Fenfluramine Effects

A distinct decrease in hunger and desire to eat, ranging from reduced interest in food to complete disinterest or even physical revulsion at the thought of eating. This effect can persist for many hours beyond the primary experience.

A diffuse, heavy physical discomfort involving tension, pressure, and malaise in the torso and limbs, commonly reported with tryptamines and phenethylamines.

Diarrhea is the occurrence of frequent, loose, or watery bowel movements as a side effect of certain psychoactive substances, resulting from either direct GI irritation or pharmacological alterations to gut motility and fluid absorption.

A sensation of spinning, swaying, or lightheadedness that impairs balance and spatial orientation, often accompanied by nausea and difficulty standing or walking steadily.

A persistent, uncomfortable reduction in saliva production causing the mouth and throat to feel parched, sticky, and difficult to swallow through, commonly known as cottonmouth.

Profuse perspiration exceeding normal thermoregulatory needs, common with stimulants and empathogens, contributing to dehydration risk.

Gait alteration is a noticeable change in the way a person walks and moves through their environment, often producing a robotic, mechanical, or shuffling movement pattern that is unusual in appearance but does not necessarily indicate loss of motor control.

A painful sensation of pressure, throbbing, or aching in the head that can range from a dull background discomfort to a debilitating pounding that dominates awareness. Substance-induced headaches may occur during the acute effects, during the comedown, or as a rebound symptom hours to days after use.

Increased blood pressure (hypertension) is an elevation of arterial pressure above the normal 120/80 mmHg baseline, commonly caused by stimulants, vasoconstrictors, and substances that activate the sympathetic nervous system, posing cardiovascular risks that increase with dose and pre-existing conditions.

A noticeable acceleration of heartbeat that can range from a subtle awareness of one's pulse to a forceful, rapid pounding felt throughout the chest, neck, and temples. This effect is among the most commonly reported physiological responses to psychoactive substances and often accompanies stimulation, anxiety, or physical exertion during intoxication.

Increased salivation (hypersalivation or sialorrhea) is the excessive production of saliva beyond what can be comfortably swallowed, commonly occurring with psychedelic tryptamines and certain antipsychotics as part of a broader parasympathetic activation pattern.

A persistent inability to fall asleep or maintain sleep despite physical tiredness, often characterized by a racing mind, heightened alertness, and a frustrating disconnect between bodily fatigue and mental wakefulness. This effect can persist for hours beyond the primary duration of a substance, significantly extending the total experience timeline.

A distinct decrease in the ability to control one's physical body with precision, balance, and coordination, ranging from minor clumsiness to complete inability to walk.

Muscle cramps are sudden, involuntary, and often painful contractions of muscles that occur as a side effect of certain psychoactive substances, particularly stimulating psychedelics and stimulants.

Persistent partial contractions or tightening of muscles that produces uncomfortable stiffness, cramping, and low-level aches throughout the body.

An uncomfortable sensation of queasiness and stomach discomfort that may or may not lead to vomiting, often occurring during the onset phase of many substances.

Physical fatigue is a state of bodily exhaustion characterized by reduced energy, diminished capacity for physical activity, and an overwhelming desire to rest, commonly experienced during comedowns or as a direct effect of sedating substances.

A state of deep physical and mental calming that manifests as a progressive desire to remain still, lie down, and eventually drift toward sleep. Sedation ranges from a gentle drowsy relaxation to a heavy, irresistible pull into unconsciousness where maintaining wakefulness becomes a losing battle against the body's insistence on shutdown.

Serotonin syndrome is a potentially fatal medical emergency caused by excessive serotonergic activity in the central and peripheral nervous systems, typically resulting from combining multiple serotonin-elevating substances, and manifesting as a dangerous triad of neuromuscular hyperactivity, autonomic dysfunction, and altered mental status.

An involuntary clenching and rhythmic grinding of the jaw muscles, known clinically as bruxism, that produces a compulsive need to clench, chew, or gnash the teeth together. This effect can range from a subtle tightness in the jaw to forceful, repetitive grinding that can cause significant dental damage and jaw pain during and after the experience.

Impaired thermoregulation causing unpredictable fluctuations between feeling hot and cold, with risk of hyperthermia or hypothermia.

Temporary erectile dysfunction is the substance-induced inability to achieve or sustain a penile erection sufficient for sexual activity, caused by vasoconstriction, sympathetic nervous system overactivation, or altered neurotransmitter signaling, and resolving once the drug's effects wear off.

A partial to complete suppression of anxiety and general unease, producing a calm, relaxed mental state free from worry. This can range from subtle tension relief to a profound sense of inner peace and emotional security.

A cognitive and emotional state of intense well-being, elation, happiness, and joy that manifests as a profound mental contentment and positive outlook. This ranges from gentle feelings of optimism and warmth to overwhelming bliss that pervades all thoughts and perceptions.

Mental exhaustion and difficulty sustaining thought after intense cognitive experiences, common during substance comedowns.

An impairment of abstract thinking marked by a persistent inability to grasp or comprehend concepts and situations that would normally be perfectly understandable during sobriety.

Reduced ability to evaluate risks, weigh options, and make sound judgments, particularly insidious because the individual often cannot recognize their own impairment.

A persistent state of low mood, emotional numbness, hopelessness, and diminished interest or pleasure in activities, often occurring during comedowns, withdrawal, or as a prolonged after-effect of substance use.

A perceptual disturbance in which the external world feels profoundly unreal, dreamlike, or artificially constructed, as though experienced through a veil, screen, or foggy barrier separating the observer from reality.

A marked reduction in social inhibitions, self-consciousness, and behavioral restraint that manifests as increased openness, talkativeness, and willingness to engage in activities one would normally avoid. Users often describe feeling as though an invisible social barrier has been lifted, allowing thoughts and impulses to flow directly into action without the usual filtering process.

A dramatic amplification of emotional responses in which feelings — whether positive or negative — become significantly stronger, more vivid, and more consuming than they would be in a sober state. The emotional landscape feels as though its contrast and saturation have been turned up, making joy more ecstatic, sadness more poignant, and love more overwhelming.

A blunting or flattening of emotional experience in which feelings become muted, distant, or seemingly absent. The individual may recognize intellectually that they should be feeling something in response to a situation — joy at good news, sadness at a loss, anxiety about a threat — yet the emotional charge simply is not there, as though an invisible pane of glass separates them from their own feelings.

Irritability is a sustained state of emotional reactivity in which the threshold for annoyance, frustration, and anger is significantly lowered — causing minor inconveniences, social interactions, or environmental stimuli that would normally be tolerated without difficulty to provoke disproportionate agitation or hostility.

A dose-dependent inhibition of one's ability to access and utilize short-term and long-term memory, ranging from mild forgetfulness to a profound inability to recall personal identity, biographical information, or the context of the current experience.

A panic attack is a discrete episode of acute, overwhelming fear or terror that arises suddenly and peaks within minutes, accompanied by distressing physical symptoms including rapid heartbeat, shortness of breath, chest tightness, trembling, dizziness, and a profound sense that one is dying, going insane, or losing control.

Irrational suspicion and belief that others are watching, plotting against, or intending harm toward oneself, ranging from mild unease to overwhelming terror.

A progressive onset of drowsiness, heaviness, and the desire to sleep that pulls the individual toward rest with increasing insistence. The eyelids feel weighted, the body sinks into whatever surface supports it, cognitive activity winds down into a pleasant fog, and the transition from waking consciousness toward sleep begins to feel not only appealing but inevitable.

The experience of thoughts occurring at a markedly reduced pace, as if the mind has been placed into slow motion. Internal dialogue becomes sparse and sluggish, with each idea taking longer to form and process, producing a sense of mental heaviness or cognitive inertia.

Subjective perception of time becomes dramatically altered — minutes may feel like hours, or hours pass in moments. Can manifest as either dilation or compression.