First Aid -- The following guidelines may be used (except where noted) by lay persons as a first aid treatment for acute cases of poisoning.  In any case of potential toxicity, the victim should be taken to an emergency room as quickly as possible.  These guidelines may be provided by the pharmacist to any person who may be on site at a poisoning case.  Generally, if the victim is unconscious or experiencing seizures, the best first aid is to call 911 and get professional medical help as quickly as possible.

Ingested Poisons --
1) Induce emesis with 15 ml (1 tablespoonful) of syrup of ipecacuanha, followed by ½ glass of water, to prevent absorption of the poison.  Ipecac should NOT be given to persons who have ingested corrosives such as acids or alkalies (further damaging mucosa during emesis) or petroleum distillates (increase risk of aspiration, causing pneumonia).

2) Induce catharsis with 1 bottle of citrate of magnesia or 2 tablespoonfuls of Fleets Phospho-Soda in ½ glass of water, to hasten elimination of any poison that may have passed from the stomach to the intestines.

3) Keep the patient warm and seek professional help.

Inhaled Poisons --
1) Remove from source and provide fresh air, loosen clothing if needed

2) Administer artificial respiration as required -- clear mouth and throat of vomitus or other matter that may block the air passages and follow general first aid procedures for resuscitation.

3) Keep the patient warm and seek professional help.

Topical Poisons --
1) Drench the skin with water in a tub or shower

2) If clothes are extensively contaminated -- have the victim disrobe under a stream of water or shower, to minimise additional exposure

3) Cleanse thoroughly with soap and water

4) Do NOT use chemical antidotes (i.e. acids for exposure to a base), since the resulting chemical reaction could cause additional harm

5) Seek professional help
 

Eye Poisons --
1) Hold the exposed eye(s) open and flush with running water for at least 15 min

2) Do NOT use chemical antidotes

3) Seek professional help

Snake Bite
1) Immobilise the patient and the bite area (apply a tourniquet, making sure that the pulse is not obliterated -- every 10 min, loosen the tourniquet for 1 min to prevent ischæmic damage) to limit the systemic spread of the venom

2) Transport (carefully) to a treatment centre as quickly as possible, to administer antivenin

3) Do NOT cut and suck the poison -- this does little good and potential harm

Subcutaneous Drug
1) Similar to Snake bites
 
For any chemical poisoning, the caregiver should also identify the potential toxicant
1) Physical State (gas, liquid, solid)
2) Odour
3) Trade Name
4) Use
5) Poison Label
6) Flammability
This information should be provided to the health professional as quickly as possible.

Gastric Lavage -- Introduction of a lavage tube into the stomach allows that organ to be flushed.  The stomach should be washed out 3-4 times with 300-400 ml of water for each washing.  Aliqouts of each wash should be saved for analysis to identify the poison and to determine the effectiveness of the lavage.  In cases of corrosive ingestion, special care should be taken with introduction of the lavage tube (especially if the ingestion occurred more the 30 min prior to lavage).  The smallest tube possible should be used and it should be slowly introduced into the stomach.  Additionally, lavage should NOT be performed with petroleum distillate poisoning, since aspiration may occur.

Activated Charcoal -- Should be administered orally (after lavage) or rectally to adsorb and prevent absorption of the poison.

Supportive Therapy -- The patient should always be provided therapy that is specific for the symptoms with which they present (fluids for shock, correction of metabolic acidosis or alkalosis, anticonvulsants for seizures, antiarrhythmics p.r.n., et c.).

Hasten the excretion of the toxicant -- This may be accomplished by several techniques.

Cathartics -- Magnesium citrate, as described previously

Forced Diuresis -- This may often occur anyway, if the patient is placed on fluids, to hasten the urinary excretion of absorbed drug

Peritoneal dialysis, Hæmodialysis -- filtration of the peritoneum (washing out or flushing the peritoneal cavity) or the blood will often remove the majority of a toxicant that is present in the circulation.

Charcoal Hæmoperfusion -- This relatively new technique is similar to hæmodialysis, except the blood is filtered through an activated charcoal column (replacing the dialysate bath) that adsorbs and traps the toxicant, allowing toxicant-free blood to be taken back to the patient.

In addition to the above treatments, antidotes may be useful to reverse the effects of some toxicant. In addition to the anti-venins, antidotes may be divided into four broad categories, based upon their action:
Pharmacological Antidotes -- These agents exert a pharmacologic action to either block the effects of the toxicant or cause a pharmacologic effect that is opposite that produced by the toxicant.  Examples of the former include naloxone (for opiates), flumazenil (for benzodiazepines), and pralidoxime for cholinesterase inhibitors.  Examples of the latter include atropine for cholinergics and the cholinergic agonists neostigmine or eserine for tricyclic antidepressants.

Antidotes that form complexes with the toxicant -- These agents include the chelators, which bind to and inhibit the toxic effect of metals or ions, such as digoxin immune fab fragments (Digibind® for digoxin) dimercaprol (for arsenic, mercury, gold), desferrioxamine (iron), calcium EDTA (lead), penicillamine (copper), Prussian blue (potassium ferrihexacyanoferrate for thallium), dicobalt EDTA (cyanide), and the combination of amyl nitrite, sodium nitrite and sodium thiosulphate (for nitroprusside toxicity or cyanide poisoning).

Pharmacology of Cyanide Poisoning Therapy -- as previously stated in the course, cyanide uncouples oxidative phosphorylation and may cause death within minutes to seconds  if sufficient cyanide is inhaled or absorbed (various forms of cyanide are used as fumigants and fertilizers and in rubber synthesis, chemical syntheses, and metal purification).  Signs and symptoms of cyanide toxicity include (but are not limited to) rapid respiration, severe hypotension, vomiting, convulsions, cyanosis, and coma.
 

Amyl nitrite -- causes the formation of  methæmoglobin which then complexes with the cyanide to form cyanomethæmoglobin

Sodium nitrite infusion -- continues this conversion to a greater extent

Sodiumthiosulphate -- converts the cyanide to thiocyanate, which is less toxic and may be more readily eliminated.

NOTE that over production of methæmoglobin may occur and cause life-threatening methæmoglobinæmia.  (Signs and symptoms methæmoglobinæmia may be confused with cyanide toxicity, since they include GI upset and cyanosis) of methylene blue should be available to correct this condition, should it occur.

Antidotes that decrease the formation of toxic metabolites -- Examples include N-acetyl cysteine for paracetamol and 4-methylpyrazole for ethylene glycol or methanol.

Physiologic Antidotes -- The administration of a non-drug compound which counteracts the toxicant action.  For example, the administration of oxygen for CO toxicity.

END COURSE MATERIAL