SER-AP-ES
Clinical safety rating
cautionComprehensive clinical and safety monograph for SER-AP-ES (SER-AP-ES).
SER-AP-ES is a combination product containing reserpine (depletes catecholamines from adrenergic nerve endings), hydralazine (direct vasodilation via smooth muscle relaxation), and hydrochlorothiazide (thiazide diuretic that inhibits sodium reabsorption in distal tubules).
| Metabolism | Reserpine: extensively metabolized in liver; Hydralazine: hepatic acetylation (N-acetyltransferase); Hydrochlorothiazide: not metabolized, excreted unchanged. |
| Excretion | Renal: 30-40% unchanged reserpine; 60-70% as metabolites (hydralazine: 50% renal, 15% fecal; hydrochlorothiazide: 95% renal unchanged). |
| Half-life | Reserpine: 50-100h (terminal); hydralazine: 2-8h (slow acetylators 4-8h, fast 2-4h); hydrochlorothiazide: 6-15h. Context: reserpine's long t½ accounts for prolonged effects; hydralazine requires dose adjustment for acetylator status. |
| Protein binding | Reserpine: 40% bound (albumin); hydralazine: 87% bound; hydrochlorothiazide: 40-68% bound (albumin). |
| Volume of Distribution | Reserpine: 6 L/kg; hydralazine: 1.6 L/kg; hydrochlorothiazide: 0.8 L/kg. Clinical meaning: reserpine extensive tissue distribution (fat, brain); hydralazine moderate; thiazide limited to extracellular fluid. |
| Bioavailability | Reserpine: 50% oral; hydralazine: 30-50% oral; hydrochlorothiazide: 65-75% oral. |
| Onset of Action | Oral: reserpine 3-6 days; hydralazine 20-30 min; hydrochlorothiazide 2h. |
| Duration of Action | Reserpine: 1-6 weeks (cumulative); hydralazine: 6-12h; hydrochlorothiazide: 12-16h. Note: reserpine's duration extends due to irreversible monoamine depletion. |
| Molecular Weight | Reserpine: 608.68 Da; Hydralazine: 236.27 Da; Hydrochlorothiazide: 297.74 Da (combination, average ~380 Da) |
SER-AP-ES is a combination antihypertensive tablet containing reserpine 0.1 mg, hydralazine hydrochloride 25 mg, and hydrochlorothiazide 15 mg. Usual adult dose: one tablet orally twice daily. Increase as needed to a maximum of two tablets twice daily.
| Dosage form | TABLET |
| Renal impairment | Hydrochlorothiazide: Contraindicated if CrCl < 30 mL/min. For CrCl 30-50 mL/min: reduce dose of hydrochlorothiazide to 12.5 mg daily; consider using individual components. Reserpine and hydralazine: no specific GFR-based adjustment, but use with caution if severe renal impairment. |
| Liver impairment | Reserpine and hydralazine are contraindicated in severe hepatic impairment. For Child-Pugh A or B: no specific dose adjustment but monitor closely. For Child-Pugh C: avoid use. |
| Pediatric use | Not recommended for pediatric use due to lack of safety and efficacy data. Use individual components with appropriate weight-based dosing if needed. |
| Geriatric use | Initiate with one tablet orally once daily. Titrate slowly due to increased risk of hypotension, electrolyte disturbances, and central nervous system effects. Monitor renal function and electrolytes closely. |
| 1st trimester | Contraindicated: Risk of fetal abnormalities including neural tube defects and cardiovascular malformations. |
| 2nd trimester | Contraindicated: Risk of fetal nephrotoxicity and oligohydramnios. |
| 3rd trimester | Contraindicated: Risk of neonatal hypotension, renal failure, and skull hypoplasia. |
Clinical note
Comprehensive clinical and safety monograph for SER-AP-ES (SER-AP-ES).
| Placental transfer | Extensive placental transfer; crosses readily. |
| Breastfeeding | Excreted in breast milk; may cause adverse effects in nursing infants. Use with caution; monitor infant for hypotension and electrolyte disturbances. |
| Lactation Rating | L4 - Possibly Hazardous |
| Teratogenic Risk | SER-AP-ES is a combination product containing reserpine, hydralazine, and hydrochlorothiazide. Reserpine: crosses placenta, animal studies show fetal abnormalities (skeletal and CNS) in high doses; first trimester risk uncertain, second/third trimester associated with neonatal respiratory depression, bradycardia, hypothermia. Hydralazine: animal studies show cleft palate, skeletal malformations; human data limited; risk not excluded. Hydrochlorothiazide: associated with neonatal thrombocytopenia, electrolyte disturbances, and possibly fetal or neonatal jaundice; second/third trimester use may cause fetal hypoxia and placental insufficiency. Overall, avoid in pregnancy unless benefit outweighs risk; first trimester highest risk. |
| Fetal Monitoring | Maternal: blood pressure, heart rate, electrolytes (especially potassium, sodium), renal function, signs of lupus-like syndrome or hepatotoxicity (hydralazine), depression (reserpine). Fetal/neonatal: growth ultrasound, fetal heart rate monitoring, assessment for thrombocytopenia and electrolyte disturbances (hydrochlorothiazide), and respiratory depression (reserpine). |
| Fertility Effects | Reserpine may impair fertility by altering hypothalamic-pituitary-gonadal axis, causing amenorrhea or gynecomastia. Hydralazine and hydrochlorothiazide have not been associated with significant fertility impairment. Overall, potential reversible decrease in fertility with reserpine component. |
■ FDA Black Box Warning
None
| Serious Effects |
Hypersensitivity to any componentActive peptic ulcerUlcerative colitisDepression (especially with suicidal risk)Severe renal impairment (anuria)Electrolyte imbalance (hypokalemia, hypercalcemia)Addison's disease
| Precautions | Reserpine: May cause depression, peptic ulcer activation., Hydralazine: Drug-induced lupus, peripheral neuritis (pyridoxine deficiency), tachycardia., Hydrochlorothiazide: Electrolyte imbalance, hyperuricemia, photosensitivity. |
| Food/Dietary | Avoid foods high in sodium to prevent bloating and counteract diuretic effect. Excessive potassium intake (e.g., salt substitutes, bananas, oranges) may be needed if hypokalemia is present, but monitor potassium levels. Grapefruit juice may alter absorption; avoid large amounts. Alcohol increases risk of hypotension and sedation; avoid concurrent use. |
| Clinical Pearls | SER-AP-ES is a combination antihypertensive containing reserpine, hydralazine, and hydrochlorothiazide. Reserpine depletes catecholamines centrally and peripherally; may cause depression, nasal congestion, and bradycardia. Hydralazine is a direct vasodilator; can cause drug-induced lupus-like syndrome, especially in slow acetylators. Hydrochlorothiazide is a thiazide diuretic; monitor for hypokalemia, hyponatremia, and hyperglycemia. Avoid use in patients with depression, peptic ulcer disease, or history of SLE. Titrate slowly due to reserpine's cumulative effect. |
| Patient Advice | Take exactly as prescribed; do not stop suddenly as this may cause rapid rise in blood pressure. · Avoid over-the-counter cold or allergy medications without consulting your doctor. · Report symptoms of depression, mood changes, or suicidal thoughts immediately. · May cause dizziness or drowsiness; avoid driving until you know how this medication affects you. · Do not consume alcohol; it may increase side effects. · Monitor your blood pressure regularly and keep a log. · Stay hydrated but avoid excessive salt intake. · Report any unexplained fever, joint pain, or skin rash; may be signs of lupus-like reaction. · This medication may increase blood sugar; monitor if diabetic. |
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