Nausea and Other Physical Effects

Overview

Alongside changes in mind and perception, these substances also act on the body. The most commonly reported effects in the sources below are nausea, vomiting, headache, dizziness, and rises in blood pressure and heart rate. This page lists what was reported. It is not advice on using anything, and the body effects of one substance cannot be assumed for another.

Evidence labels used here: approved medicine (regulator and indication named), established (measured repeatedly in controlled studies), insufficient evidence and evidence of harm.

Across psychedelic and dissociative drugs

NIDA says physical side effects such as headache, nausea or changes in heart rate are generally not life-threatening. It also warns that illicitly made drugs may be contaminated with colorless, odorless fentanyl or other dangerous substances that can cause serious adverse events, including overdose and death. [1] For psilocybin, NIDA says the substance typically raises blood pressure and heart rate, which may be dangerous for people with heart conditions, and that people may have agitation, confusion, vomiting or nausea that can be severe and require medical attention. [2] It adds that exposures reported to poison control centers have increased, and that misidentifying a mushroom is a risk. [2] See poisoning and misidentification.

Psilocybin in controlled studies

• Blood pressure and hormones. In eight healthy volunteers given increasing amounts, mean arterial blood pressure was moderately raised only about 60 minutes after the highest amount, while ECG and body temperature were unaffected at every amount. Some hormones, including cortisol, were raised at peak effect. [3]
• Headache. In 18 healthy volunteers across a range of amounts, psilocybin frequently caused headache, with incidence, duration and severity rising with amount. All headaches began late, were transient and lasted no more than a day, and were neither severe nor disabling. [4]
• In a depression trial. In a phase 2 trial in treatment-resistant depression, 77% of participants had adverse events, including headache, nausea and dizziness. [5]
• Compared with LSD. In 28 healthy participants, psilocybin raised blood pressure more than LSD and LSD raised heart rate more than psilocybin, while both had comparable effects on the heart's workload (rate-pressure product). [6] This does not establish a dose equivalence between the two and we do not give one.

LSD

In 16 healthy volunteers, LSD moderately increased blood pressure and heart rate in a dose-related study. [7] Label: established for screened healthy volunteers in research settings.

DMT and ayahuasca (two different things)

• Intravenous DMT (a research route) dose-dependently raised blood pressure, heart rate, pupil size and body temperature in 11 experienced users. [8]
• Ayahuasca is a traditional plant-based brew containing DMT and other compounds. In a trial of freeze-dried ayahuasca in 18 volunteers, diastolic blood pressure rose at the higher amount (9 mm Hg at 75 minutes), while systolic pressure and heart rate rose moderately and not significantly. [9] The sources we read for this page did not report how often vomiting occurs with ayahuasca, so proper evidence not found here on that point. See ayahuasca.

MDMA and ketamine

• MDMA. NIDA lists higher blood pressure, involuntary jaw clenching, nausea, vomiting and restless legs. It also describes a dangerous steep rise in body temperature (hyperpyrexia), particularly with strenuous activity or a warm environment. [10] Label: evidence of harm for non-clinical use.
• Ketamine. NIDA lists headache, dizziness, sleepiness, blurred vision and nausea, with changes in blood pressure and heart rate. [11]

Esketamine (FDA label)

Label: approved medicine (FDA; treatment-resistant depression, and depressive symptoms in major depressive disorder with acute suicidal ideation or behavior). [12]

• It causes increases in blood pressure at all recommended amounts; increases peak about 40 minutes after use and last about 4 hours. [12]
• Blood pressure is checked before and after each dose, and the label says not to give it if a rise in blood pressure or pressure in the skull poses a serious risk. [12]
• Nausea and vomiting can occur; most events resolved the same day, with median duration not exceeding 1 hour in most patients, and they became less frequent over time. [12]

Special groups

Because these substances raise blood pressure and heart rate, people with heart or blood-vessel conditions are a group the sources flag for concern. [2][12] See cardiovascular risks and psychedelic adverse effects and contraindications. Anyone taking prescription medicines should speak with their prescriber; this page does not advise starting or stopping any medicine.