Overdose : מינון יתר

4.9 Overdose
An overdose of Mestinon dragees 60 mg can lead to a cholinergic crisis which necessitates intensive care monitoring. If a situation like this is not recognised, there is a risk of life- threatening respiratory muscle paralysis.

Possible symptoms of a cholinergic crisis
Muscarinic effects
Hypersalivation, lacrimation, rhinorrhoea, light to heavy sweating, increased bronchial secretion, bronchospasm, skin redness, miosis and accommodation disorders, dizziness, nausea, vomiting, increased peristalsis and diarrhoea, involuntary micturition and defecation with abdominal cramps, extreme bradycardia to the point of cardiac arrest, a drop in blood pressure through to circulatory collapse, periodic sinus tachycardia, pulmonary oedema.

Nicotinergic effects
Occasional muscle cramps, fasciculations, adynamia, general weakness through to paralysis which can lead to apnoea and cerebral anoxia in particularly serious cases.
Symptoms involving the central nervous system can be observed, including unrest, confusion, slurred speech, nervousness, irritability, and visual hallucinations.
Convulsions and coma may occur.

Treatment of a cholinergic crisis
- Immediately discontinue acetylcholinesterase inhibitors. Stop medications for 3 to 4 days - Artificial respiration in the event of significant respiratory depression - Slow intravenous administration of atropine (1 to 2 mg atropine sulphate) (every 5 to 30 min. if necessary) and dose reduction according to clinical factors (particularly pulse rate) - No plasma therapy
- In the case of heavy congestion: intensive respiratory toilet, i.v. fluids, secretolytics, broncholytics if necessary.
- Careful resumption of acetylcholinesterase inhibitor therapy, e.g. start with 0.5 mg pyridostigmine bromide parenterally every 4 to 6 hours or 4 x 20 mg pyridostigmine bromide orally

Treatment in the case of accommodation disorders Mydriatics, e.g. tropicamide (monitor pressure!).