1. Management with Ethanol
METHANOL
POISONING
Management with Ethanol
IN NZ METHYLATED SPIRITS ONLY CONTAINS 5% METHANOL, THE REMAINING 95% IS ETHANOL - ANTIDOTAL TO THE METHANOL.
SOME COMMERCIAL FORMULATIONS OF METHANOL CAN BE UP TO 98%

2. MECHANISM OF ACTION METHANOL FORMALDEHYDE FORMIC ACID
ALCOHOL DEHYDROGENASE
ALDEHYDE DEHYDROGENASE
METHANOL
FORMALDEHYDE
FORMIC
ACID
METHANOL ITSELF NOT TOXIC. FORMALDEHYDE VERY TOXIC, BUT VERY RAPIDLY METABOLISED TO FORMIC ACID. FORMIC ACID RESPONSIBLE FOR THE TOXICITY RELATED TO METHANOL INGESTIONS

3. MECHANISM OF ACTION OCULAR TOXICITY CIRCULUS HYPOXICUS
METHANOL
OCULAR
TOXICITY
FORMALDEHYDE
INHIBITION OF MITOCHONDRIAL RESPIRATION
INCREASED FORMIC ACID TOXICITY
FORMIC
ACID
CIRCULATORY
FAILURE
CIRCULUS
HYPOXICUS
TISSUE
HYPOXIA
ACIDOSIS
ACIDOSIS
LACTIC ACID
PRODUCTION
Early stage
of poisoning
GENERAL TOXICITY

4. SIGNS AND SYMPTOMS INITIAL INEBRIATION - ESPECIALLY IF ETHANOL
COINGESTED
AFTER HOUR DELAY - PROGRESSION TO ACIDOSIS
AND OTHER SIGNS AND SYMPTOMS
MAY BE FURTHER DELAY WITH CONTINUED INGESTION
OF ETHANOL

5. SIGNS AND SYMPTOMS CNS - INEBRIATION PROGRESSING TO COMA, CONVULSIONS
RETINAL - BLURRED VISION, PHOTOPHOBIA, VISUAL
ACUITY LOSS, DILATED NON-REACTIVE PUPILS,
OPTIC NERVE HYPERAEMIC - BECOMING OEDEMATOUS
GIT - NAUSEA, VOMITING
CARDIAC - TACHYCARDIA, HYPERTENSION PROGRESSING
TO HYPOTENSION AND CARDIOGENIC SHOCK
RESPIRATORY - TACHYPNOEA

6. INVESTIGATION BLOOD METHANOL LEVEL! ABG - METABOLIC ACIDOSIS
OSMOLAL GAP - INCREASED (METHANOL)
ANION GAP - INCREASED (FORMIC ACID, LACTIC ACID)
BLOOD ETHANOL
MAGNESIUM, AMYLASE, POTASSIUM

7. TREATMENT HAZARD ASSESSMENT ABC’s TOXICOKINETICS ABSORPTION
DISTRIBUTION
METABOLISM
ELIMINATION
TOXICODYNAMICS
SUPPORTIVE CARE

8. TREATMENT CORRECTION OF METABOLIC ACIDOSIS
BICARBONATE (AGGRESSIVE TREATMENT)
CAN REVERSE VISUAL IMPAIRMENT
REDUCES MOVEMENT OF FORMATE TO THE CNS
MAY REQUIRE 400 TO 600 MMOL DURING FIRST FEW HOURS
REHYDRATION

9. MECHANISM OF ACTION METHANOL FORMALDEHYDE FORMIC ACID
ALCOHOL DEHYDROGENASE
ALDEHYDE DEHYDROGENASE
METHANOL
FORMALDEHYDE
FORMIC
ACID

10. MECHANISM OF ACTION X METHANOL ETHANOL ALDEHYDE ACETIC ACID
FORMALDEHYDE
FORMIC
ACID
ALCOHOL DEHYDROGENASE
ALDEHYDE DEHYDROGENASE
ETHANOL
ALDEHYDE
ACETIC
ACID

11. (REDUCES FORMATION OF TOXIC METABOLITES)
TREATMENT
ETHANOL
(REDUCES FORMATION OF TOXIC METABOLITES)
MAINTAIN BLOOD ETHANOL LEVEL OF mg/dl
LOADING DOSE
BEWARE OF EXISTING ETHANOL LEVEL
MAINTENANCE DOSE
TITRATED AGAINST RATE OF ELIMINATION
NON-ALCOHOLIC mg/dl/h
CHRONIC ALCOHOLIC mg/dl/h
CHILD 30 mg/dl/h

12. TREATMENT ETHANOL INDICATIONS BLOOD METHANOL LEVELS GREATER THAN
6.25 mmol/l (20 mg/dl)
IF HAEMODIALYSIS IS TO BE COMMENCED

13. TREATMENT ETHANOL HALF LIFE OF METHANOL IS USUALLY 15 - 30 HOURS
HALF LIFE OF METHANOL WITH ETHANOL TREATMENT
IS HOURS
YOU MAY THEREFORE HAVE A NON-SOBER PATIENT ON
THE WARD FOR SEVERAL (4 - 5) DAYS...

14. TREATMENT HAEMODIALYSIS METHANOL LOW MOLECULAR WEIGHT
NOT PROTEIN BOUND
LOW VOLUME OF DISTRIBUTION
THEREFORE IDEAL FOR HAEMODIALYSIS

15. TREATMENT HAEMODIALYSIS INDICATIONS ANY DEGREE OF VISUAL IMPAIRMENT
SEVERE METABOLIC ACIDOSIS
BLOOD METHANOL LEVEL GREATER THAN
15 mmol/l (50mg/dl)

16. METABOLISM METHANOL FORMALDEHYDE FORMIC ACID CO2 and H2O
ALCOHOL DEHYDROGENASE
ALDEHYDE DEHYDROGENASE
METHANOL
FORMALDEHYDE
FORMIC
ACID
FOLIC ACID
THF
MAGNESIUM
CO2 and H2O

17. TREATMENT FOLINIC ACID/FOLIC ACID
50 mg IV EVERY FOUR HOURS FOR 24 HOURS, OR WHILE
FORMIC ACID MAY STILL BE ACCUMULATING
MAGNESIUM
MgSO4 TITRATED AGAINST BLOOD MAGNESIUM LEVELS

18. METHYLATED SPIRITS METHYLATED SPIRITS IS 5% METHANOL, 95% ETHANOL
ACUTE INGESTION PRESENTS AS ETHANOL, RATHER THAN
METHANOL, POISONING
METHANOL INTOXICATION IS ONLY A CONCERN IF METHYLATED
SPIRSTS IS INGESTED CHRONICALLY

19. METHYLATED SPIRITS EXAMPLE IF 250 ml METHYLATED SPIRITS INGESTED:
BLOOD ETHANOL LEVEL = 450 mg/dl (LD50)
BLOOD METHANOL LEVEL = 24 mg/dl

20. METHYLATED SPIRITS EXAMPLE
IF 1.5 l METHYLATED SPIRITS INGESTED OVER SEVERAL
DAYS:
BLOOD ETHANOL LEVEL ~ 450 mg/dl (LD50)
BLOOD METHANOL LEVEL = 142 mg/dl
(IN 12 HOURS ETHANOL LEVEL = 100 mg/dl
METHANOL LEVEL = 124 mg/dl)