• Choose a category
• All
• Classic-Fiction

By Root 1837 0

nausea and increased sleepiness, in order to allay any fear. The patient should also be told that nausea and drowsiness are transitory and normally improve within 48 hours, but that constipation can be an ongoing problem and it is recommended that a laxative should be prescribed at the same time as the opioid is started. It is recommended that the most effective laxative for this group of patients is a combination of both a softening and a stimulating laxative (Davis et al. 2005).

Patients often have many concerns about commencing strong drugs such as morphine. Frequent fears centre around addiction and believing that its use signifies the terminal phase of the illness (McQuay 1999). Time should be taken to reassure patients and their families and provide verbal and written information.

Although morphine is still considered to be the opioid drug of choice for moderate to severe pain (Hanks et al. 2001), alternative opioids allow the practitioner to carefully assess the patient on an individual basis and select the most appropriate opioid to use.

Durogesic (fentanyl)

Fentanyl is a strong opioid, available in a patch, which is recommended in patients who have stable pain requirements. Transdermal patches are available in doses of 12, 25, 50, 75 or 100 μg/h. It is reported to have an improved side-effect profile in comparison to morphine (Ahmedzai and Brooks 1997), although some patients experience nausea and mild drowsiness (BMA/Royal Pharmaceutical Society of Great Britain 2008) and occasionally patients may develop a reaction to the adhesive in the patch (Ling 1997). Use of the patch has increased because it allows the patient freedom from taking tablets.

Changing of the patch is recommended every 3 days, and steady plasma levels are reported to be reached after 8–16 hours (Zech et al. 1994), although in some patients it may be necessary to change it more frequently. The patch should be applied to skin that is free from excess hair and any form of irritation and should not be applied to irradiated areas. It is advisable to change the location on the body to avoid an adverse skin reaction. Occasionally difficulties arise relating to the titration of the patch as each patch is equivalent to a range of morphine (Table 9.3).

Table 9.3 Recommended conversion doses from morphine to a fentanyl patch

Morphine dose in 24 hours (mg) Four-hourly morphine dose (mg) Fentanyl TTS (µg/h)

<50 2.5–5 12

50–134 5–20 25

135–224 25–35 50

225–314 40–50 75

315–404 55–65 100

405–494 70–80 125

495–584 85–95 150

585–674 100–115 175

675–764 115–125 200

765–854 130–140 225

855–944 145–155 250

945–1034 160–170 275

1035–1124 175–190 300

Fentanyl is also available in parenteral preparations. There are potential problems with fentanyl due to dose limitations. The ampoules are available in 50 μg/1 mL. If the dose required is too large a volume to use in the syringe driver, then alfentanil may be a useful alternative (Dickman et al. 2002).

Palladone (hydromorphone)

Palladone (hydromorphone) is mostly used when patients experience unacceptable drowsiness with morphine. It is similar to morphine in its pharmacokinetic profile and it is approximately 5.0–7.5 times more potent than morphine. It is available in immediate-release and sustained-release preparations and titration occurs in the same manner as morphine (Hays et al. 1994).

The side-effects are similar to those of morphine (Ellershaw 1998).

Methadone

Methadone is a synthetic opioid developed more than 40 years ago (Riley 2006). It is available in oral, rectal and parenteral preparations. There has been some reluctance amongst professionals to use methadone, which arose from the difficulties experienced in titrating the drug due to its long half-life (15 hours) that caused accumulation to occur, especially in the elderly (Gannon 1997). There are different methods of achieving effective titration (Gannon 1997); for example, one regimen is to calculate one-tenth of the total daily dose of morphine (maximum starting dose must not exceed 30 mg). Administer the methadone to the patient