NEFRISOL Phenylephrine HCl Injection B.P. / USP

10 mg/ml


For the use of a Registered Medical Practitioner or a Hospital or a Institution only. 

Maintains Adequate Level of Blood Pressure during Spinal and Inhalation Anaesthesia
Prolongs Spinal Anaesthesia
Useful in Drug Induced Hypotension & Vascular Failure in Shock

NEFRISOL-P (Phenylephrine hydrochloride) is a vasoconstrictor and pressor drug chemically related to adrenaline and ephedrine. Chemically, Phenylephrine hydrochloride is designated as Benzenemethanol,3-hydroxy-α-[(methylamino)methyl]-,hydrochloride(R)-.(-)-m-Hydroxy-α-[(methylamino)methyl]benzyl alcohol hydrochloride. Its molecular formula is C9H13NO2·HCl and its molecular weight is 203.70.   

Its structural formula is :

Phenylephrine HCl Injection


NEFRISOL-P is a clear, colourless sterile solution filled in 1 ml amber glass ampoule.

Each ml contains :
Phenylephrine Hydrochloride I.P. 10 mg
Water for Injections I.P.                     q.s.
Contains no preservatives.

Phenylephrine hydrochloride produces vasoconstriction that lasts longer than that of adrenaline and ephedrine. Responses are more sustained than those to adrenaline, lasting 20 minutes after intravenous and as long as 50 minutes after subcutaneous injection. Its action on the heart contrasts sharply with that of adrenaline and ephedrine, in that it slows the heart rate and increases the stroke output producing no disturbance in the rhythm of the pulse. Phenylephrine hydrochloride is a powerful postsynaptic alpha-receptor stimulant with little effect on the beta-receptors of the heart. In therapeutic doses, it produces little if any stimulation of either the spinal cord or cerebrum. A singular advantage of this drug is the fact that repeated injections produce comparable effects.

The predominant actions of Phenylephrine hydrochloride are on the cardiovascular system. Parenteral administration causes a rise in systolic and diastolic pressures in man and other species. Accompanying the pressor response to Phenylephrine hydrochloride is a marked reflex bradycardia that can be blocked by atropine; after atropine, large doses of Phenylephrine hydrochloride increase the heart rate only slightly. In man, cardiac output is slightly decreased and peripheral resistance is considerably increased. Circulation time is slightly prolonged and venous pressure is slightly increased; venous constriction is not marked. Most vascular beds are constricted; renal splanchnic, cutaneous and limb blood flows are reduced but coronary blood flow is increased. Pulmonary vessels are constricted and pulmonary arterial pressure is raised. The drug is a powerful vasoconstrictor, with properties very similar to those of norepinephrine but almost completely lacking the chronotropic and inotropic actions on the heart. Cardiac irregularities are seen only very rarely even with large doses.

NEFRISOL-P is intended for the maintenance of an adequate level of blood pressure during spinal and inhalation anaesthesia and for the treatment of vascular failure in shock, shock-like states and drug induced hypotension or hypersensitivity. It is also employed to overcome paroxysmal supraventricular tachycardia, to prolong spinal anaesthesia and as a vasoconstrictor in regional analgesia.


Administration :
NEFRISOL-P is generally injected subcutaneously, intramuscularly, slowly intravenously or in dilute solution as a continuous intravenous infusion. In patients with paroxysmal supraventricular tachycardia and if indicated, in case of emergency, NEFRISOL-P is administered directly intravenously.

The ampoule used in this product is equipped with O.P.C. (One Point Cut) opening system. No ampoule file is needed to open the ampoule. The neck of the ampoule is prescored at the point of constriction. A coloured dot on the ampoule head helps to orientate the ampoule. Take the ampoule and face the coloured dot. Let the solution at the head of the ampoule to flow down by shaking or a gentle stroke. The ampoule opens easily by placing the thumb on the coloured dot and gently pressing downwards as shown.

Ampoules equipped with One Point Cut (OPC) technology

Dosage :
The dose should be adjusted according to the pressor response.
Dosage calculations are shown in Table 1.

Table 1 – NEFRISOL- P Dosage and Administration

Phenylephrine HCl Injection
For convenience in intermittent intravenous administration, dilute 1 ml NEFRISOL-P 1 % with 9 ml Sterile Water for Injection I.P., to yield 0.1 % NEFRISOL-P.
Table 2 - NEFRISOL-P Dosage and Administration
Phenylephrine HCl Injection


Mild or Moderate Hypotension :
Subcutaneously or Intramuscularly :
Usual dose, from 2 mg to 5 mg. Range, from 1 mg to 10 mg. Initial dose should not exceed  5 mg.
Intravenously :
Usual dose, 0.2 mg. Range, from 0.1 mg to 0.5 mg. Initial dose should not exceed 0.5 mg. Injections should not be repeated more often than every 10 to 15 minutes. A 5 mg intramuscular dose should raise blood pressure for 1 to 2 hours. A 0.5 mg intravenous dose should elevate the pressure for about 15 minutes.
Severe Hypotension and Shock-Including Drug-Related Hypotension :
Blood volume depletion should always be corrected as fully as possible before any vasopressor is administered. When, as an emergency measure, intra-aortic pressures must be maintained to prevent cerebral or coronary artery ischemia, Phenylephrine hydrochloride can be administered before and concurrently with blood volume replacement. Hypotension and occasionally severe shock may result from overdosage or idiosyncrasy following the administration of certain drugs, especially adrenergic and ganglion blocking agents, rauwolfia and veratrum alkaloids and phenothiazine tranquilizers. Patients who receive a phenothiazine derivative as preoperative medication are especially susceptible to these reactions. As an adjunct in the management of such episodes, Phenylephrine hydrochloride is a suitable agent for restoring blood pressure. Higher initial and maintenance doses of Phenylephrine hydrochloride are required in patients with persistent or untreated severe hypotension or shock. Hypotension produced by powerful peripheral adrenergic blocking agents, chlorpromazine or pheochromocytomectomy may also require more intensive therapy. 
Continuous Infusion : 
Add 10 mg of the drug ( 1 ml of 1 % solution) to 500 ml of Dextrose 5 % Injection I.P. or Sodium Chloride 0.9 % Injection I.P. (providing a 1 : 50,000 solution). To raise the blood pressure rapidly, start the infusion at about 100 mcg to 180 mcg per minute (based on 20 drops per ml this would be 100 to 180 drops per minute). When the blood pressure is stabilized (at a low normal level for the individual), a maintenance rate of 40 mcg to 60 mcg per minute usually suffices (based on 20 drops per ml this would be 40 to 60 drops per minute). If the drop size of the infusion system varies from the 20 drops per ml, the dose must be adjusted accordingly. If a prompt initial pressor response is not obtained, additional increments of Phenylephrine hydrochloride (10 mg or more) are added to the infusion bottle. The rate of flow is then adjusted until the desired blood pressure level is obtained (In some cases, a more potent vasopressor, such as norepinephrine bitartrate, may be required). Hypertension should be avoided. The blood pressure should be checked frequently. Headache and/or bradycardia may indicate hypertension. Arrhythmias are rare.
Spinal Anaesthesia-Hypotension :
Routine parenteral use of Phenylephrine hydrochloride has been recommended for the prophylaxis and treatment of hypotension during spinal anaesthesia. It is best administered subcutaneously or intramuscularly 3 or 4 minutes before injection of the spinal anaesthetic. The total requirement for high anaesthetic levels is usually 3 mg and for lower levels, 2 mg. For hypotensive emergencies during spinal anaesthesia, Phenylephrine hydrochloride may be injected intravenously, using an initial dose of 0.2 mg. Any subsequent dose should not exceed the previous dose by more than 0.1 mg to 0.2 mg and no more than 0.5 mg should be administered in a single dose. To combat hypotension during spinal anaesthesia in children, a dose of 0.5 mg to 1 mg per 25 pounds body weight, administered subcutaneously or intramuscularly, is recommended.
Prolongation of Spinal Anaesthesia :
The addition of 2 mg to 5 mg of Phenylephrine hydrochloride to the anaesthetic solution increases the duration of motor block by as much as approximately 50 percent without any increase in the incidence of complications such as nausea, vomiting or blood pressure disturbances.
Vasoconstrictor for Regional Analgesia :
Concentrations about ten times those employed when adrenaline is used as a vasoconstrictor are recommended. The optimum strength is 1 : 20,000 (made by adding 1 mg of Phenylephrine hydrochloride to every 20 ml of local anaesthetic solution). Some pressor responses can be expected when 2 mg or more are injected.
Paroxysmal Supraventricular Tachycardia :
Rapid intravenous injection (within 20 to 30 seconds) is recommended; the initial dose should not exceed 0.5 mg and subsequent doses, which are determined by the initial blood pressure response, should not exceed the preceding dose by more than 0.1 mg to 0.2 m
Phenylephrine hydrochloride induces tachycardia or reflex bradycardia and should therefore be avoided in severe hyperthyroidism or in patients who are hypersensitive to it and in patients with severe hypertension.

If used in conjunction with oxytocic drugs, the pressor effect of sympathomimetic pressor amines is potentiated. The obstetrician should be warned that some oxytocic drugs may cause severe persistent hypertension and that even a rupture of a cerebral blood vessel may occur during the postpartum period. Phenylephrine hydrochloride Injection contains Sodium metabisulphite, a sulphite that may cause allergic-type reactions including anaphylactic symptoms and life-threatening or less severe asthmatic episodes in certain susceptible people. The overall prevalence of sulphite sensitivity in the general population is unknown and probably low. Sulphite sensitivity is seen more frequently in asthmatic than in nonasthmatic people.
Phenylephrine hydrochloride should be employed only with extreme caution in elderly patients or in patients with partial heart block, myocardial disease or severe arteriosclerosis.

Use in Pregnancy : 
Animal reproduction studies have not been conducted with Phenylephrine hydrochloride. It is also not known whether Phenylephrine hydrochloride can cause foetal harm when administered to a pregnant woman or can affect reproduction capacity. Phenylephrine hydrochloride should be given to a pregnant woman only if clearly needed.

Use in Lactation :
It is not known whether this drug is excreted in human milk. Because many are excreted in human milk, caution should be exercised when Phenylephrine hydrochloride is administered to a nursing woman.

Use in Labour :
If vasopressor drugs are either used to correct hypotension or added to the local anaesthetic solution, the obstetrician should be cautioned that some oxytocic drugs may cause severe persistent hypertension and that even a rupture of a cerebral blood vessel may occur during the postpartum period.

Paediatric  Use :
To combat hypotension during spinal anaesthesia in children, a dose of 0.5 mg to 1 mg per 25 pounds body weight, administered subcutaneously or intramuscularly, is recommended.

Vasopressors, particularly metaraminol, may cause serious cardiac arrhythmias during halothane anaesthesia and therefore should be used only with great caution or not at all.

MAO Inhibitors : 
The pressor effect of sympathomimetic pressor amines is markedly potentiated in patients receiving monoamine oxidase inhibitors (MAOI). Therefore, when initiating pressor therapy in these patients, the initial dose should be small and used with due caution. The pressor response of adrenergic agents may also be potentiated by tricyclic antidepressants.

Headache, reflex bradycardia, excitability, restlessness and rarely arrhythmias.

Overdosage may induce ventricular extrasystoles and short paroxysms of ventricular tachycardia, a sensation of fullness in the head and tingling of the extremities. The oral LD50 in the rat is 350 mg/kg, in the mouse 120 mg/kg.

Should an excessive elevation of blood pressure occur, it may be immediately relieved by an a-adrenergic blocking agent, e.g. phentolamine.

Parenteral drug products should be inspected visually for particulate matter and discoloration prior to administration, whenever solution and container permit.

Store below 30°C, protected from light. 
Do not refrigerate.

24 months from the date of manufacture.

NEFRISOL-P is supplied as 10 mg Phenylephrine hydrochloride in 1 ml aqueous solution. Each 1 ampoule is packed in a carton with package insert. Such 10 cartons are packed in a outer carton.


Disclaimer : For the use of a Registered Medical Practitioner or a Hospital or a Institution only. Also it is not intended to be used by healthcare professionals or patients for the purpose of prescribing or administering these products. Questions regarding the complete and current content of product labeling / specification / presentation should be directed to SGPharma.

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