A balance combination of agents with different actions is often used to provide the various components of general anesthesia including hypnosis muscle relaxation. This technique has been reported to minimize intra-operative cardiovascular depression, to facilitate a rapid return of consciousness, and to have a low incidence of postoperative adverse effects such as nausea, and vomiting, and excitation.

Antimuscarinics, including atropine, and hyoscine have been used as pre-operative medication to inhibit salivation and excessive secretions of the respiratory tract. This use is less important now that less irritating anesthetics are used. Atropine and hyoscine are also given as premedications to reduce intra-operative bradycardia and hypotension induced by agents such as suxamethonium, halothane, or following vagal stimulation.

At the end of surgery drugs are sometimes administered to accelerate recovery from the effects of the various agents used during anesthesia. Non-depolarizing muscle relaxants may be reversed with anticholinesterases such as neostigmine but concomitant administration of atropine is required to prevent bradycardia and other muscarinic actions developing.

Oxygen should be added routinely during anesthesia with inhalational agents, even when air is used as the carrier gas, to protect against hypoxia.

Atropine is now rarely used for premedication but still has an emergency role in the treatment of vagotonic side effects.

Hyoscine effectively reduces secretion and also provides a degree of amnesia, sedation and anti-emesis. Unlike atropine it may produce bradycardia rather than tachycardia. In some patients, especially the elderly, hyoscine may cause the central anti-cholinergic syndrome (excitement, ataxia, hallucinations, behavioral abnormalities and drowsiness).

Neostigmine is the specific drug for reversal of non-depolarizing (competitive) blockade. It acts with in one minute of intravenous injection and lasts for 20 to 30 minutes; a second dose may then be necessary. Atropine should be given before or with neostigmine in order to prevent bradycardia, excessive salivation; and other muscarinic actions of neostigmine.

Atropine Sulphate

Injection, 1 mg/ml in 1 ml ampoule

Indications:- as antisialagogue pre-anaesthetic medication to prevent or reduce salivation and respiratory tract secretions.

Cautions: - pregnancy, breastfeeding, in children and elderly patients. Caution is also needed in patients with hyperthyroidism, hepatic or renal disease, hypertension, tachyarrhythmias, congestive heart failure, coronary artery disease, gastric ulcer, esophageal reflex, and cardiac insufficiency. Extreme caution is required in patients with known or suspected GI-infection and with autonomic neuropathy. There should be caution also in debilitated patients with chronic pulmonary disease. Advise patients not to drive vehicle or operate machineries

Drug interactions:- atropine with antacids, antidiarrhoeals (adsorbent), other anticholinergic, cyclopropane anaesthesia, ketoconazole.

Side effects: - dryness of mouth, nose and throat, skin; constipation decreased sweating, redness or other signs of irritation at injection site, blurred vision, decreased salivary secretion (difficulty in swallowing), mydriatic effect (increased sensitivity of eyes to light), increased intraocular pressure, bradycardia followed by tachycardia, palpitation and arrhythmias.

Contraindications: - severe ulcerative colitis, obstructive disease of the GI tract e.g. pylorodeudonal stenosis, achalasia, cardiospasm, paralytic ileus or intestinal atony (especially in geriatric or debilitated patients), known hypersensitivity, angle-closure glaucoma, obstructive uropathy, myasthenia gravis.

Dose and Administration:

Storage: - store at room temperature protect from freezing.

Hyoscine Hydrobromide

Injection, 0.4 mg/ml, 0.6 mg/ml in 1 ml ampoule

Indications: - as antisialogogue preanaesthetic medication to prevent or reduce salivation and respiratory tract secretion.
Parentral administration of scopolamine in combination with morphine or mepridine is indicated in pre-anaesthesia to reduce excitement and produce amnesia.

Cautions: - pregnancy and breast-feeding, in children and elderly patients. Advice patients to avoid alcohol, driving vehicle and operating machineries.

Drug interactions: - antacids, antidiarrhoeals (adsorbents), other anticholinergics, cyclopropane anaesthesia, CNS depressants.

Contraindications: - angle closure glaucoma, pyloric obstruction, urinary bladder neck obstruction, tachycardia, paralytic ileus, hypersensitivity to the drug, ulcerative colitis.

Side effects: - constipation, decreased sweating, drowsiness, dryness of mouth, skin, throat and nose, loss of memory, redness or other signs of irritation at injection site.

Dose and Administration:

Adult -Prophylaxis of excessive salivation and respiratory tract secretion in anaesthesia: IM 0.2-0.6mg, 30 minutes to 1 hour before induction of anaesthesia.

Child - Prophylaxis of excessive salivation and respiratory tract secretion in anaesthesia: IM, administered 45 minutes - 1 hour before induction of anaesthesia. Children (4-7 months) - 0.1mg. Children (7months - 3 years) - 0.15mg, children (3-8 years) - 0.2mg, Children (8-12 years) - 0.3mg

Storage: - store at room temperature in light-resistant container, protect from light.

Neostigmine

Injection (Methylsulphate), 0.5 mg/ml, 2.5 mg/ml in 1 ml ampoule

Indications: for reversal of the effects of Non-depolarizing Neuromuscular blocking agents (e.g. tubocurarine, metocurine, gallamine or pancuronium) after surgery.

It is also indicated in the treatment of post-operative non-obstructive urinary retention.

It may be indicated for prevention and treatment of post-operative gastro intestinal ileus and prevention of postoperative distention and urinary retention.

Cautions: - caution should be taken during near term pregnancy, in elderly and in those patients with epilepsy, bronchial asthma, bradycardia, recent coronary occlusion, vagotonia, hyperthyroidism, cardiac arrhythmias, or peptic ulcer.

Drug interactions: - anticholinergics especially atropine and related compounds, local and some general anaesthetics such as chloroform, cyclopropane, enflurane, halothane, lidocaine; systemic aminoglycosides, succinylcholine or decamythonium; other cholinesterase inhibitors including demecarium, echothiopate isophlurophate, edrophonium; ganglionic blocking agents such as guanethidine, mecamylamine, trimethaphan; procainamide.

Side effects: - diarrhoea, increasing sweating, increasing of watering of mouth, nausea, vomiting, stomach cramp, frequent urge to urinate, increased bronchial secretion, miosis, bradycardia, bronchospasm, weakness, muscle cramp, fasciculation, hypotension.

Contraindications: - intestinal or urinary tract obstruction (mechanical), hypersensitivity to the drug or bromide, peritonitis, urinary tract infection.

Dose and Administration:
Adult -Antidote (to non-depolarizing neuromuscular blocking agents) after surgery

- IV- 0.5mg - 2mg administered slowly, repeated as required up to a total dose of 5mg.

Note: -0.6mg - 1.2mg of atropine is administered prior to or concurrently with neostigmine to counteract its muscarinic side effect.

- Prevention of post-operative distention or retention - IM or SC - 0.25mg immediately following surgery, repeated every four to six hours for 2 or 3 days.

- Prevention of post-operative distention - IM or SC- 0.5mg as needed.

- Prevention of urinary retention - IM or SC - 0.5mg; dose repeated every 3 hours for at least five doses after patient has voided or the bladder has been emptied.

Note: - If urination doesn’t occur within one hour following the initial - 0.5mg per dose, the patient should be catheterized.

Child - Antidote (to non-depolarizing Neuromuscular blocker) after surgery - IV, 0.04mg per kg of body weight administered with 0.02mg of atropine per kg of body weight.

Storage: - at room temperature. Protect from freezing and light.

Oxygen (white-colored cylinder)

Indications: - oxygen is given by inhalation to correct hypoxia in conditions causing under ventilation of the lungs, such as exacerbations of chronic bronchitis, pneumonia, or pulmonary oedema, where bronchospasm causes hypoxia, as in asthma, in extensive fibrosing alveolitis after general anaesthesia and in conditions where the oxygen content of the air breathed is inadequate as at high altitudes.

Cautions: - any fire or spark is highly dangerous in the presence of increased oxygen concentrations especially when oxygen is used under pressure.
Metal cylinders containing oxygen should be fitted with a reducing valve by which the rate of flow can be controlled.

Side effects: - CNS, toxicity (nausea, mood change, vertigo, twitching, convulsions, loss of consciousness), pulmonary toxicity (decease in vital capacity, cough, substernal distress, and later atelectasis), retinopathy of prematurity.

Dose and Administration: - by inhalation. It is administered by means of nasal catheter, facemask, endotracheal tube, or oxygen tent.

Concentration of oxygen in inspired anesthetic gases should never be less than 21 % sideline (carbondioxide absorbent).