medicines management: constipationhow do these laxatives work? bulk-forming laxative –increases...

Medicines Management:ConstipationSamuel Taylor

Clinical Pharmacist

Medicines Optimisation in Care Homes Team

Overview

How do the medications work that we use for constipation?

Which medications contribute to constipation and why?

A few tips for using laxatives appropriately

How can we help to prevent constipation?

Homely Remedies & Pharmacy

How many laxatives can you name?

• Bisacodyl e.g. Dulcolax

• Docusate sodium e.g. DulcoEase

• Glycerol

• Ispaghula husk e.g. Fybogel

• Lactulose

• Macrogols e.g. Cosmocol, Laxido, Movicol

• Methylcellulose e.g. Celevav

• Senna

• Sodium citrate e.g. Micralax, Relaxit

• Sodium picosulphate e.g. Dulcolax Pico

• Sterculia e.g. Normacol

Less commonly prescribed:

• Co-danthramer/Co-danthrusate

• Linaclotide e.g. Constella

• Naloxegol e.g. Moventig

• Prucalopride e.g. Resolor

Key:

Bulk-forming laxative

Osmotic laxative

Other (specific individuals actions)

Stimulant laxative

Stool softening

How many laxatives can you name?

• Others:

• Medications increasing gastric motility (movement)

• Domperidone and Metoclopramide

• MHRA guidance recommends maximum 5-day use of Metoclopramide.

• Due to risk of neurological effects such as extrapyramidal disorders and tardive dyskinesia NOT to be used in those under 18

• MHRA guidance recommends maximum 7-day use of Domperidone.

• Use lowest dose for the shortest time period possible

• Not to be used in those under 35kg or children under 12

• Risk of cardiac side-effects – report any signs of arrhythmia immediately

How do these laxatives work?

Bulk-forming laxative – increases volume and mass of stool in colon, this activates ‘stretch receptors’ which send chemical signals to the brain to encourage defaecation. Also creates a thick mucus layer in intestinal lining to ease movement of stool.

Osmotic laxative – retains water in the bowel by osmosis (movement of water across a semi-permeable membrane). Increased water content in bowel creates a soft and smooth stool.

Stimulant laxative – stimulates movement in the large intestine (to promote stool movement into rectum) +/- can increase fluid/water content in colon via inhibition of water absorption from bowel.

Stool softener – lowers the surface tension of the stool which allows water to move into hard, dry faeces.

Mg2+ (magnesium) is present in some osmotic laxatives.

Cholecystokinin (CCK) is a peptide hormone of the gastrointestinal system responsible for stimulating the digestion of fat and protein.

(Nerves within intestine walls)

Laxido, Movicol, Cosmocol etc.

Which medications can cause constipation?

• Aluminium (in antacids)

• Anti-cholinergics e.g. amitriptyline, hyoscine, oxybutynin, tolterodine

• Anti-diarrhoeals e.g. loperamide

• Calcium e.g. adcal, antacids

• Calcium-channel blockers e.g. Diltiazem, verapamil

• Clozapine

• Iron e.g. ferrous sulphate/fumarate

• Methylcellulose

• Proton pump inhibitors e.g. lansoprazole, omeprazole

• Opioids

• Codeine

• Buprenorphine

• Dihydrocodeine

• Fentanyl

• Morphine

• Oxycodone

• Tramadol

Case study: Anti-cholinergics

• Reduce transmission of acetylcholine either intentionally or as a side-effect.

But why do they cause constipation?

• Usually acetylcholine works on the parasympathetic nervous system (PNS).

• The rest & digest system

• The PNS stimulates movement of food contents in gut and promotes secretion of water/salts to aid flow of gut contents.

• Reduced acetylcholine means reduced gut contents movement and less water/salt release.

= Constipation

Top tips for use for laxatives

Osmotic laxatives need 24-48hrs to have the desired effect.

Ispaghula husk should not be given immediately before bed as the contents swells in the stomach. Avoid giving 2 hours before bed.

Methylcellulose is used for both constipation and diarrhoea, to treat constipation a 300mL intake of fluid is needed with the medication.

Don’t stop natural methods when laxatives are in use –continue to offer fibre-based foods, plenty of fluids and encourage exercise.

Stimulant laxatives work within 8-14 hours, thus give at NIGHT to promote bowel movement in the morning.

Lactulose – do not offer to those with severe lactose intolerance.

Prevention of constipation

Medication is NOT always the answer in the first instance

Exercise and/or mobilising -> anything is better than nothing

Healthy diet -> see factsheets available

Monitor fluid intake -> the less fluid intake, the higher risk of constipation

Reducing polypharmacy (i.e. unnecessary medications) -> prompt your GPs/Clinical Pharmacists!

Using laxatives in preparation for constipation e.g. post-surgery, initiation of opioids

Identifying those at high risk of constipation via care plan and initiating bowel monitoring

Homely Remedies

Review your homely remedy policy and see which laxatives are available

• Are you comfortable with when to administer?

• Is the dosing clear?

• Does it cover all residents?

• Always document administration on reverse of MAR with explanation e.g. Lactulose 10mL given as resident reporting constipation.

• Further detail in care plan – 10mL twice daily of laxative for 48 hours, if no resolution we will need to contact GP.

• Bowel chart/monitoring in place.

Want some further advice?

• Call your local community pharmacy or your supplying pharmacy and ask to speak to the pharmacist.

• They will want to know their regular medications and current issues/concerns:

• Can sell you laxatives if needed and authorise their use.

• If they cannot answer your query or feel it warrants further investigation, they will ask you to contact the GP or 111.

What laxatives could you have on homely remedies?

The following can be purchased over-the-counter:

• Senna (liquid or tablets)

• Lactulose (liquid)

• Docusate (capsules or liquid)

• Macrogols (liquid or powder sachets) -> Laxido®, Movicol®, Cosmocol ®

• Glycerol suppositories (nursing as require PR administration)

• Bisacodyl (tablets or suppositories)

• Ispaghula husk (powder sachets) -> Fybogel®

• Sodium picosulfate (liquid)

Some warning signs for immediate GP referral• Blood/mucus in or around stool or rectum

• Pregnancy

• Severe abdominal pain e.g. guarding or vocalisation

• Medication-induced constipation

• Constipation associated with nausea and vomiting

• Unintentional weight loss

• Overflow diarrhoea

• Failed self-care interventions e.g. use of homely remedies

• Intense straining

• Very bloated stomach

MHRA Drug Safety Update: August 2020

• MHRA – Medicines and Healthcare products Regulatory Agency

• The safety of stimulant laxatives has been under close review by the MHRA formany years following concerns relating to misuse and abuse. Previousmeasures have included the addition of warnings to some products to advisethat laxatives do not aid weight loss and that long-term use may be harmful.

• We have introduced pack size restrictions, revised recommended ages for use,and new safety warnings for over-the-counter stimulant laxatives (orally andrectally administered) following a national safety review.

• Advise patients that dietary and lifestyle measures should be used first-linefor relieving short-term occasional constipation and that stimulant laxativesshould only be used if these measures and other laxatives are ineffective.

Which laxative is which?

Which laxative is which?

Osmotic

Osmotic

Stimulant

Bulk-forming

Softener & Stimulant