Abstract
The largest known dose of mirtazapine taken alone is 1.5 g [1]. A 40 years old man presented to Modbury Hospital Accident and Emergency Department 16 hours after taking 1.8 g of mirtazapine, and 2 L of wine. He had a past history of cognitive impairment secondary to carbon monoxide poisoning and depression. He had slept for approximately 10 hours post-overdose.
Symptomatically he had some dizziness, nausea, a tremor, blurred vision and headache. On examination his temperature was 36.1, his pulse 108 and blood pressure 110/60. He had an intention tremor, and was dehydrated. His muscles were not tender. His chest had bibasal soft wheezes, and his liver was mildly tender and palpable.
There was evidence of slight bruising to the right eye.
On minimental examination he scored 29/30.
An electrocardiogram showed sinus tachycardia.
Complete blood examination: haemoglobin 14.7; white blood cell count 11.6 (with a neutrophilia); platelets were 240.
Liver function tests (LFT): albumin 45; alkaline phosphatase 81; bilirubin 4; GGT 102;, AST 92; ALT 56; LD 502.
Electrolytes were normal. The blood alcohol was zero, as were serum salicylate and paracetamol levels.
Cardiac enzymes: creatinine kinase (CK) 7578 (1% CK-MB). The CK peak was 9186 24 hours later.
Urinary myoglobin was positive at 288 μg (nr < 150).
Comparing the LFTs with previous results, the hepatitis was new, and his rhabdomyolysis resolved postintravenous fluids.
There were no complications and he was discharged from a medical ward 2 days post-admission.
There have been previous reports of rhabdomyolysis with mirtazapine, and it seems that the drug may have caused it in this overdose [2], [3].
A combination of mirtazapine and alcohol may have caused the hepatitis.
Again the above case shows that mirtazapine seems non-lethal in significant overdose [4].