Drug Interaction:
Antiadrenergic agents ( Peripherally acting )include- Reserpine, Guanithidine monosulphate, Guandrel sulfate, ( Alpha-1- blockers), Prazosin,Terazosin, Doxazosin, Tamsulosin, Silodosin, Alfuzosin Hcl Refer - Prazosin
Interacting drugs with Guanadrel-
Betablockers- Phenothiazines decr Sympathomimetics incr Tricyclic antidepressants decr Vasodilators incr
with Guanadrel-
Beta blockers - increase effects of guanadrel may be potentiated, causing excessive postural hypotension and bradycardia
Phenothiazines- decrease effects of guanadrel may be reversed
Sympathomimetics- decrease hypotensive effect of guanadrel may be reversed
Guanadrel- increase guanadrel may potentiate the effect of direct acting sympathomimetics
Tricyclic antidepres- decrease TCAs may block norepinephrine depleting effect and the blood pressure lowering effect of guanadrel. Use caution with cocomittant use
Vasodilators- increase concomittant use may increase the potential for symptomatic orthostatic hypotension and is generally not recommended
Indication:
Hypertension
Antiadrenergic agents ( Peripherally acting )include- Reserpine, Guanithidine monosulphate, Guandrel sulfate, ( Alpha-1- blockers), Prazosin,Terazosin, Doxazosin, Tamsulosin, Silodosin, Alfuzosin Hcl Refer - Prazosin
I
Adverse Reaction:
Cardiovascular/Respiratory- Shortness of breath, palpitations, chest pain, coughing, shortness of breath at rest.
CNS- Fatigue, headache, faintness, drowsiness, visual disturbances, visual disturbances, paresthesis, confusion, psychological problems, depression, sleep disorders, syncope
GI- Increased bowel movements, gas pain, indigestion, anorexia, glossitis, nausea/vomiting, dry mouth, dry throat, abdominal distress or pain
GU- nocturia, urination urgency, or frequency,peripheral edema, ejaculation disturbances, impotence, hematuria
Miscellaneous- Excessive weight gain/loss, aching limbs, leg cramps-night time, and at day time, backache or nechache, joint pain.
Contra-Indications:
Known or suspected pheochromocytoma, hypersens to guanadrel
Special Precautions:
Salt and water retention may occur. Patients with CHF have not been studied,but guanadrel could interfere with the adrenergic mechanisms.
Peptic ulcer- use guanadrel with caution with caution in patients with a history of peptic ulcer, which could be aggrevated by a relative increase in parasympathetic tone.
Warnings-
Orthostatic hypotension- and its consequences (dizziness and weakness ) are frequent. Rarely fainting upon standing or excercise occurs. careful instructions to patients can mimimize symptoms, supine blood pressure is not an adequate assessment.
Surgery- to reduce the possibilitybof vascular collapse during anesthesia, discontinue guanadrel 48 to 72 hours before elective surgery.
Asthma- special care is required in patients with bronchial asthma, as it may be aggravated by catecholamine depletion and sympathomimetic amines may interfere with the hypotensive effect of guanadrel.
Renal function impairment- dosageadjustments may be necessary ,especially in patients with creatinine clearances CrCr < 60ml/min Pregnancy- use only when clearly needed and when the potential benefits outweigh the potential hazards to the fetus.
Lactation- because ofthe potential for serious adverse reactions in nursing infant, decide whether to discontinue nursing or to discontinue the drug taking into account the importance of the drug to the mother.
Children- safety and efficacy for use in children have not been established.
Dosages/ Overdosage Etc:
Indications:
Hypetension
Dosage:
Individualise dosage. Usual starting dose is 10mg/day, which may be given as 5mg 2 times a daily by breaking the 10mg tablet. Mostpatients will require a daily dosage of 20 to 75mg usually twice daily. For larger doses 3 or 4 times daily dosing may be required.
Overdosage-
Symptoms-
Marked dizziness and blured vision related to postural hypotension progressing to syncope on standing. The patient should lie down until these symptoms subside
Treatment
1. If excessive hypotension occurs and persists despite conservative treatment a vasoconstrictor such as phenylephrine may be needed, but use carefully because patients may be hypertensive to such agents.
Missed dose
1. If you miss a dose of this medicine, take it as soon as possible.
2. However, if it is almost time for next dose, skip the missed dose and go back to your regular dosing schedule.
3. Do not double doses.
Patient Information:
GUANADREL SULPHATE- ANTIADRENERGIC AGENTS
1. The medication may cause orthostatic hypotension, sit or lie down immediately at the onset of dizziness or weakness to prevent loss of consciousness. Postural hypotension is worst in the morning and upon arising, and may be exaggerated by alcohol, fever, hot weather, prolonged standing or exercise.
2. Do not take any prescription or over the counter medications, especially medications for treatment of colds, allergy or asthma, without physicians or pharmacists advice
3. Allergy- Tell your doctor if you had any unusual reaction to guanadrel. Also tell yor doctor if you you are allergic to any food substances, preservatives, dyestuffs
4. Pregnancy- Not studied in pregnant women. Guanadrel notshown to caus birth defects or other problems in animal studies
5. Breast feeding- Not known whether guanadrel passes into breast milk. Not reported to cause problems in nursing babies
6. Chldren- Studies done only in adults. No specific information comparing use of guanadrel in children with use in other age groups.
7. Older adults- dizziness, fainting, more likelyto occur in elderly, who are more sensitive to effects of guanadrel
8. Other medicines- Tell your doctor if you taking any of the following medicines- Chlorprothixee or Loxapine or Thiothixene or Trcyclic antidepressants or Trimeprazine - may decrease the efects of guanadrel on blood pressure MAOI- taking guanadrel while you are taking or within 1 week of taking MAOI may cause a severe increase in blood pressure
9. Other medical problems- Tell your doctor if you are having any of the following - Asthma or Diarrhea or Pheochrmocytoma or Stomach ulcer - guanadrel may worsen these conditions Fever -effectsof guanadrel may beincreased Heart attack or stroke or Heart or blood vessel disease - lowering of blood pressure may make problems resulting from these conditions worse
10. Dosing- Follow doctors instructions
11. Missed dose- If you miss a dose of this medicine take it as soon as possible. However if it is almost time for your next dose go back to your regular dosing schedule. Do not double doses.
12. Storage- Keep the medicines out of reach of children Store the medicines away heat and direct light Do not store tablets or capsules in the bath room, in damp places near the kitchen sink Heat and dampness will cause the medicines to break down Keep the medicine from freezing
Pharmacology/ Pharmacokinetics:
Antiadrenergic agents ( Peripherally acting )include- Reserpine, Guanithidine monosulphate, Guandrel sulfate, ( Alpha-1- blockers), Prazosin,Terazosin, Doxazosin, Tamsulosin, Silodosin, Alfuzosin Hcl Refer - Prazosin
Pharmacology:
Guanadrel structurally and pharmacologically is similar to guanethidine. It inhibits sympathetic vasoconstriction by inhibiting norepinephrine release from neuronal storage sites in response to erve stimulation. Guanadrel begins to decrease blood pressure within 2 hours and produces maximum decreases in 4 to 6 hours.
Pharmacokinetics:
It is rapidly absorbed after oral administration.Plasma concentrations generally peaks 1.5 to 2 hours after ingestion.
Interaction with Food:
Not available
Pregnancy and lactation:
Pregnancy:
Use only when clearly needed and when the potential benefits outweighs the hazards to the fetus.
Lactation:
Excercise caution while administering the drug.
Children-
Safety and efficacy for use in children have not been established.
