Adverse effects clonidine

A number of non-hormonal therapies have been studied for symptomatic management of vasomotor symptoms, including antidepressants [e.g., selective serotonin reuptake inhibitors (SSRIs) and venlafaxine], herbal products (e.g., soy, black cohosh, and dong quai), and a group of miscellaneous agents (e.g., gabapentin, clonidine, and megestrol). The choice of therapy depends on the patient s concomitant disease states, such as depression and hypertension, and the risk for potential adverse effects. 

Geriatric Considerations - Summary Discontinuation of clonidine is likely to require a slow taper. If the patient is receiving a concomitant beta-blocker, the beta-blocker must be tapered and discontinued before discontinuing clonidine. Clonidine discontinuation in the presence of a beta-blocker can lead to severe hypertension and cardiovascular events due to unopposed alpha-receptor stimulation. CNS effects often preclude its use in older adults. A higher clonidine dose (0.4 mg/day) is generally needed to control peri- or postmenopausal vasomotor symptoms however, adverse effects often make it difficult to achieve effective doses. 

Clonidine (Catapres) Potential for orthostatic hypotension and CNS adverse effects. Low... 

Other medications, which will not be discussed in the following chapters, have psychotropic actions that are considered to be side effects or adverse effects. Thus, some antihistamines (Le. products used to counteract allergic reactions) induce fatigue and drowsiness, and the same applies to some myorelaxants. Older antihypertensives (Le. agents reducing blood pressure) such as alpha-methyldopa (Aldomet ) or clonidine (Catapres 1) can cause fatigue and depression. 

As indicated, buprenorphine can offer a quicker option than methadone, with a three-day course reported to be effective for withdrawal from heroin (Cheskin et al. 1994). The side-effects of clonidine which render it unsuitable for community treatment can be manageable in the inpatient setting, although the drug is being superseded by lofexidine where that is available. Controlled studies have found clonidine and lofexidine to be equally effective in alleviating withdrawal symptoms in inpatient detoxification from heroin (Lin et al. 1997) and from methadone (Khan et al. 1997), with lofexidine resulting in less hypotension and fewer adverse effects. Another double-blind controlled study found lofexidine to be broadly as effective as a ten-day methadone detoxification in inpatient opiate withdrawal (Bearn et al. 1996). 

Analogue of clonidine with fewer adverse effects, used in opiate detoxification... 

The most common adverse effects with clonidine are hypotension, dry mouth, drowsiness, and dermatoiogicai reactions. These are usually mild, but hypotensive effects may be significant in normotensive manic patients. Higher doses (e.g., 0.8 to 1.2 mg) have also been reported to induce a paradoxicai excitement in some patients (270). 

If these measures fail, clonidine, fluphenazine, clonazepam, or carbamazepine should be tried. The pharmacologic properties of these drugs are discussed elsewhere in this book. Clonidine reduces motor or vocal tics in about 50% of children so treated. It may act by reducing activity in noradrenergic neurons in the locus coeruleus. It is introduced at a dose of 2-3 mcg/kg/d, increasing after 2 weeks to 4 mcg/kg/d and then, if required, to 5 mcg/kg/d. It may cause an initial transient fall in blood pressure. The most common adverse effect is sedation other adverse effects include reduced or excessive salivation and diarrhea. Phenothiazines such as fluphenazine sometimes help the tics, as do dopamine... 

When tamoxifen is used in men (28), common adverse effects have included weight gain (25%), mood alterations (21%), hot flushes (21%), reduced libido (29%), and deep vein thrombosis (4%). The hot flushes respond well to oral clonidine 0.1 mg/day (29). 

Hypersalivation or sialorrhea has been reported with all neuroleptic drugs, and has been associated with risperidone as one of the most frequently mentioned adverse effects in patients with disturbing extrapyramidal symptoms during previous neuroleptic drug treatment (SEDA-25, 68). Hypersalivation is a troublesome adverse effect that can contribute to non-adherence to therapy, but it can be treated with clonidine. 

Serious adverse effects may occur if combined with clonidine (controversial)... 

Transdermal clonidine (clonidine TTS) has been used with some success for the treatment of mild hypertension. Systemic adverse effects are similar to those seen after oral administration, but are less frequent and milder. They include dry mouth, drowsiness, headache, sexual disturbance, cold extremities, obstipation, and fatigue (31-33). These adverse effects rarely necessitate withdrawal of clonidine TTS. 

Clonidine increases the analgesic effect of intrathecal neostigmine without enhancing its adverse effects (45). 

Effective postoperative pain relief can be obtained with a mixture of fentanyl and bupivacaine, which not only provides better analgesia than either drug alone, but also fewer adverse effects. There have been several studies of the efficacy of this mixture, using different doses and routes of administration, the addition of clonidine, and in comparison with morphine. 

Caudal bupivacaine has been successfully combined with clonidine, ketamine, diamorphine, and buprenor-phine, with increased duration of anesthesia and a low incidence of adverse effects (SEDA-20, 124) (SEDA-21,131). 

Opioids potentiate the analgesic effect of neuraxial local anesthetics, with minimal adverse effects (SEDA-18,141) (SEDA-20, 121) (SEDA-22, 135), as shown in several studies with clonidine, fentanyl, morphine, or pethidine as the systemic or neuraxial analgesic, and bupivacaine, lidocaine, and ropivacaine as the local anesthetic. The benefits have been shown in relief of long-term pain and postoperative pain, in adults and children (SEDA-18, 141) (SEDA-18,146). 

Clonidine has been reported to reduce both diastolic and systolic blood pressure by 10-15 mmHg during treatment for opioid withdrawal. Sedation and insomnia have also been noted. However, it is often difficult to distinguish which symptoms are due to the treatment and which are caused by opioid withdrawal. In a comparison of clonidine and methadone, seven of 14 patients in the clonidine group were withdrawn from the study because they had unacceptable adverse effects, compared with one of 11 in the methadone group. Two of those taking clonidine had severe immediate adverse effects that prevented them from continuing beyond 2 days (72). 

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