Head-to-head clinical analysis & difference comparison: details on mechanism of action, dosing, half-life, interactions, and maternal-fetal safety.
FASTIN vs DIPRIVAN
Clinician-reviewed, head-to-head comparison of mechanism, dosing, pharmacokinetics, and safety profiles.
Last clinically reviewed: July 2026 · OpiCalc Medical Review Team
Sympathomimetic amine that promotes release of norepinephrine and dopamine from presynaptic nerve terminals in the hypothalamus, suppressing appetite.
Propofol potentiates GABA-A receptor activity, leading to rapid sedation and hypnosis by enhancing chloride conductance and neuronal hyperpolarization.
Short-term adjunct in exogenous obesity,Off-label: Attention deficit hyperactivity disorder (ADHD)
Induction and maintenance of general anesthesia,Sedation for intubated, mechanically ventilated patients in intensive care units,Monitored anesthesia care (MAC) sedation,Treatment of refractory status epilepticus (off-label),Procedural sedation (off-label)
30 mg orally once daily in the morning, administered as a single dose.
Induction: 2-2.5 mg/kg IV bolus; maintenance: 25-75 mcg/kg/min IV infusion.
Terminal elimination half-life is approximately 16-20 hours for the immediate-release formulation. With sustained-release forms, effective half-life may extend to 24-34 hours due to prolonged absorption. Clinical context: time to reach steady state is about 3-5 days.
Terminal elimination half-life: 4-7 hours (with context of context-sensitive half-life increasing after prolonged infusion).
Hepatic metabolism via CYP3A4 and CYP2D6; active metabolite phendimetrazine (for some formulations).
Primarily hepatic conjugation to inactive metabolites (propofol glucuronide), with minor metabolism via CYP2B6 and CYP2C9 to 4-hydroxypropofol.
Primarily renal (approximately 70-80% unchanged) and biliary/fecal (20-30% as metabolites). Urinary excretion is p H-dependent; acidic urine increases elimination.
Renal (approximately 88% as metabolites, <1% unchanged); fecal (approximately 2%); other (10% as metabolites via other routes).
Approximately 40-50% bound to plasma proteins (albumin).
95-99% bound, primarily to albumin.
Approximately 3-5 L/kg. High Vd indicates extensive tissue distribution, including brain.
2-10 L/kg (large Vd indicating extensive tissue distribution).
Oral immediate-release: ~90% (high first-pass metabolism; absolute bioavailability is lower, but systemic exposure is adequate). Oral sustained-release: similar extent but with prolonged absorption.
Intravenous: 100%; not available orally due to extensive first-pass metabolism.
Contraindicated in severe renal impairment (e GFR <30 m L/min/1.73 m²). For moderate impairment (e GFR 30-59 m L/min/1.73 m²), reduce dose to 15 mg once daily.
No adjustment required; propofol is not significantly renally eliminated.
Contraindicated in Child-Pugh class C cirrhosis. In Child-Pugh class A or B, initiate at 15 mg once daily and titrate cautiously to maximum 30 mg once daily.
No specific Child-Pugh based guidelines; use lower doses due to impaired clearance, especially in cirrhosis.
Not recommended for pediatric patients under 16 years of age due to lack of safety and efficacy data.
Induction: 2.5-3.5 mg/kg IV bolus; maintenance: 125-300 mcg/kg/min IV infusion. Not approved for ICU sedation in <16 years.
Initiating at 15 mg once daily is recommended due to increased sensitivity and potential for central nervous system adverse effects; maximum dose 30 mg once daily.
Reduce induction dose to 1-1.5 mg/kg IV bolus and maintenance infusion to 20-50 mcg/kg/min IV due to increased sensitivity and decreased clearance.
None.
Propofol should be administered only by persons trained in the administration of general anesthesia and not involved in the conduct of the surgical/diagnostic procedure. Patients should be continuously monitored for early signs of hypotension, bradycardia, apnea, airway obstruction, and oxygen desaturation. For sedation of intubated, mechanically ventilated patients in the ICU, propofol should be used with caution in patients with increased intracranial pressure or impaired cerebral circulation.
Cardiovascular events (hypertension, tachycardia, stroke), psychiatric adverse effects (psychosis, dependence), primary pulmonary hypertension, valvular heart disease, tolerance, withdrawal symptoms, glaucoma, hyperthyroidism, seizure disorder, diabetes (dose adjustment required), elderly patients (higher sensitivity).
Risk of hypotension and bradycardia, especially in elderly or hypovolemic patients,Respiratory depression and apnea requiring airway management,Propofol infusion syndrome (PRIS): metabolic acidosis, rhabdomyolysis, renal failure, cardiac failure, especially with prolonged high-dose infusions,Hypertriglyceridemia; monitor lipids with prolonged use,Risk of pancreatitis,Use with caution in patients with epilepsy; may increase seizure risk during withdrawal,May cause green discoloration of urine, hair, or nails
Cardiovascular disease (e.g., coronary artery disease, arrhythmias, hypertension), hyperthyroidism, glaucoma, agitated states, history of drug abuse, MAOIs (concurrent or within 14 days), hypersensitivity to sympathomimetics.
Hypersensitivity to propofol or any component of the formulation,Hypersensitivity to eggs, egg products, soybeans, or soy products (due to lipid vehicle),Patients with severe lipid metabolism disorders (e.g., hyperlipidemia),Not recommended for general anesthesia in patients with increased intracranial pressure or impaired cerebral circulation unless benefits outweigh risks
Avoid excessive caffeine intake (e.g., coffee, tea, cola, energy drinks) as it may potentiate CNS and cardiovascular effects. Grapefruit juice may alter drug metabolism; avoid concurrent consumption. Maintain a balanced, reduced-calorie diet as part of the weight loss plan. Alcohol should be avoided due to potential additive CNS effects.
No specific food interactions; however, propofol emulsion contains soybean oil and egg lecithin, so avoid in patients with egg or soy allergies. The emulsion can be contaminated if bottle is reused; discard after single use. No dietary restrictions required for administration.
FDA Pregnancy Category X. First trimester: Increased risk of oral clefts and cardiac malformations with amphetamine use. Second and third trimesters: Risk of premature delivery, low birth weight, and neonatal withdrawal syndrome. Avoid use in pregnancy.
Propofol (DIPRIVAN) is Pregnancy Category B. Animal studies at clinical doses did not show teratogenicity. Use in first trimester only if clearly needed. During second and third trimesters, propofol crosses the placenta and may cause neonatal respiratory depression and neurobehavioral depression. Risk of fetal acidosis and bradycardia. No major teratogenic effects reported in human studies, but limited data.
Excreted in human milk; M/P ratio not established. Potential for adverse effects in nursing infants (irritability, poor feeding). Contraindicated during breastfeeding.
Propofol is excreted into breast milk in low concentrations. M/P ratio not established. Due to low oral bioavailability, risk to infant is minimal. However, caution is advised due to potential CNS depression in neonates. The manufacturer recommends discontinuing breastfeeding for 24 hours after administration.
Contraindicated in pregnancy; no dose adjustments recommended.
Pharmacokinetic changes in pregnancy include increased volume of distribution and clearance, particularly in the third trimester. No specific dose adjustment guidelines; clinical response and patient condition determine dosing. Reduced doses may be required due to increased sensitivity to propofol in pregnancy.
Fastin (phentermine) is a sympathomimetic amine indicated for short-term (up to 12 weeks) monotherapy for obesity. It should be used in conjunction with a reduced-calorie diet and exercise. Avoid co-administration with MAOIs or within 14 days of MAOI use due to hypertensive crisis risk. Use with caution in patients with hypertension, diabetes, or history of drug abuse. Monitor blood pressure and heart rate regularly. Tachyphylaxis may develop; discontinue if tolerance occurs. Do not use in patients with advanced arteriosclerosis, hyperthyroidism, glaucoma, or agitated states.
DIPRIVAN (propofol) causes pain on injection, especially in small veins; pretreatment with lidocaine or use of a larger vein can mitigate. It is formulated as a lipid emulsion containing soybean oil and egg lecithin, thus contraindicated in patients with egg or soybean allergies. Propofol can cause profound hypotension and respiratory depression; ensure airway equipment and vasopressors are immediately available. The infusion syndrome (PRIS) is rare but lethal, characterized by metabolic acidosis, rhabdomyolysis, and cardiac failure; avoid prolonged high-dose infusions (>5 mg/kg/hr for >48 hours).
Take Fastin exactly as prescribed, usually once daily in the morning to avoid insomnia.,Do not crush or chew the extended-release capsule; swallow whole.,Avoid taking late in the day to prevent difficulty sleeping.,Report any chest pain, palpitations, shortness of breath, or dizziness immediately.,Do not increase dose or take more frequently than prescribed; risk of dependence and side effects.,Fastin is for short-term use only (up to 12 weeks) and should be combined with a reduced-calorie diet and exercise.,Do not use if you have taken an MAO inhibitor in the last 14 days.,Avoid alcohol and other CNS stimulants (e.g., caffeine in large amounts) as they may increase side effects.,Do not stop abruptly; follow your doctor's instructions for tapering off.,Keep out of reach of children; misuse can cause severe cardiac toxicity.
You will be monitored continuously during and after administration due to risk of low blood pressure and slowed breathing.,You may feel a burning or stinging sensation at the injection site; inform your healthcare provider if it persists.,Do not drive or operate machinery for at least 24 hours after receiving propofol due to residual sedation.,Inform your medical team if you have allergies to eggs, soy, or sesame seeds.,Propofol is not intended for home use; it is only administered in a supervised medical setting.
No interactions on record
No interactions on record
Explore head-to-head clinical comparisons of other medications in the same therapeutic classes.
Common clinical questions about FASTIN vs DIPRIVAN, answered by our medical review team.
FASTIN is a Sympathomimetic Anorectic that works by Sympathomimetic amine that promotes release of norepinephrine and dopamine from presynaptic nerve terminals in the hypothalamus, suppressing appetite.. DIPRIVAN is a General Anesthetic that works by Propofol potentiates GABA-A receptor activity, leading to rapid sedation and hypnosis by enhancing chloride conductance and neuronal hyperpolarization.. They differ in pharmacokinetic profiles, FDA-approved indications, and side effect profiles.
Potency comparisons between FASTIN and DIPRIVAN depend on the specific clinical indication. These are agents from distinct pharmacological classes and are not directly interchangeable by dose. A physician or clinical pharmacist should guide any therapeutic switching decisions.
The standard adult dose of FASTIN is: 30 mg orally once daily in the morning, administered as a single dose.. The standard adult dose of DIPRIVAN is: Induction: 2-2.5 mg/kg IV bolus; maintenance: 25-75 mcg/kg/min IV infusion.. Dosing should always be individualized based on indication, renal and hepatic function, age, and other patient factors.
No direct drug-drug interaction has been formally documented between FASTIN and DIPRIVAN in current clinical databases. However, individual patient risk factors including other medications, organ function, and comorbidities should always be evaluated by a qualified healthcare provider.
The maternal-fetal safety profiles differ. FASTIN is classified as Category C. FDA Pregnancy Category X. First trimester: Increased risk of oral clefts and cardiac malformations with amphetamine use. Second and third trimesters: Risk of premature delivery, lo. DIPRIVAN is classified as Category C. Propofol (DIPRIVAN) is Pregnancy Category B. Animal studies at clinical doses did not show teratogenicity. Use in first trimester only if clearly needed. During second and third tr. Always consult a maternal-fetal medicine specialist before taking either drug during pregnancy or lactation.