What Factors Affect Phenylephrine Dosage?

Phenylephrine hydrochloride is used for the prevention and treatment of hypotension caused by spinal anesthesia, general anesthesia, application of chlorpromazine, etc. It is also used for supraventricular tachycardia and mydriasis.

Phenylephrine hydrochloride

Phenylephrine hydrochloride is used to prevent spinal anesthesia,

Phenylephrine hydrochloride

English name: Phenylephrine Hydrochloride

C9H13NO2.HCl 203.67

This product is (R)-(-)--[(

[Properties] This product is white or almost white crystalline powder; odorless, bitter.

This product is soluble in water or ethanol,

[Category]

1 Phenylephrine hydrochloride 1 dosage

: Subcutaneous or intramuscular injection, 2mg ~ 5mg / time for adults, 0.1mg / kg for children, can be repeated once after 1 ~ 2h. Intravenous drip, 5mg-20mg / time, drip rate does not exceed 180g / min, adjusted according to clinical response. Intravenous injection, 100 g ~ 5001 g / time, slowly injected at a concentration of 0.1%. Eye drops, 1 to 2 drops / time. Nose drops, 2 to 3 drops / time on each nostril, 4 times / day. Extremely, subcutaneous or intramuscular injection of 10 mg / time, intravenous infusion of 180 g / min.

[Drug overdose] Excessive increase in blood pressure, reflex bradycardia can be corrected with atropine, and other overdose can be treated with alpha blockers such as phentolamine.

Mortality has been reported with propranolol and hydrochlorothiazide. In patients with atropine, eye drops with this drug can cause boost and tachycardia.

(1) Alpha-blockers such as phentolamine, phenoxybenzamine, tolazoline, and phenothiazines can be used to reduce the pressure-increasing effect of this product.

(2) Used together with general anesthetics (especially cyclopropane or halogenated hydrocarbons), which may easily cause ventricular arrhythmia; it is also inappropriate to add this product to the local anesthesia solution for the tip of the toes to avoid extreme contraction of peripheral vessels , Causing tissue necrosis ulcers.

(3) With the use of antihypertensive drugs, the antihypertensive effect can be weakened.

(4) Used together with guanethidine, it can reduce the effect of guanethidine and make the boosting effect of this product synergistic.

(5) Used together with oxytocin, can cause severe hypertension.

(6) When used together with a monoamine oxidase (MAO) inhibitor, it can enhance the pressure-increasing effect of this product, and it should be disabled within 14 days after using the MAO inhibitor.

(7) With the sympathomimetic drugs, the potential adverse reactions of such drugs can be easily manifested.

(8) With the use of thyroid hormone, the effects of both are strengthened.

(9) With the same use of tricyclic antidepressants, the boosting effect of this product is enhanced.

(10) With the use of nitrates, the pressure-boosting effect of this product and the antianginal effect of nitrates can be reduced.

2 Phenylephrine hydrochloride 2 precautions:

It can cause high blood pressure with headache, vomiting, palpitations, bloated head, skin tingling and cold sensation, and mental symptoms such as hallucinations, delusions, mania can also occur. May cause irritation and discomfort at the site of administration. Leakage of intravenous injection can cause local tissue necrosis. Systemic reactions also occur after nasal and eye drops absorption.

Pregnancy category C, disabled during late pregnancy. Hyperthyroidism, hypertension, aortic aneurysm, arteriosclerosis, tachycardia or bradycardia, cardiomyopathy and other patients are forbidden, and elderly patients and diabetic patients should be used with caution. Eye drops are contraindicated in narrow-angle glaucoma and should not be used in infants. Patients receiving guanethidine and similar adrenergic nerve blockers are particularly sensitive to the pressure-boosting and dilated effects of this product. This product can reverse the antihypertensive effect of lisepine and methyldopa.

1. Cross-allergic reaction: those who are allergic to other sympathomimetic amines such as amphetamine, ephedrine, epinephrine, isoprenaline, norepinephrine, oxinalin, and metaisoproterenol may be abnormally sensitive to this product .

2. The following conditions should be used with caution: patients with severe atherosclerosis, bradycardia, hypertension, hyperthyroidism, diabetes, cardiomyopathy, cardiac block, ventricular tachycardia, peripheral or mesenteric artery thrombosis, etc.

3. In addition to measuring blood pressure frequently during treatment, other necessary inspections and monitoring should be performed according to different situations.

4. Prevent the medicinal solution from leaking out of the blood vessels and the occurrence of ischemic necrosis.

[Medication for pregnant women and lactating women] Animal tests have found fetal toxicity. Use in late pregnancy or during delivery can increase uterine contraction, reduce blood flow, and cause fetal hypoxia and bradycardia. Therefore, pregnant women should avoid using it when not necessary.

[Children's medicine] The application of this product in children has not been studied.

[Medication for elderly patients] The elderly should use it with caution, so as not to cause severe bradycardia or (and) decrease in cardiac output, which should be reduced appropriately.