Contraindications and precautions
The known contraindications of amitriptyline are:

Amitriptyline should be used with caution in patients with epilepsy, impaired liver function, pheochromocytoma, urinary retention, prostate enlargement, hyperthyroidism, and pyloric stenosis.In patients with the rare condition of shallow anterior chamber of eyeball and narrow anterior chamber angle, amitriptyline may provoke attacks of acute glaucoma due to dilation of the pupil. It may aggravate psychosis, if used for depression with schizophrenia, or precipitate the switch to mania in those with bipolar disorder.CYP2D6 poor metabolizers should avoid amitriptyline due to increased side effects. If it is necessary to use it, half dose is recommended. Amitriptyline can be used during pregnancy and lactation, in the cases when SSRI do not work. Side effects
The most frequent side effects, occurring in 20% or more of users, are dry mouth, drowsiness, dizziness, constipation, and weight gain (on average 1.8 kg). Other common side effects (in 10% or more) are vision problems (amblyopia, blurred vision), tachycardia, increased appetite, tremor, fatigue/asthenia/feeling slowed down, and dyspepsia.A literature review about abnormal movements and amitriptyline found that this drug is associated with various movement disorders, particularly dyskinesia, dystonia, and myoclonus. Stuttering and restless legs syndrome are some of the less common associations.A less common side effect of amitriptyline is urination problems (8.7%).Amitriptyline-associated sexual dysfunction (occurring at a frequency of 6.9%) seems to be mostly confined to males with depression and is expressed predominantly as erectile dysfunction and low libido disorder, with lesser frequency of ejaculatory and orgasmic problems.
There is no significant difference in the neonatal death rate in infants born to mothers with HG compared to infants born to mothers who do not have HG. Children born to mothers with undertreated HG have a fourfold increase in neurobehavioral diagnoses. Epidemiology
Vomiting is a common condition affecting about 50% of pregnant women, with another 25% having nausea. However, the incidence of HG is only 0.3–1.5%. After preterm labor, hyperemesis gravidarum is the second most common reason for hospital admission during the first half of pregnancy. Factors such as infection with Helicobacter pylori, a rise in thyroid hormone production, low age, low body mass index prior to pregnancy, multiple pregnancies, molar pregnancies, and a history of hyperemesis gravidarum have been associated with the development of HG. History
Thalidomide was prescribed for treatment of HG in Europe until it was recognized that thalidomide is teratogenic and is a cause of phocomelia in neonates. Etymology
Hyperemesis gravidarum is from the Greek hyper-, meaning excessive, and emesis, meaning vomiting, and the Latin gravidarum, the feminine genitive plural form of an adjective, here used as a noun, meaning "pregnant [woman]". Therefore, hyperemesis gravidarum means "excessive vomiting of pregnant women". Notable cases
Author Charlotte Brontë is often thought to have had hyperemesis gravidarum.