The first symptoms of overdose will take place within 30 minutes of ingestion. Death will usually occur within 1 - 3 hours. Drowsi- ness and dizziness quickly progress to loss of consciousness, pos- sible seizures, arrhythmia and shock. Death follows from cardiac arrest.
Potentiating and Other Supplementary Drugs
Although the volume of this lethal drunk may be small, it is ex- tremely bitter and anti-emetics are essential. Metoclopramide 3x10mg taken 40 mins prior is suitable.
The use of benzodiazepines to mask the unpleasant symptoms associated with the cardiotoxic properties of the drug is recom- mended. A medium to fast-acting drug like oxazepam (eg Sere- pax 3 x 30mg) taken immediately after the chloroquine would be effective.
The reported protective effect of the benzodiazepine Valium (di- azepam), in particular, has been the subject of considerable de- bate. Medical journal articles describe the use of Valium in cases of severe overdose as a life-saving measure. For this reason, inter- current use of this drug should be avoided.
Specific potentiation can be achieved by taking the H2 antagonist cimetidine (eg. Tagamet 800mg taken as a pre-dose with the anti- emetic). Cimetidine interferes with chloroquine metabolism and pushes up serum levels.
Other drugs can also be usefully used to increase the lethal ef- fects of chloroquine. For example, alcohol, along with respiratory depressants (barbiturates) or cardiac inhibitors (B blockers) can serve this purpose.