Dose-dependence, homeostasis, "Start low, go slow." Delaying absorption.  Antidotes.

---

Summary:

1. Nausea is dose-dependent.

2. It is triggered by the rapid absorption of relatively large doses of medication at the onset of treatment, especially in patients who are treatment-naive (i.e, individuals who have never taken that medication before).

3. It is an early side effect that individuals rapidly develop tolerance to, and which does not tend to recur, particularly if dosage escalations are gradual and deferred.

4. Nausea can be mitigated by starting at low, often sub-therapeutic doses, which is always indicated when treating children, the elderly, low-weight individuals, individuals who metabolize medications slowly, and individuals prone to queasiness.  The low dosage should be increased slowly and very gradually, over days-to-weeks.

5.  Another early strategy is to divide the total daily dosage in two.  Taking the second dose even just a couple of hours later can dramatically reduce nausea.

6.  Because nutrients and medications are absorbed into the bloodstream from the small intestine, taking medication on a full stomach or with food (especially meals that contain fat, such as whole milk, which delay gastric emptying time) likewise slows absorption, mitigating queasiness.  For a few psychotropic medications, food actually facilitates absorption, such that those medicines must be taken with food--not to avoid nausea, but to be adequately absorbed into the bloodstream.

7. Slow- or extended-release preparations accomplish the same goal, allowing for the gradual absorption of medication over many hours.  There are many such technologies, which were developed for medications that otherwise have to be dosed multiple times a day.

8. Vomiting is an inherent, physiologic, cathartic reflex that is the culmination of intense queasiness, which is usually, but not always, immediately followed by relief from nausea.

9. The best antidotes for serotonin-induced nausea are prescription-only medications like Zofran (ondansetron) and Remeron (mirtazepine), 5-HT-3 serotonin receptor subtype antagonists, which block the nauseating effect of increased levels of serotonin by blocking serotonin from attaching to that receptor and triggering queasiness.  Zofran is not used by psychiatrists, because the aforementioned strategies are very effective at mitigating nausea caused by antidepressants, which is also short-lived, but Remeron is actually an antidepressant itself, which treats insomnia, stimulates the appetite, and can reverse the sexual dysfunction (anorgasmia) caused by other serotonergic antidepressants, and so it is often used.  Blocking the 5-HT-3 receptor reduces nausea due to other causes, as well.  Zofran is used to treat postoperative nausea due to the administration of general anesthetics and antibiotics during surgical procedures.

10. Opiates cause an ambulatory nausea that is best averted by keeping still and avoiding saccadic eye movements, such as reading.  It is a vestibular nausea akin to motion sickness (car-sickness and sea-sickness), triggered by signals to the brain from the inner-ear, in response to motion that is only problematic in certain contexts, including when opiate receptors are occupied by narcotic pain medications like hydrocodone, oxycodone, codeine, morphine, methadone and other opiates.  It can be alleviated in a few seconds by immediately lying down and closing one's eyes until the feeling passes.  The application of a cold compress to the face and neck area often helps to more quickly quell the urge to vomit.  The over-the-counter H-1 antihistamine Dramamine (dimenhydrinate) is recommended for motion sickness.  Phenergan (promethazine), a prescription medication which blocks dopamine receptors, but which also blocks histamine H-1 receptors, is useful for nausea induced by narcotic pain medications.  Both antihistaminergic medications are believed to reduce nausea by blocking the actions of acetylcholine, however.

11.  When it comes to the treatment of nausea, the old adage "An ounce of prevention is worth a pound of cure" is especially true.  Preventing nausea, when it is predictable, by taking an antiemetic prophylactically is vastly more effective than trying to alleviate the urge to vomit after-the-fact.

---

RETURN TO ARCHIVES