1. The main aim of anaesthesia is the prevention of pain during surgery and at other times.
2. Anaesthesia involves a balanced approach, in which the individual patient’s psyche and pathophysiology are taken into account and drugs are used to modify and control any aspect as required.
3. The decision to use a particular drug or technique must be made after careful consideration of the pathophysiological features of the individual case and how these may affect the phar­macokinetic handling and tissue response to the drugs available.
4. Any associated disease or pathophysiological abnormality should wherever possible be treated or corrected before operation, and potentially dangerous physiological disturbances avoided during and after anaesthesia.
5. Anaesthetic drugs are relatively non-toxic but there are some important effects. Halothane is occasionally associated with hepatitis and methoxyflurane with kidney damage. Malignant hyperpyrexia, the aetiology of which is uncertain, is a rare but often fatal condition which can be triggered off by several anaesthetic drugs in genetically susceptible individuals.
6. Drugs used in anaesthesia can be involved in significant unwanted interactions with other drugs.
7. The treatment of respiratory failure is usually the responsibility of the anaesthetist. Although ventilatory assistance, physiotherapy, etc. are often the mainstay of treatment, drugs of different pharmacological classes are used.
8. Pain perception is an individual sensation. Symptomatic treatment of acute pain should not therefore be based on a concept of the painfulness of certain conditions, although some anal­gesics may be more appropriate for pain of certain conditions.
9. Strong analgesics for severe chronic pain should preferably be given orally, in adequate dosage, and on a regular individualised dosage schedule.

General Considerations

Although achieving insensibility to pain and to unpleasant surroundings has been the goal of much human activity since prehistoric times, it is only since 1846 with the introduction of ether by Morton that this could be done with any re­liable chance of success. Anaesthesia has devel­oped and been refined considerably since that time, and several important milestones are re­cognized and worthy of recall. These include the discovery of the local anaesthetic action of co­caine by Koller in 1884 and its use to produce spinal anaesthesia by Bier in 1898, the perfec­tion of endotracheal anaesthesia by Magill and Rowbotham about 1920, the introduction of the first barbiturate for induction of anaesthesia in 1932, and the introduction of curare in 1942.
In recent years, the specialty of anaesthesia has been broadened, and its scope is well de­scribed in a definition for the US Department of Labor (Dripps 1966):

Anesthesiology is a practice of medicine dealing with:

• The management of procedures for ren­dering a patient insensible to pain during surgical procedures.
• The support of life functions under the stress of anesthetic and surgical manipu­lations.
• The clinical management of the patient unconscious from whatever cause.
• The management of problems in pain re­lief.
• The management of problems in cardiac and respiratory resuscitation.
• The application of specific methods of inhalational therapy.
• The clinical management of various fluid electrolyte and metabolic disturbances.

The modern concept is one of ‘balanced an­aesthesia’, in which the whole of the patient’s psyche and pathophysiology are taken into ac­count and drugs are used to modify and control any aspect as required. Thus, as well as general anaesthetic agents, drugs of many classes – tran­quillisers, analgesics, muscle relaxants, drugs af­fecting the autonomic system etc. – all fall within the sphere of interest of the anaesthetist. ( Some of the more important of these will be discussed further at later part – Drugs Used in Anaesthesia .)

• Hypertension ( high blood pressure ),
• heart failure,
• diabetic kidney disease,
• and heart attack treatment ( when the function of the left ventricle has been affected),
• kidney failure,
• kidney hypertension,
• managing people with a high risk of heart disease,
• chronic kidney disease,
• preventing a second stroke.

General Information of the drug

• Enalapril begins working about 1 hour after you take it and continues to work for 24 hours.
• Enalapril maleate and other ACE inhibitors work by preventing the conversion of a hormone called ‘Angiotensin I‘ to another hormone called ‘Angiotensin II‘ , a potent blood-vessel constrictor. Preventing this conversion relaxes blood vessels, thus reducing blood pressure and relieving symptoms of heart failure.
• Enalapril also affects the production of other hormones and enzymes that participate in the regulation of blood-vessel dilation.

Cautions

• Enalapril occasionally causes very low blood pressure.
• Do not take enalapril if you are allergic or sensitive to any of its ingredients. Severe sensitivity reactions can occur in hemodialysis patients taking enalapril or those undergoing venom immunization.
• Swelling of the face, extremities, or throat has been known to occur with enalapril, which can be dangerous (see below section on “Important Notes” ).
• Enalapril may affect your kidney function, especially if you have congestive heart failure. Your doctor should check your urine for protein content during the first few months of treatment. Dosage adjustment of enalapril is necessary if you have reduced kidney function.
• Enalapril can affect white-blood-cell counts, possibly increasing your susceptibility to infection. Your doctor should monitor your blood counts periodically.
• Enalapril may cause serious injury or death to the fetus if taken during pregnancy. Pregnant women should not take enalapril.
• ACE inhibitors may be less effective in some black patients with high blood pressure, especially when dietary salt intake is high. Nevertheless, they should still be considered useful blood pressure treatments. Swelling beneath the skin to form welts is more common among black patients.

How the Drug works ?

• Antacids and enalapril should be taken at least 2 hours apart.
• The blood-pressure-lowering effect of enalapril is additive with diuretic drugs and beta blockers. Any other drug that causes a rapid drop in blood pressure should be used with caution if you are taking enalapril.
• Enalapril may increase the effects of lithium; this combination should be used with caution.
• Aspirin and other nonsteroidal anti-inflammatory drugs (NSAIDs) reduce the blood-pressure-lowering effects of enalapril and other ACE inhibitors. The combination may cause reductions in kidney function.
• Enalapril may increase blood-potassium levels, especially when taken with dyazide or other potassium-sparing diuretics.
• Capsaicin may trigger or aggravate the cough associated with enalapril therapy.
• Rifampin may reduce the effects of enalapril.
• The combination of allopurinol and enalapril increases the chance of side effects. Avoid this combination as severe sensitivity reactions can occur in those taking allopurinol.
• Enalapril affects blood levels of digoxin. More digoxin in the blood increases the chance of digoxin-related side effects, while less digoxin in the blood can compromise its effectiveness.
• Indomethacin may reduce the blood-pressure-lowering effects of enalapril.
• Phenothiazine sedatives and antiemetics may increase the effects of enalapril.

Important Note

• Enalapril can cause swelling of the face, lips, hands, or feet. This swelling can also affect the larynx (throat) or tongue and interfere with breathing. If this happens, go to a hospital emergency room at once.
• Call your doctor if you develop a sore throat, mouth sores, abnormal heartbeat, chest pain, persistent rash, or loss of taste perception.
• Some people who start taking enalapril after they are already on a diuretic (an agent that increases urination) could experience a rapid drop in blood pressure after their first doses or when their dosage is increased. To prevent this from happening, inform your doctor before hand ( that you are taking diuretic ) , as your doctor may tell you to stop taking your diuretic 2 or 3 days before starting enalapril or to increase your salt intake during that time. Upon your doctor advise, you may then restart on taking diuretic gradually.
• You may get dizzy if you rise to your feet too quickly from a sitting or lying position when taking enalapril.
• Avoid strenuous exercise or very hot weather because heavy sweating or dehydration can cause a rapid drop in blood pressure.
• While taking enalapril, avoid over-the-counter diet pills, decongestants, and other stimulants that can raise blood pressure.
• Do not take potassium supplements or salt substitutes containing potassium without consulting your doctor.
• Never take a double dose. If you take enalapril once a day and forget to take a dose, take it as soon as you remember. If it is within 8 hours of your next dose, skip the one you forgot and continue with your regular schedule. If you take enalapril twice a day and miss a dose, take it right away. If it is within 4 hours of your next dose, take 1 dose immediately and another in 5 or 6 hours, then go back to your regular schedule.

Possible Side Effects

Refers to Side Effects on Lexxel Drug , as these drugs works in combination in most treatments condition. However, if you experience unusual effects, do consult your doctor for advise.

Pregnancy/Breast-feeding period :

• ACE inhibitors can cause fetal injury or death. Women who are or might become pregnant should not take ACE inhibitors.
• Sexually active women of childbearing age who must take enalapril must use an effective contraceptive method to prevent pregnancy.
• If you become pregnant, stop taking the medication and call your doctor immediately.
• Nursing mothers who must take this drug should use infant formula as small amounts of enalapril pass into breast milk.

For Seniors who needs to take this drug :-

Seniors may be more sensitive to the effects of enalapril drug due to age-related losses in kidney or liver function.