Their sweat glands may function abnormally or may not have developed at all because of inactive proteins in the sweat glands. Without normal sweat production, the body cannot regulate temperature properly. Therefore, overheating is a common problem, especially during hot weather. Access to cool environments is important. Salivary glands
Several studies have examined salivary flow rate in individuals and found parotid and submandibular salivary flow ranging from 5 to 15 times lower than average. This is consistent with the salivary glands being of ectodermal origin, although some findings have suggested that there is also mesodermal input. Teeth
The development of tooth buds frequently results in congenitally absent teeth (in many cases a lack of a permanent set) and/or in the growth of teeth that are peg-shaped or pointed. The enamel may also be defective. Cosmetic dental treatment is almost always necessary and children may need dentures as early as two years of age. Multiple denture replacements are often needed as the child grows, and dental implants may be an option in adolescence, once the jaw is fully grown. Nowadays the option of extracting the teeth and substituting them with dental implants is quite common. In other cases, teeth can be crowned. Orthodontic treatment also may be necessary. Because dental treatment is complex, a multi-disciplinary approach is best. Other features
People with ED often have certain cranial-facial features which can be distinctive: frontal bossing is common, longer or more pronounced chins are frequent, broader noses are also very common.
A study which compared 75 mg pethidine administered via intravenous injection (IV) and 100 mg administered orally (PO) to 10 mg oxycodone (IV) and 10 mg (PO), 10 mg morphine (IV) and 20 mg (PO), 2 mg hydromorphone (IV) and 4 mg (PO), and placebo (C) in the subjects self-reported subjective effects such as drug-liking (how many of the subjects enjoyed or not, the experience; if yes, what was the most enjoyable part and why?, etc.) and how eagerly did subject want to re-experience it, and after IV doses were administered, pethidine 75 mg second-highest rates of drug-liking, after morphine 10 mg. Descriptive adjectives for morphine by subjects were:  “more sedating”, “more relaxing” and in comparison to the others, many subjects described that the experience was “more intense”. Pethidine followed, then hydromorphone, oxycodone and last was placebo. Upon oral administration, preference went from (greatest>least): oxycodone 10 mg>morphine 20 mg>hydromorphone 4 mg>pethidine 100 mg>placebo. The especially severe side effects unique to pethidine among opioids—serotonin syndrome, seizures, delirium, dysphoria, tremor—are primarily or entirely due to the action of its metabolite, norpethidine. Pharmacokinetics
Pethidine is quickly hydrolysed in the liver to pethidinic acid and is also demethylated to norpethidine, which has half the analgesic activity of pethidine but a longer elimination half-life (8–12 hours); accumulating with regular administration, or in kidney failure. Norpethidine is toxic and has convulsant and hallucinogenic effects.