The Drug Recognition Guide. Mark Currivan

      Note a few exceptions: drugs with names ending in ‘‐tidine’ but which are not H2‐receptor antagonists: azacitidine (a chemotherapy drug: see Chapter 10) and hexetidine (an antiseptic mouth wash).

Laxatives

      Laxatives (also known as aperients or purgatives) are given to treat or prevent constipation. There are various types: bulk‐forming laxatives (i.e., ispaghula husk and sterculia) that act by increasing faecal mass; osmotic laxatives (i.e., lactulose) that draw water into the bowel; faecal softeners (i.e., docusate sodium and poloxamer ‘188’) that ease rectal straining and stimulant laxatives (i.e., bisacodyl, dantron, senna and sodium picosulfate) that promote peristalsis and bowel motility. Co‐danthramer (which combines dantron with poloxamer ‘188’) and co‐danthrusate (which combines dantron with docusate sodium) are both compound laxatives (hence their ‘co‐’ prefix). Prucalopride is a selective 5HT‐4 receptor agonist: it promotes bowel motility by enhancing the transmission of serotonin‐4 (5HT‐4) to 5HT‐4 receptors in the colon.

       Bisacodyl

       Co‐danthramer

       Co‐danthrusate

       Docusate sodium

       Ispaghula husk

       Lactulose

       Prucalopride

       Senna

       Sodium picosulfate

       Sterculia

      Do not confuse dantron (a component of both co‐danthramer and co‐danthrusate) with the antiemetic ondansetron (see Chapter 7). Similarly, do not mistake the laxative prucalopride for a benzamide class antipsychotic (i.e., amisulpride, see Chapter 5).

Proton pump inhibitors (PPIs)

The parietal cells in the stomach release a stream of enzymes known as the hydrogen–potassium adenosine triphosphatase enzyme system (commonly called ‘the proton pump’). This is the final (and crucial) step in the process of gastric acid secretion. Proton pump inhibitors (PPIs), as their name indicates, are drugs that inhibit the proton pump, thereby reducing gastric acid secretion. PPIs are effective in treating dyspepsia, oesophageal reflux, in preventing or treating peptic ulcers and in helping eradicate Helicobacter pylori (Strand et al., 2017). First introduced in the late 1980s, PPIs are now among the most commonly prescribed drugs in the world (Savarino et al., 2017). PPI names end in ‘‐prazole’.

       Esomeprazole

       Lansoprazole

       Omeprazole

       Pantoprazole

       Rabeprazole

      Note an exception: a drug ending in ‘‐prazole’ that is not a proton pump inhibitor: aripiprazole (an atypical antipsychotic drug: see Chapter 5).

      Do not mistake PPIs ending in ‘‐prazole’ for antibiotics ending in ‘‐nidazole’ (i.e., metronidazole) or ‘‐oxazole’ (i.e., co‐trimoxazole) (see Chapter 9); or antifungals ending in ‘‐conazole’ (i.e., fluconazole: Chapter 9) or hormone antagonists ending in ‘‐rozole’ (i.e., letrozole: Chapter 10) [chemically, all of the above are azole derivatives, hence their ‘‐zole’ suffix].

References

      1 Ford, A.C., Talley, N.J., Spiegel, B.M. et al. (2008). Effect of fibre, antispasmodics and peppermint oil in the treatment of irritable bowel syndrome: systematic review and meta‐analysis. British Medical Journal, 337, a2313.

      2 Keshav, S. and Bailey, A. (2013). The gastrointestinal system at a glance. 2nd ed. Chichester: Wiley Blackwell.

      3 Puttmann, M. and Roett, M.A. (2011). H2 blockers are as effective as PPIs for long‐term relief of non‐ulcer dyspepsia. Evidence‐Based Practice, 14 (2), 14.

      4 Ruepert, L., Quartero, A.O., de Wit, N.J. et al. (2011). Bulking agents, antispasmodics and antidepressants for the treatment of irritable bowel syndrome. Cochrane Database of Systematic Reviews [online]. Available from: doi: 10.1002/14651858.CD003460.pub3.

      5 Savarino, V., Dulbecco, P., de Bortoli, N. et al. (2017). Appropriate use of proton pump inhibitors (PPIs): need for a reappraisal. European Journal of Internal Medicine, 37, 19–24 [online]. Available from: doi: 10.1016/j.ejim.2016.10.007.

      6 Strand, D.S., Kim, D. and Peura, D.A. (2017). 25 years of proton pump inhibitors: a comprehensive review. Gut and Liver, 11 (1), 27–37 [online]. Available from: doi: 10.5009/gnl.15502.