Other causes include:
Anxiety
Brain tumor
Chronic pains
Concussion – a mild traumatic brain injury
Diabetes
Fibromyalgia
Head injury
Hypercalcemia – too much calcium in the blood
Hypermagnesemia
Hyponatremia – low blood sodium
Hypothyroidism – the body doesnt produce enough hormones that control how cells use energy
Meningitis
Mood disorders – depression
Multiple sclerosis
Narcolepsy – disorder of the nervous system
Skull fractures
Sleeping sickness – caused by a specific parasite
Stress

Medicine
Analgesics – mostly prescribed or illicit opiates such as OxyContin or heroin
Anticonvulsants / antiepileptics – such as phenytoin (Dilantin), carbamazepine (Tegretol), Lyrica (Pregabalin) and Gabapentin
Antidepressants – for instance, sedating tricyclic antidepressants and mirtazapine. Somnolence is less common with SSRIs and SNRIs as well as MAOIs. Antihistamines – for instance, diphenhydramine (Benadryl, Nytol) and doxylamine (Unisom-2)
Antipsychotics – for example, Lurasidone (Latuda), thioridazine, quetiapine (Seroquel), olanzapine (Zyprexa), risperidone and ziprasidone (Geodon) but not haloperidol
Dopamine agonists used in the treatment of Parkinsons disease – e.g. pergolide, ropinirole and pramipexole. HIV medications – such as efavirenz
Hypertension medications – such as amlodipine
Hypnotics, or soporific drugs, commonly known as sleeping pills. Tranquilizers – such as zopiclone (Zimovane), or the benzodiazepines such as diazepam (Valium) or nitrazepam (Mogadon) and the barbiturates, such as amobarbital (Amytal) or secobarbital (Seconal)
Other agents impacting the central nervous system in sufficient or toxic doses

Assessment
Quantifying sleepiness requires a careful assessment. The diagnosis depends on two factors, namely chronicity and reversibility. Chronicity signifies that the patient, unlike healthy people, experiences persistent sleepiness, which does not pass. Reversibility stands for the fact that even if the individual goes to sleep, the sleepiness may not be completely gone after waking up.
Micturition syncope or post-micturition syncope is the name given to the human phenomenon of fainting shortly after or during urination. The underlying cause is not fully understood, but it may be a result of vasovagal response, postural hypotension, or a combination thereof. People often become pale, lightheaded, nauseated, sweaty and weak before they lose consciousness. Sometimes defecating, coughing, or severe vomiting may cause fainting in a similar way. Causes
When one strains to increase the flow of urine, it stimulates the vagus nerve (usually more pronounced in elderly men with large prostates). The vagus nerve stimulus causes slowing down of the heart (bradycardia) and a drop in blood pressure. The heart cannot perform effectively as a pump because insufficient blood comes to it. It can be associated with a very rare tumour known as a paraprostatic pheochromocytoma within the urinary bladder. Treatment
There is no specific treatment for micturition syncope. General advice to men with micturition syncope includes:
to sit while urinating
to sit on the edge of the bed for a while before getting up and going to the toilet
to avoid urinating while sleepy
to urinate before sleep
to stop urination, cross the legs, and flex them immediately upon feeling faintness

Epidemiology
Responsible for 2.4 to 8.4 percent of all cases of fainting in adults, it most commonly occurs in males. The events often occur at night or after awaking. References
External links
Micturition Syncope - Patient Plus