenicol Route matters; eye treatment is not universally prohibited. Topical use is not universally contraindicated; assess systemic use separately. 5
OTHER MEDICINES TO REVIEW
Propofol (prolonged infusion) Brief anaesthesia and long infusions have different risks. Distinguish brief induction from prolonged infusion; individualise perioperative care. 15
Statins May be used with a review of muscle symptoms and appropriate monitoring. Assess cardiovascular benefit and muscle risk; monitor symptoms/CK as indicated. 5
SGLT2 inhibitors Review low-insulin and illness-related ketoacidosis risk. Assess insulin deficiency, reduced intake and intercurrent illness-related ketoacidosis risk. 27
Thiazolidinediones (TZDs) Review heart failure and fluid retention risk. Assess heart-failure and fluid-retention risk. 27
Nucleoside antivirals (e.g. AZT) Use an infection specialist’s drug-specific treatment plan. Drug-specific antiviral assessment of indication, organ function and interactions. 35
Tetracyclines Not universally prohibited; review the exact drug and reason for use. Not universally contraindicated; assess drug, indication and patient-specific risk. 5
EMERGENCY MANAGEMENT
  • Reduced intake or fasting: follow the specialist’s individual plan; assess the need for nutritional or glucose support. Catabolism: use individual fasting and nutritional support instructions, including indicated glucose management. 1
  • Fluids: choose type and amount using blood tests, fluid losses, diabetes, heart and kidney function. Fluids: individualise composition and rate to acid–base status, glycaemia, volume assessment and cardiac/renal function. 1
  • New neurological symptoms: assess urgently for stroke, seizures and a possible mitochondrial episode. Contact the specialist. Arginine benefit is unproven; this template does not prescribe it. Acute neurology: urgently assess vascular stroke, seizures and mitochondrial stroke-like episodes. Seek specialist advice; current evidence does not establish IV arginine efficacy. 18910
  • Monitoring: select blood sugar, lactate, acid balance, kidney and other checks according to the presentation. Monitoring: glucose, lactate, acid–base, renal and additional organ investigations as clinically indicated. 1
  • Infection or acute illness: assess promptly and treat the cause, with attention to intake and organ function. Intercurrent illness: promptly assess and treat the cause; monitor metabolic and organ status. 1
  • Procedures: involve the anaesthetist early and agree fasting, medicines, fluids and recovery monitoring. Perioperative care: individualise anaesthesia, fasting, metabolic support and postoperative monitoring. 15
CURRENT MEDICINES, ALLERGIES & INDIVIDUAL INSTRUCTIONS
Specialist name:
Specialist phone:
Hospital:
Specialist signature:
Date:
Further information: m3243ag.com/medications - Medication review guide
Patient-carried emergency aid. Not a substitute for clinician judgment or specialist advice.

References

10 sources

Sources for the information on this page.

  1. Sue CM, Balasubramaniam S, Bratkovic D, Bonifant C, Christodoulou J, Coman D, Crawley K, Edema-Hildebrand F, Ellaway C, Ghaoui R, Kava M, Kearns LS, Lee J, Liang C, Mackey DA, Murray S, Needham M, Rius R, Russell J, Smith NJC, Thyagarajan D, Wools C. (2022). Patient care standards for primary mitochondrial disease in Australia: an Australian adaptation of the Mitochondrial Medicine Society recommendations. Internal medicine journal. Clinical guidanceDOIFull text↑ Back to text
  2. Chaudhry A, Thompson DM, Chanoine JP. (2026). Diabetes management in maternally inherited diabetes and deafness (MIDD): A review and a proposed treatment algorithm. Diabetes, obesity & metabolism. ReviewDOIFull text↑ Back to text
  3. Mancuso M, Papadopoulou MT, Ng YS, Ardissone A, Bellusci M, Bertini E, Di Vito L, Evangelista T, Fons C, Hikmat O, Horvath R, Klopstock T, Kornblum C, Lamperti C, Licchetta L, Molnar MJ, Varhaug KN, O'Callaghan M, Pressler RM, Schiff M, Servidei S, Szabo N, Gorman GS, Cross JH, Rahman S. (2024). Management of seizures in patients with primary mitochondrial diseases: consensus statement from the InterERNs Mitochondrial Working Group. European journal of neurology. Clinical guidanceDOIFull text↑ Back to text
  4. Ratnaike TE, Elkhateeb N, Lochmüller A, Gilmartin C, Schon K, Horváth R, Chinnery PF. (2024). Evidence for sodium valproate toxicity in mitochondrial diseases: a systematic analysis. BMJ neurology open. Systematic reviewDOI↑ Back to text
  5. De Vries MC, Brown DA, Allen ME, Bindoff L, Gorman GS, Karaa A, Keshavan N, Lamperti C, McFarland R, Ng YS, O'Callaghan M, Pitceathly RDS, Rahman S, Russel FGM, Varhaug KN, Schirris TJJ, Mancuso M. (2020). Safety of drug use in patients with a primary mitochondrial disease: An international Delphi-based consensus. Journal of inherited metabolic disease. Clinical guidanceDOIFull text↑ Back to text
  6. Kaufmann P, Engelstad K, Wei Y, Jhung S, Sano MC, Shungu DC, Millar WS, Hong X, Gooch CL, Mao X, Pascual JM, Hirano M, Stacpoole PW, DiMauro S, De Vivo DC. (2006). Dichloroacetate causes toxic neuropathy in MELAS: a randomized, controlled clinical trial. Neurology. Randomised trialDOI↑ Back to text
  7. Chanoine JP, Thompson DM, Lehman A. (2025). Diabetes Associated With Maternally Inherited Diabetes and Deafness (MIDD): From Pathogenic Variant to Phenotype. Diabetes. ReviewDOIFull text↑ Back to text
  8. Mancuso M, Bellusci M, Carelli V, de Coo I, Diodato D, Distelmaier F, Hikmat O, Hirano M, Horvath R, Karaa A, Klopstock T, Koenig MK, Kornblum C, La Morgia C, Lopriore P, Martikainen MH, McFarland R, Musumeci O, Pitceathly RDS, Primiano G, Rahman S, Scaglia F, Schaefer A, Schiff M, Semmler L, Lamperti C, Servidei S. (2026). Diagnostic Criteria and Management of MELAS and Stroke-Like Episodes: Consensus-Based Statements. European journal of neurology. Clinical guidanceDOIFull text↑ Back to text
  9. Koga Y, Povalko N, Inoue E, Nakamura H, Ishii A, Suzuki Y, Yoneda M, Kanda F, Kubota M, Okada H, Fujii K. (2018). Therapeutic regimen of L-arginine for MELAS: 9-year, prospective, multicenter, clinical research. Journal of neurology. Clinical studyDOIFull text↑ Back to text
  10. Stefanetti RJ, Ng YS, Errington L, Blain AP, McFarland R, Gorman GS. (2022). l-Arginine in Mitochondrial Encephalopathy, Lactic Acidosis, and Stroke-like Episodes: A Systematic Review. Neurology. Systematic reviewDOIFull text↑ Back to text

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