Community Pharmacy Lecture 4 PDF

Lecture 4 Dr.Sahar Badr Associate prof. of Clinical Pharmacy  Constipation Definition: ▪ Constipation is defined as a change in the frequency of bowel movement from the normal for the patient. ▪ It is characterized by the passage of hard, dry stools with difficul...

Lecture 4 Dr.Sahar Badr Associate prof. of Clinical Pharmacy  Constipation Definition: ▪ Constipation is defined as a change in the frequency of bowel movement from the normal for the patient. ▪ It is characterized by the passage of hard, dry stools with difficulty in excretion and straining that is less frequently than by the person’s normal pattern. Normal bowel habit: ▪ In fact, the normal range may vary from three movements in 1 day to three in 1 week. Patients who are constipated will usually complain of hard stools which are difficult to pass and less frequent than usual. ▪ A sudden change, which has lasted for 2 weeks or longer, would be an indication for referral. Epidemiology Age: ▪ Constipation is common in all age groups, however; there is a higher prevalence in people ˃ 65 years of age. Gender: ▪ Women suffer from constipation more often than men. Causes: Constipation can be caused by many factors: Lifestyle: ▪ A diet insufficient in fiber, insufficient fluid intake, lack of exercise, and poor bowel habits can contribute to constipation. Medications: ▪ Narcotic analgesics, or anticholinergics (antidepressants, antihistamines). In addition, OTC drugs such as iron supplements, calcium- or aluminum-containing antacids, NSAIDs may contribute to constipation. Pregnancy: ▪ The increased size of the uterus, hormonal changes, intake of calcium- and iron-containing prenatal vitamins, and a reduction in physical activity are all considered contributing factors. Systemic disorders: ▪ Such as intestinal obstruction, tumor, inflammatory bowel disease, hypothyroidism, irritable bowel syndrome.  Associated Symptoms ▪ Constipation is often associated with abdominal discomfort, bloating and nausea. ▪ In some cases constipation can be so severe as to obstruct the bowel. ▪ This obstruction or blockage usually becomes evident by causing colicky abdominal pain, abdominal distension and vomiting. ▪ When symptoms suggestive of obstruction are present, urgent referral is necessary.  Blood in the Stool ▪ The presence of blood in the stool can be associated with constipation. ▪ In such situations blood may arise from piles (hemorrhoids) or a small crack in the skin on the edge of the anus (anal fissure). ▪ Both these conditions are thought to be caused by a diet low in fiber that tends to produce constipation. ▪ If piles are present, there is often discomfort on defecation. ▪ A fissure tends to cause less bleeding but much more severe pain on defecation.  Diet ▪ Insufficient dietary fiber is a common cause of constipation. ▪ Changes in diet and lifestyle, e.g. following a job change, loss of work, retirement or travel, may result in constipation. ▪ It is thought that an inadequate fluid intake is one of the commonest causes of constipation. ▪ An adequate fluid intake is essential for well-being, and for both prevention and treatment of constipation. ▪ It is effective when water is increased alongside an increase in dietary fiber. ▪ The recommended daily amount of fluid is 2.5 liters a day for adults and not all of this need to be in the form of water.  Medications ▪ Continuous use, especially of stimulant laxatives, can result in a vicious circle where the contents of the gut are expelled, causing a subsequent cessation of bowel actions for 1 or 2 days. ▪ This then leads to the false conclusion that constipation has recurred and more laxatives are taken and so on. ▪ Chronic overuse of stimulant laxatives can result in loss of muscular activity in the bowel wall (an atonic colon) and thus further constipation. ▪ Many drugs can induce constipation; some examples are listed:  Analgesics and opiates: Dihydrocodeine, codeine  Antacids :Aluminium salts  Anticholinergics: Hyoscine  Anticonvulsants: Phenytoin  Antidepressants: Tricyclics, selective serotonin reuptake inhibitors  Antihistamines: Chlorpheniramine, promethazine  Antihypertensives: Clonidine, methyldopa  Anti-Parkinson agents: Levodopa  Beta-blockers: Propranolol  Iron  Laxative abuse  Monoamine oxidase inhibitors  Antipsychotics: Chlorpromazine  When Refer to GP ▪ Change in bowel habit of 2 weeks or longer. ▪ Presence of abdominal pain, vomiting, bloating. ▪ Blood in stools. ▪ Prescribed medication suspected of causing symptoms. ▪ Failure of OTC medication.  Management Treatment timescale: ▪ If one week use of treatment does not produce relief of symptoms, the patient should see the doctor. Non pharmacological management: ▪ Increasing the amount of dietary fiber, maintaining fluid consumption and doing regular exercise. ▪ Bowel training to increase regularity (i.e., allowing regular and adequate time for defecation). ▪ A diet rich in NSPs (non starch polysacchrides) and with plenty of water is likely to prevent constipation. ▪ In the short term, a laxative may be recommended to ease the immediate problem.  Pharmacological Treatment ▪ Treatment begins as a step-wise approach with bulk-forming laxatives as first line, osmotic laxatives as second line, and then stimulant laxatives if the previous recommendations were ineffective or intolerable. ▪ Self-care for the treatment of constipation should be limited to 7 days.  Classification of Laxatives ▪ Classification of laxatives according to mechanism of action:  Stimulant Laxatives  Bulk Laxatives  Osmotic Laxatives  Emollient Laxatives  Saline Laxatives  Lubricant Laxatives  Stimulant Laxatives ▪ They work by altering water and electrolyte transport by the intestines and by stimulating/increasing bowel motility (peristaltic activity). ▪ They are recommended when an individual has failed or is intolerant to bulk-forming or osmotic agents. However, stimulant laxatives are being used more frequently as first-line therapy for opiate-induced chronic constipation. ▪ Examples: Anthraquinones (senna, sennosides), Diphenylmethane (bisacodyl). ▪ The action of oral preparation is within 6 to 12 h, but the rectal preparation is quicker, within 15 to 60 minutes. ▪ They should not be used for more than one week. ▪ The intensity of the laxative effect is related to the dose taken. ▪ Senna can be taken as single-entity products or combined with a stool softener. It is appropriate for self-care for pediatrics (ages 2 and older). ▪ Bisacodyl tablets are enteric coated and should be swallowed whole because bisacodyl is irritant to the stomach. ▪ The use of senna pods and cascara, which is non-standardized, should be discouraged because the dose and therefore action are unpredictable. ▪ Castor oil is a traditional remedy for constipation, which is no longer recommended since there are better preparations available.  Stimulant Laxatives Warnings and Counseling Points ▪ Individuals with undiagnosed rectal bleeding or signs of intestinal obstruction should not use stimulant laxatives. ▪ Cathartic colon, which results in a poorly functioning colon, has been associated with the chronic use of stimulant laxatives. ▪ Sennosides may cause discoloration of the urine (pink/red, yellow, or brown), but this is a harmless effect. ▪ Tablet formulations of bisacodyl should not be crushed or chewed due to the enteric coating. ▪ Milk, H2RA (ranitidine, cimetidine, famotidine) and antacids may erode this enteric coating and should be separated in dosing by at least 1 hr.  Bulk Laxatives ▪ Bulk laxatives are those laxatives of choice. ▪ Bulk agents are especially useful where patients cannot or will not increase their intake of dietary fiber. ▪ Bulk laxatives work by swelling in the gut (absorb water to soften the stool and increasing fecal mass (bulk) so that peristalsis is stimulated. ▪ The laxative effect is slow and can take several days to develop. ▪ The sodium content of bulk laxatives (sodium bicarbonate) should be considered in those requiring a restricted sodium intake. ▪ Examples: methylcellulose, psyllium (or ispaghula), calcium polycarbophil, wheat dextran ▪ When recommending the use of a bulk laxative, the pharmacist should advise that an increase in fluid intake would be necessary. ▪ In the form of granules or powder, the preparation should be mixed with a full glass of liquid (fruit juice or water) before taking. ▪ Intestinal obstruction may result from inadequate fluid intake in patients taking bulk laxatives, particularly those whose gut is not functioning properly as a result of abuse of stimulant laxatives.  Bulk Laxative Warning and Counseling Points ▪ Bulk-forming agents should not be used if:  An obstructing bowel lesion  Intestinal strictures  Crohn’s disease  Severe fluid restrictions, such as those with heart failure or renal impairment. ▪ Sugar-free formulations should be considered for individuals with diabetes. ▪ The use of bulk-forming laxatives for constipation relief should be limited to 1 week; however, they can be used on a long-term basis for prevention. ▪ They should not be used for children less than 6 years.  Osmotic Laxatives ▪ They work by creating an osmotic gradient to pull water into the small and large intestines, resulting in increased peristalsis and bowel motility. ▪ Examples: Glycerin suppositories and polyethylene glycol, epsom salts (magnesium sulfate), lactulose. ▪ Glycerin suppositories have an onset range of 15 minutes to 1 h and polyethylene glycol has a longer onset of 1 to 3 days. ▪ Glycerin causes rectal burning and polyethylene glycol at excessive doses may cause diarrhea, nausea, bloating, cramping, and flatulence. Lactulose ▪ Lactulose works by maintaining the volume of fluid in the bowel. ▪ It may take 1–2 days to work. ▪ The contents of the sachet are sprinkled on food or taken with liquid. ▪ One or two glasses of fluid should be taken with the daily dose. ▪ Lactulose and lactitol can cause flatulence, cramps and abdominal discomfort. Epsom salts ▪ Epsom salts (magnesium sulphate) is a traditional remedy that, while no longer recommended, is still requested by some older customers. ▪ It acts by drawing water into the gut; the increased pressure results in increased intestinal motility. ▪ A dose usually produces a bowel movement within a few hours. ▪ Repeated use can lead to dehydration.  Emollient Laxatives (Surfactants-Stool Softeners) ▪ It is also known as surfactants/stool softeners, work by allowing water to move more easily into the stool. This creates a softer stool, which is easier to pass. ▪ These agents are useful in those who must avoid straining (i.e. exertion) to pass hard stools (recent myocardial infarction, rectal surgery). ▪ Emollient laxatives have very few side effects, but they are not as effective as other laxatives. ▪ Examples: Docusate sodium (dioctyl sulfosuccinate sodium, DOSS), docusate calcium. ▪ Onset: Slow (24 to 72 hours) ▪ Each dose should be taken with at least 8 fl-oz of water.  Saline laxatives ▪ It works by drawing water into the colon. ▪ Examples: Magnesium citrate, Magnesium hydroxide, Sodium phosphate. ▪ Onset: 30 minutes to 3 h when given orally and 2 to 5 minutes when given rectally. ▪ Side effects: Abdominal cramping, excessive diuresis, nausea, vomiting, and dehydration, hypermagnesemia in patients with preexisting renal impairment, diarrhea. ▪ Sodium-containing salts should be avoided in those individuals with sodium restrictions (heart failure, edema, renal failure). ▪ Oral sodium phosphate (OSP): may cause acute phosphate nephropathy (acute kidney injury) , FDA has determined that OSP products are not appropriate for bowel cleansing.  Lubricant Laxative ▪ It works at the colon to increase water retention in the stool. ▪ Examples: Mineral oil ▪ Onset: 6 to 8 hr (oral dosing) and 5 to 15 min (rectal dosing). ▪ Mineral oil can decrease absorption of fat-soluble vitamins (vitamins A, D, E, K), so it should not be used on a chronic basis. ▪ Mineral oil should be taken on an empty stomach. Because of possible aspiration of mineral oil into the lungs (lipid pneumonitis), this agent should not be taken at bedtime. Those who are elderly, or have dysphagia are at the greatest risk of lipid pneumonitis. ▪ Emollient and lubricant laxatives should not be given concomitantly as they increase the systemic absorption of mineral oil, which can lead to hepatotoxicity. ▪ Mineral oil is contraindicated in persons with rectal bleeding, appendicitis or age ˂6 years.  Constipation in Children ▪ Numerous factors can cause constipation in children, including a change in diet and emotional causes. ▪ Simple advice about sufficient dietary fiber and fluid intake may be all that is needed. ▪ A single glycerin suppository together with dietary advice may be appropriate. ▪ Referral to the doctor would be best if these measures are unsuccessful.  Constipation in Elderly ▪ Constipation is a common problem in elderly patients for several reasons. ▪ Elderly patients are less likely to be physically active; they often have poor natural teeth or false teeth and so may avoid high-fiber foods that are more difficult to chew; multidrug regimens are more likely in elderly patients, who may therefore suffer from drug-induced constipation. ▪ If a bulk laxative is to be recommended for an elderly patient, it is of great importance that the pharmacist give advice about maintaining fluid intake to prevent the possible development of intestinal obstruction.  Constipation in Pregnancy ▪ Constipation commonly occurs during pregnancy; hormonal changes are responsible. ▪ Dietary advice concerning the intake of plenty of high-fiber foods and fluids can help. ▪ Oral iron, often prescribed for pregnant women, may contribute to the problem. ▪ Stimulant laxatives are best avoided during pregnancy; ▪ Bulk-forming laxatives are preferable.  Laxative Abuse ▪ Two groups of patients are likely to abuse laxatives: ▪ Those with chronic constipation who get into a vicious circle by using stimulant laxatives, which eventually results in damage to the nerve plexus in the colon. ▪ Those who take laxatives in the belief that they will control weight, e.g. those who are dieting or women with eating disorders (anorexia nervosa or bulimia nervosa), who take very large quantities of laxatives.