Head-to-head clinical analysis & difference comparison: details on mechanism of action, dosing, half-life, interactions, and maternal-fetal safety.
ACTAHIST vs SUPRENZA
Clinician-reviewed, head-to-head comparison of mechanism, dosing, pharmacokinetics, and safety profiles.
Last clinically reviewed: July 2026 · OpiCalc Medical Review Team
Antihistamine; binds to histamine H1 receptors, blocking the effects of histamine; also exhibits anticholinergic and mild sedative properties.
Partial agonist at mu-opioid receptors; also a weak antagonist at kappa-opioid receptors. Provides analgesic effects with reduced respiratory depression compared to full agonists.
Symptomatic relief of allergic rhinitis,Urticaria,Off-label: motion sickness,Off-label: insomnia
Management of moderate to severe chronic pain,Off-label: Treatment of opioid use disorder (as a maintenance therapy similar to buprenorphine)
1.34 mg (one capsule) orally twice daily.
Adults: 200 mg orally twice daily with meals.
6.9 ± 1.7 hours in adults; prolonged to 12-18 hours in elderly or patients with hepatic impairment, requiring dosing interval adjustment.
Terminal elimination half-life is approximately 12-15 hours in patients with normal renal function, allowing for twice-daily dosing.
Hepatic metabolism via CYP450 enzymes (primarily CYP3A4 and CYP2D6); major metabolite is inactive.
Primarily hepatic via CYP3A4 and CYP3A5 to norbuprenorphine (active metabolite); also undergoes glucuronidation.
Primarily renal (approximately 85% as unchanged drug and metabolites) and fecal (15%) via biliary elimination.
Approximately 60-80% of a dose is excreted renally as unchanged drug, with 20-40% eliminated via biliary/fecal routes.
92% bound to albumin.
Approximately 95-98% bound to plasma proteins, primarily albumin.
0.9 ± 0.3 L/kg, indicating extensive extravascular distribution.
Volume of distribution is approximately 2-3 L/kg, indicating extensive tissue distribution beyond plasma volume.
Oral: 68% ± 12% due to first-pass metabolism.
Oral bioavailability is approximately 70-80%.
No dose adjustment required for mild to moderate renal impairment. Safety not established for severe impairment (GFR <30 m L/min).
e GFR <45 m L/min/1.73m²: contraindicated. e GFR ≥45: no adjustment.
No dose adjustment required for mild to moderate hepatic impairment (Child-Pugh A or B). Not recommended for severe hepatic impairment (Child-Pugh C).
Child-Pugh Class A: no adjustment; Class B: reduce to 200 mg once daily; Class C: contraindicated.
Not indicated for pediatric patients under 12 years of age. Safety and efficacy not established.
Not recommended for patients under 18 years; safety and efficacy not established.
No specific dose adjustment recommended; monitor for increased anticholinergic effects and cognitive impairment.
No specific dose adjustment; monitor renal function and use caution due to increased risk of adverse effects.
None.
Risk of respiratory depression, especially in non-opioid-tolerant patients. Risk of neonatal opioid withdrawal syndrome with prolonged use during pregnancy. Risk of serious injury or death due to accidental exposure in children.
May cause drowsiness; caution when driving or operating machinery. Avoid alcohol. Use with caution in patients with narrow-angle glaucoma, prostatic hyperplasia, or urinary retention. Geriatric patients more sensitive to anticholinergic effects. Pediatric patients <6 years: not recommended.
Respiratory depression, particularly in the first 24-72 hours of treatment; caution in patients with pulmonary disease. Risk of QT prolongation. Adrenal insufficiency. Severe hypotension. Risk of misuse, abuse, and addiction. Tolerance and physical dependence.
Hypersensitivity to any component. Newborns or premature infants. Breastfeeding (contraindicated due to risk of adverse effects in infants). Concomitant use with MAOIs.
Hypersensitivity to buprenorphine or any component of the formulation. Severe respiratory insufficiency. Acute or severe bronchial asthma. Gastrointestinal obstruction, including paralytic ileus.
Avoid high-tyramine foods (aged cheese, cured meats, fermented products) if taking MAOIs. Grapefruit juice may increase phenylephrine absorption; limit intake.
No significant food interactions. Grapefruit juice may increase buprenorphine levels; avoid large quantities.
ACTAHIST (brompheniramine/phenylephrine) pregnancy category C. Inadequate human data; animal studies show no malformations at therapeutic doses. First trimester: theoretical risk from vasoconstrictive effects (phenylephrine) possibly reducing uterine blood flow; avoid if possible. Second/third trimester: phenylephrine may cause fetal hypoxia via placental vasoconstriction; use only if benefit outweighs risk. No known structural teratogenicity.
Supr ENza (testosterone) is contraindicated in pregnancy due to virilization of female fetus. First trimester: high risk of clitoromegaly, labial fusion, and urogenital sinus abnormalities. Second and third trimesters: risk of continued virilization, including phallic enlargement and ambiguous genitalia. Fetal growth restriction may occur.
Brompheniramine is excreted in breast milk in small amounts; M/P ratio not established. Phenylephrine has minimal excretion. Due to anticholinergic effects, may reduce milk production or cause sedation in infants. Use caution; prefer non-sedating alternatives if possible.
Testosterone is present in breast milk; M/P ratio not reported. Avoid breastfeeding due to potential for androgenization of the infant. Use only if clearly needed and no safer alternative.
No specific pharmacokinetic studies. Increased plasma volume and renal clearance in pregnancy may reduce drug levels, but efficacy threshold remains. No dose adjustment recommended; use the lowest effective dose for shortest duration due to potential risks.
Not applicable; Supr ENza is contraindicated in pregnancy. No dose adjustments are recommended as use is avoided entirely.
Actahist is a combination antihistamine-decongestant (chlorpheniramine/phenylephrine). Avoid in patients with hypertension, severe coronary artery disease, or MAOI use. Monitor for sedation and urinary retention, especially in elderly males with BPH.
SUPRENZA (buprenorphine/naloxone) sublingual film is used for opioid dependence. Monitor for respiratory depression especially when combined with benzodiazepines or alcohol. The naloxone component is poorly absorbed sublingually but precipitates withdrawal if injected. Administer only after clear signs of withdrawal to avoid precipitated withdrawal. Adjust dose in hepatic impairment as buprenorphine is hepatically metabolized.
Take with food or milk to reduce stomach upset.,Avoid alcohol and CNS depressants as they can increase drowsiness.,Do not drive or operate machinery until you know how this medication affects you.,Contact your doctor if you experience chest pain, rapid heartbeat, or difficulty urinating.
Take exactly as prescribed; do not increase dose or frequency without consulting your doctor.,Place film under the tongue until fully dissolved; do not chew or swallow.,Avoid alcohol and benzodiazepines as they can cause severe respiratory depression.,Keep out of reach of children; accidental exposure can be fatal.,Do not abruptly stop; withdrawal symptoms may occur.,Store at room temperature away from moisture and heat.
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 ACTAHIST vs SUPRENZA, answered by our medical review team.
ACTAHIST is a Antihistamine that works by Antihistamine; binds to histamine H1 receptors, blocking the effects of histamine; also exhibits anticholinergic and mild sedative properties.. SUPRENZA is a Sympathomimetic Anorectic that works by Partial agonist at mu-opioid receptors; also a weak antagonist at kappa-opioid receptors. Provides analgesic effects with reduced respiratory depression compared to full agonists.. They differ in pharmacokinetic profiles, FDA-approved indications, and side effect profiles.
Potency comparisons between ACTAHIST and SUPRENZA 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 ACTAHIST is: 1.34 mg (one capsule) orally twice daily.. The standard adult dose of SUPRENZA is: Adults: 200 mg orally twice daily with meals.. 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 ACTAHIST and SUPRENZA 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. ACTAHIST is classified as Category C. ACTAHIST (brompheniramine/phenylephrine) pregnancy category C. Inadequate human data; animal studies show no malformations at therapeutic doses. First trimester: theoretical risk f. SUPRENZA is classified as Category C. SuprENza (testosterone) is contraindicated in pregnancy due to virilization of female fetus. First trimester: high risk of clitoromegaly, labial fusion, and urogenital sinus abnorm. Always consult a maternal-fetal medicine specialist before taking either drug during pregnancy or lactation.